PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.4

Punjab State Board PSEB 7th Class Maths Book Solutions Chapter 4 Simple Equations Ex 4.4 Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Maths Chapter 4 Simple Equations Ex 4.4

Question 1.
If 7 is added to five times a number, the result is 57. Find the number.
Solution:
Let the required number = x
Five times the number = 5x
7 added to five times the number = 5x + 7
According to the problem
5x + 7 = 57
5x = 57 – 7
5x = 50
x = \(\frac {50}{5}\)
So, x = 10
Hence the required number is 10.

Question 2.
9 decreased from four times a number yields 43. Find the number.
Solution:
Let the required number = x
Four times the number = 4x
9 decreased from four times the number = 4x – 9
According to the problem
4x – 9 = 43
4x = 43 + 9
4x = 52
x = \(\frac {52}{4}\)
x = 13
Hence, the required number is 13.

Question 3.
If one-fifth of a number minus 4 gives 3, find the number.
Solution:
Let the required number = x
One fifth of the number = \(\frac {1}{5}\)x
One fifth of the number minus 4 = \(\frac {1}{5}\)x – 4
According to problem
\(\frac {1}{5}\)x – 4 = 3
\(\frac {1}{5}\)x = 3 + 4
\(\frac {1}{5}\)x = 7
x = 35
Hence the required number is 35.

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.4

Question 4.
In a class of 35 students, the number of girls is two-fifth the number of boys. Find the number of girls in the class.
Solution:
Let the number of boys = x
∴ number of girls = \(\frac {2}{5}\)x
Total number of students = 35
x + \(\frac {2}{5}\)x =35
\(\frac{5 x+2 x}{5}\) = 35
7x = 5 × 35
x = \(\frac{5 \times 35}{7}\)
x = 25
Therefore number of boys = 25
Number of girls = 35 – 25 = 10.

Question 5.
Sham’s father’s age is 5 years more than three times Sham’s age. Find Sham’s age, if his father is 44 years old.
Solution:
Let Sham’s age = x years
Then Sham’s father age = 3x + 5
But Sham’s fathers age = 44
According to question
3x + 5 = 44
3x = 44 – 5
3x = 39
Dividing both sides by 3
\(\frac{3 x}{3}=\frac{39}{3}\)
or x = 13
Hence Sham’s age is 13 years.

Question 6.
In an isosceles triangle the base angles are equal, the vertex angle is 40°. What are the base angles of the triangle ? (Remember, the sum of three angles of a triangle is 180°)
Solution:
Let each base angle of an isosceles triangle = x (in degrees)
Vertex angle = 40°
The sum of angles of a triangle = 180°
∴ x + x + 40° = 180°
2x = 180° – 40°
2x = 140°
Divide both sides by 2
\(\frac{2 x}{2}-\frac{140^{\circ}}{2}\)
Or x = 70°
Each equal angle is of 70°

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.4

Question 7.
Irfan says that he has 7 marbles more than five times the marbles Pannit has. Irfan has 37 marbles. How many marbles does Pannit have ?
Solution:
Let marbles Parmit has = x
Marbles Irfan has = 5x + 7
But Marbles Irfan has = 37
∴ 5x + 7 = 37
5x = 37 – 7
5x = 30
x = \(\frac {30}{5}\) = 6
Therefore Parmit has 6 marbles.

Question 8.
The length of a rectangle is 3 units more than its breadth and the perimeter is 22 units. Find the breadth and length of a rectangle.
Solution:
Let breadth of rectangle (l)
= x units
∵ length of rectangle (b) = (x + 3) units
∴ Perimeter of rectangle = 2(l + b)
= 2 (x + x + 3) units
= 2(2x + 3) units
According to the question
Perimeter = 22 units
2 (2x + 3) =22
\(\frac{2(2 x+3)}{2}=\frac{22}{2}\)
2x + 3 = 11
2x = 11 – 3
or 2x = 8
Dividing both sides by 2 we get
\(\frac{2 x}{2}=\frac{8}{2}\)
x = 4
∴ breadth = 4 units
Length = (4 + 3) units
= 7 units

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

This PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

→ In our daily life, the maximum things used by us are compounds of carbon.

→ All living species involve carbon.

→ A very small quantity of carbon present in nature is used by us.

→ Most of the carbon compounds are not good conductors of electricity.

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

→ The bonding of carbon compounds does not produce any ions.

→ The atomic number of carbon is 6. It has four electrons in its outermost shell.

→ It can gain four electrons forming C4- anion or it can lose four electrons forming C4+ cation.

→ Hydrogen requires one or more than one electron. The shared pair of electrons is said to constitute a single bond between two hydrogen atoms.

→ Chlorine forms a diatomic molecule.

→ Oxygen forms a double bond between two oxygen atoms.

→ In order to attain an octet, each nitrogen atom in a molecule of nitrogen contributes three electrons giving rise to three shared pairs of electrons.

→ Methane is a compound of carbon. It is the major component of bio-gas and compressed natural gas (CNG).

→ It is one of the simplest compounds of carbon.

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

→ Diamond and graphite are allotropes of carbon. They have the same chemical properties.

→ Fullerenes form another class of carbon allotropes which was first identified as C-60.

→ There are around 3 million carbon compounds in number.

→ The nature of a covalent bond enables carbon to form a very large number of compounds.

→ Carbon shows Catenation to the maximum extent.

→ The organic compounds having the presence of carbon-carbon single bonds only are termed saturated compounds.

→ The carbon-Carbon bond is very stable and strong.

→ Compounds of carbon are formed with oxygen, hydrogen, nitrogen, sulphur, chlorine, and some other elements.

→ Since carbon has a valency of four and is capable of bonding, it forms a large number of compounds.

→ The saturated compounds of carbon and hydrogen are methane, ethane, propane, butane, pentane, hexane.

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

→ The compounds with identical molecular formulas but different structures are called structural compounds.

→ In addition to straight and branched carbon chains, some compounds have carbon atoms arranged in the form of rings. For example, cyclohexane.

→ Saturated hydrocarbons are called ‘Alkanes’. Such unsaturated hydrocarbons which have one double bond are called ‘Alkenes’. Those having one triple bond are called Alkynes’.

→ All hydrocarbons burn in the presence of oxygen and release heat, light, and CO2.

→ Saturated hydrocarbons generally produce clean flame on burning while unsaturated carbon compounds produce a yellow flame with a lot of black smoke.

→ Incomplete combustion produces a sooty flame.

→ A flame is produced when gaseous substances are burnt.

→ Coal and petroleum are fossil fuels that have been formed from biomass that has been subjected to various biological and geological processes.

→ Alcohol can be converted into carboxylic acids by complete oxidation.

→ Substances that are capable of adding oxygen to other substances are known as oxidizing agents.

→ Catalysts are substances that cause a reaction to occur or accelerate the rate without reacting and getting affected.

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

→ Ethanol is a liquid at room temperature. Ethanol is commonly called alcohol.

→ Consumption of small quantities of ethanol tends to slow metabolic processes and depress the central nervous system.

→ Consumption of methanol even in very small quantity can cause death. It can also cause blindness by affecting the optic nerve.

→ Methanol is mixed with ethanol to prevent its misuse. Dyes are added to colour the alcohol blue. This is called denatured alcohol.

→ Sugarcane juice can be used to prepare molasses which is fermented to give ethanol.

→ Ethnic acid is commonly called acetic acid. 3.4% solution of acetic acid in water is called vinegar.

→ Carbon: Carbon is an element that is of immense significance in its elemental and combined form. Placed in 14th group of periodic table with atomic number 6, mass number 12 and electronic configuration 4 it has electronic valency 2, 4 and is symbolised as \({ }_{6}^{12} \mathrm{C}\).

→ Carbon compounds: The compounds in which carbon is present are called carbon compounds. These are generally covalent. Ionic compounds of carbonates are not included in this.

→ Covalent bonds: The bond formed by sharing of electrons is known as a covalent bond.

→ Allotropy: The property of an element by virtue of which it can exist in two or more physical forms of the same chemical element, with the same chemical properties.

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

→ Hydrocarbons: The covalent compounds of hydrogen and carbon are called hydrocarbons.

→ Saturated hydrocarbons: The hydrocarbons with the same chemical formula CnH2n+2 are called alkane. These have a covalent bond between the members of the same category.

→ Isomerism: The compounds with the same molecular formula but different structural formulas are called isomers and the phenomenon is known as isomerism.

→ Unsaturated Hydrocarbons: The compounds of carbon having double or triple bonds between the carbon atoms are known as unsaturated hydrocarbons.

→ Alkene: Generally a hydrocarbon with the chemical formula CnH2n is called alkene.

→ Alkyne: The carbon compound containing a triple bond between carbon atoms is called alkyne.

→ Catenation: The carbon atoms form bonds with other carbon atoms to form long-chained compounds. This property is known as catenation.

→ Allotropy: The phenomenon of the existence of two or more physical forms of the same chemical element, with the same chemical properties, is called allotropy.

→ Fullerenes: There are the allotropes of carbon having a football or bucky ball-like structure.

→ Addition reactions: These are the reactions in which some molecules get added to unsaturated Hydrocarbon like alkene/alkyne.

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

→ Substitution reactions: These are the reactions in which an atom or group of atoms from an organic compound is replaced by another atom or group.

→ Esterification: The reaction of a carboxylic acid with an alcohol to form an ester is called esterification.

→ Functional group: An atom or group of atoms that determines the chemical properties of an organic compound is called a functional group.

→ Fermentation: The process of conversion of complex organic compounds into simple organic compounds with the help of enzymes is known as fermentation.

→ Alcohol: The compound obtained by the replacement of a hydrogen atom of alkane by hydroxyl (-OH) functional group is called alcohol: Its general formula is CnH2n+1 OH.

→ Carboxylic acid: Carboxylic acids are those organic compounds that have (-COOH) as a functional group.

→ Homologous series: A series of organic compounds having the same functional group formula and possessing similar chemical properties are termed homologous series.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

This PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Iron, Copper, Aluminium, Magnesium, Sodium, Lead, Zinc, etc. Metals are easily available.

→ Metals have shining surfaces, called metallic luster.

→ Sodium metal can be cut by a knife.

→ Metals are usually hard and can be beaten into thin sheets and drawn into wires.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Gold is most ductile that is why from one gram of gold, a 2km long wire can be drawn.

→ Metals are good conductors of heat.

→ Malleability and ductility are two important properties of metals.

→ Lead and mercury are bad conductors whereas silver and copper are very good conductors.

→ Metals have sonorous properties.

→ Carbon, Sulphur, Iodine, Oxygen, Hydrogen etc. are non-metals.

→ Bromine is a non-metal which exists in liquid form.

→ Mercury exists in liquid form at room temperature.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Gallium and Cesium have a very low melting point, which melts even when placed on our palms.

→ Iodine is non-metal but is lustrous.

→ Lithium, Sodium, Potassium are alkali metals and are very soft, they can be cut with a knife.

→ Most of the non-metals produce acidic oxides when dissolved in water.

→ Magnesium burns in the air with dazzling white flame.

→ On heating copper, it changes to black coloured copper oxide.

→ Those metal oxides that react with acid as well as with bases and produce salt and water in both cases are called amphoteric oxides.

→ Gold and silver do not react with oxygen even on heating.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Aqua regia is a fresh mixture of concentrated HCl and Concentrated HNO3 in the ratio 3 : 1.

→ Aqua regia can dissolve in Gold and platinum.

→ Reactivity series is a list of metals in which metals are arranged in decreasing activity.

→ Noble gases have completely filled valence shells and thus are less reactive.

→ Helium, Neon, Argon are Noble gases.

→ Compounds formed by the transfer of electrons from metals to non-metals are called ionic or electrovalent compounds.

→ Ionic compounds are solid and hard. They have high melting and boiling point. They can conduct electricity.

→ Earth’s crust is the main source of metals.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ The elements or compounds which occur naturally in the earth’s crust are called minerals.

→ Some of the minerals from which extraction of metals is easy and profitable are called ores.

→ Gold, silver, platinum, and copper are at the bottom of the reactivity series and are least reactive, and are found in a free state.

→ Zinc, Iron, lead are moderately reactive and are found in the form of oxide, sulphide, or carbonate in the Earth’s crust.

→ Sodium, Potassium, calcium, Magnesium, Aluminium, etc. are at the top of the reactivity series and are so reactive that they are never found in a free state in nature.

→ Ores are contaminated with impurities like soil, sand, etc. known as gangue.

→ If sulphide ores are heated in excess air, they convert to oxides. This is called roasting.

→ Carbonate ores are converted into oxides by heating them strongly in a limited supply of air. This is known as calcination.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ The reaction of iron oxide with aluminium is called the thermit reaction.

→ Electrolytic refining is used to purify metals.

→ Silver articles become black after some time when exposed to air due to the formation of a coating of silver sulphide.

→ Copper gains a green coating of basic copper carbonate due to corrosion when left in air for a long time CuCO3.Cu(OH)2.

→ Iron acquires a brown coating called rust.

→ Corrosion is prevented by greasing, painting, galvanising, chrome plating, anodizing, etc.

→ The homogeneous mixture of two or more two metals is called an alloy.

→ Pure Gold, which is 24-carat gold, which is very soft.

→ For making ornaments silver or copper is mixed with gold.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Generally, 22-carat gold is used for making ornaments. If alloy contains one of its constituents as mercury (Hg) it is called amalgam.

→ Alloy Bronze is a bad conductor of electricity.

→ Ductility: It is a property of metals by virtue of which long wires can be drawn. Electric wire is an example of ductility.

→ Malleability: It is a property of metals by virtue of which metals can be beaten into thin sheets.

→ Conductivity: Metals allow the passage of heat and electricity through them, this is called conductivity.

→ Mineral: Substances from which metals can be extracted are called minerals. Metals can be extracted from minerals by different methods.

→ Metallurgy: To extract metals from their ores and purify them for use is called metallurgy.

→ Ore: Those minerals from which metal extraction is easy and profitable are called ores.

→ Gangue: Ores mined from the earth are contaminated with impurities such as soil, sand, etc. are called gangue.

→ Roasting: The process of converting enriched ore in the excess of air is called roasting.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Reduction: It is a process of obtaining metals from compounds.

→ Purification: It is a process of obtaining pure metal from impure metal.

→ Alloy: Mixture of a metal with other metal or non-metal in the called alloy.

→ Allotropy: A property by virtue of which non-metals exist in different forms is called allotropy.

→ Vulcanization: Mixing sulphur with natural rubber is called vulcanization and such rubber is called vulcanized rubber.

→ Slag: It is a substance that is obtained when gangue and smelter are together.

→ Smelter: It is a substance which is used to separate gangue in the form of liquid from an impure metal.

→ Calcination: It is a process of heating ore in the limited supply of air. Ore becomes porous in this process.

→ Smelting: It is a process to extract an element from its ore using heat and a reduction agent.

→ Metals: Metals are those elements which lose electrons to form positive ions.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Non-Metals: Non-Metals are those elements which gain electrons to form negative ions.

→ Amalgam: When one of the constituents of an alloy is mercury it is called an alloy.

→ Corrosion: The effect of air, water, or any other substance on the surface of the metal is called corrosion.

→ Strategic metals: These are the metals that are important for the economy and safety of the country are strategic metals.

→ Electropositive elements: Those elements which lose electrons to form positive ions are known as electropositive elements: Metals belong to this category.

→ Electronegative elements: Those elements which gain electrons to form negative ions are known as electronegative elements. Non-metals belong to this category.

→ Reactivity series of metals: Arrangement of metals in a column in decreasing reactivity of metals is called reactivity series of metals.

→ Displacement reactions: The replacement of less reactive metal by more reactive metal from its salt in a reaction is called displacement reaction.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Catalyst: These are substances that do not take part in a reaction but can increase or decrease the rate of reaction are called catalysts.

→ Promotor: Substances that increase the performance of catalysts are called promotors.

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.3

Punjab State Board PSEB 7th Class Maths Book Solutions Chapter 4 Simple Equations Ex 4.3 Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Maths Chapter 4 Simple Equations Ex 4.3

1. Solve each of the following equation.

Question (i).
6x + 10 = – 2
Answer:
Given equation is 6x + 10 = – 2
Transposing + 10 from L.H.S to R.H.S
we get
6x = -2 – 10
or 6x = -12
Dividing both sides by 6, we get
\(\frac{6 x}{6}=\frac{-12}{6}\)
or x = – 2, which is the required solution.

To check Put x = – 2 in the LHS of the equation 6x + 10 = – 2
L.H.S. = 6x + 10
= 6 × -2 + 10
= -12 + 10
= – 2 = R.H.S.
∴ L.H.S. = R.H.S.

Question (ii).
2y – 3 = 2
Answer:
Given equation is 2y – 3 = 2
Transposing – 3 from L.H.S. to R.H.S,
we get
2y = 2 + 3
or 2y = 5
Dividing both sides by 2, we get:
\(\frac{2 y}{2}=\frac{5}{2}\)
or y = \(\frac {5}{2}\), which is the required solution

To check. Put y = \(\frac {5}{2}\) in the L.H.S of the equation 2y – 3 = 2
L.H.S = 2y – 3 = 2 × \(\frac {5}{2}\) – 3
= 5 – 3 = 2 = R.H.S.
∴ L.H.S. = R.H.S.

Question (iii).
\(\frac{a}{5}\) + 3 = 2
Answer:
Given equation is \(\frac{a}{5}\) + 3 = 2
Transposing + 3 from L.H.S to R.H.S., we get
\(\frac{a}{5}\) = 2 – 3
or \(\frac{a}{5}\) = -1
Multiplying both sides, by 5, we get
5 × \(\frac{a}{5}\) = 5 × – 1
or a = – 5, which is the required solution.

To Check: Put a = – 5 in the L.H.S of the equation
\(\frac{a}{5}\) + 3 = 2,
L.H.S. = \(\frac{a}{5}\) + 3
= \(\frac {-5}{5}\) + 3
= – 1 + 3
= 2 = R.H.S.
∴ L.H.S. = R.H.S.

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.3

Question (iv).
\(\frac{3 x}{2}=\frac{2}{3}\)
Answer:
Given equation is \(\frac{3 x}{2}=\frac{2}{3}\)
Multiplying both sides by 2, we get
2 × \(\frac{3 x}{2}\) = 2 × \(\frac {2}{3}\)
or 3x = \(\frac {4}{3}\)
Dividing both sides by 3 we get
\(\frac{3 x}{3}=\frac{4}{3} \times \frac{1}{3}\)
or x = \(\frac {4}{9}\), which is the required solution.

To Check. Put x = \(\frac {4}{9}\) in the L.H.S. of equation \(\frac{3 x}{2}=\frac{2}{3}\)
L.H.S. = \(\frac{3 x}{2}=\frac{3}{2} \times \frac{4}{9}\) = \(\frac {2}{3}\) = R.H.S.
∴L.H.S. = R.H.S.

Question (v).
\(\frac {5}{2}\)x = -5
Answer:
Given equation is \(\frac {5}{2}\) x = – 5
Multiplying both sides by 2, we get
2 × \(\frac {5}{2}\) x = 2 × – 5
or 5x = – 10
Dividing both sides by 5, we get
\(\frac{5 x}{5}=\frac{-10}{5}\)
or x = – 2, which is the required solution.

To Check. Put x = – 2 in L.H.S. of the equation \(\frac {5}{2}\)x = – 5
L.H.S. = \(\frac {5}{2}\)x = \(\frac {5}{2}\) × -2
= – 5 = R.H.S.
∴ L.H.S. = R.H.S.

Question (vi).
2x + \(\frac {5}{2}\) = \(\frac {37}{2}\)
Answer:
Given equation is 2x + \(\frac {5}{2}\) = \(\frac {37}{2}\)
Subtract \(\frac {5}{2}\) from both sides, we get
2x + \(\frac {5}{2}\) – \(\frac {5}{2}\)
= \(\frac {37}{2}\) – \(\frac {5}{2}\)
or 2x = \(\frac{37-5}{2}\)
or 2x = \(\frac {32}{2}\)
or 2x = 16
Dividing both sides by 2, we get
\(\frac{2 x}{2}=\frac{16}{2}\)
or x = 8, which is the required solution.

To Check. Put x = 8 in the L.H.S. of the equation 2x + \(\frac {5}{2}\) = \(\frac {37}{2}\)
L.H.S. = 2x + \(\frac {5}{2}\)
= 2 × 8 + \(\frac {5}{2}\)
= 16 + \(\frac {5}{2}\)
= \(\frac{32+5}{2}\)
= \(\frac {37}{2}\) = R.H.S.
∴ L.H.S. = R.H.S.

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.3

2. Solve the following equation

Question (i).
5 (x + 1) = 25
Answer:
Given equation is 5 (x + 1) = 25
Dividing both sides by 5 we get
\(\frac{5(x+1)}{5}=\frac{25}{5}\)
or x + 1 = 5
Transposing 1 from L.H.S. to R.H.S. we get
x = 5 – 1
or x = 4, which is the required solution.

To Check. Put x = 4 in the L.H.S. of the equation 5 (x + 1) = 25
L.H.S. = 5 (x + 1)
= 5 (4 + 1)
= 5 (5)
= 25 = R.H.S.
∴ L.H.S. = R.H.S.

Question (ii).
2 (3x – 1) = 10
Answer:
Given equation is 2 (3x – 1) = 10
Dividing both sides by 2, we get
\(\frac{2(3 x-1)}{2}=\frac{10}{2}\)
or 3x – 1 = 5
Transposing – 1 from L.H.S. to R.H.S we get
3x = 5 + 1
3x = 6
Dividing both sides by 3, we get \(\frac{3 x}{3}=\frac{6}{3}\)
or x = 2, which is the required solution.

To Check. Put x = 2, in the L.H.S. of the equation 2 (3x – 1) = 10
L.H.S. = 2 (3x – 1) = 10
L.H.S = 2 (3x – 1) = 2 (3 × 2 – 1)
= 2 (6 – 1)
= 2 × 5
= 10 = R.H.S.
∴L.H.S. = R.H.S.

Question (iii).
4 (2 – x) = 8
Answer:
Given equation is 4 (2 – x) = 8
Dividing both sides by 4, we get
\(\frac{4(2-x)}{4}=\frac{8}{4}\)
or 2 – x= 2
Transposing 2 from L.H.S. to R.H.S. we get
-x = 2 – 2
or – x = 0
Multiplying both sides by – 1, we get
-x × – 1 = x – 1
or x = 0, which is the required solution.

To Check. Put x = 0 in the L.H.S. of the equation 4 (2 – x) = 8
L.H.S. = 4 (2 – x) = 4 (2 – 0)
= 4 × 2
= 8 = R.H.S.
∴ L.H.S. = R.H.S.

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.3

Question (iv).
– 4 (2 + x) = 8.
Answer:
Given equation is – 4 (2 + x) = 8
Dividing both sides by – 4, we get
\(\frac{-4(2+x)}{-4}=\frac{8}{-4}\)
Transposing 2 from L.H.S. to R.H.S. we get :
x = – 2 – 2
or x = – 4, which is the required solution

To Check. Put x = – 4 in the L.H.S. of equation – 4 (2 + x) = 8
L.H.S. = – 4 (2 + x) = – 4 [2 + (- 4)]
= – 4 (2 – 4)
= – 4 (- 2)
= 8 = R.H.S.
∴ L.H.S. = R.H.S.

3. Solve the following equations :

Question (i).
4 = 5 (x – 2)
Answer:
Given equation is 4 = 5 (x – 2)
or 4 = 5x – 10
Transposing 5x to L.H.S. and 4 to R.H.S.,
we get
– 5x = – 4 – 10
or – 5x = – 14
Dividing both sides by – 5, we get
\(\frac{-5 x}{-5}=\frac{-14}{-5}\)
or, x = \(\frac {14}{5}\), which is the required solution.

To Check. Put x = \(\frac {14}{5}\) in the R.H.S. of the equation 4 = 5 (x – 2)
R.H.S. = 5 (x – 2) = 5\(\left(\frac{14}{5}-2\right)\)
= 5\(\left(\frac{14-10}{5}\right)\)
= 5 \(\left(\frac{4}{5}\right)\)
= 4 = L.H.S.
∴ L.H.S. = R.H.S.

Question (ii).
– 4 = 5 (x – 2)
Answer:
Given equation is – 4 = 5 (x – 2)
or – 4 = 5x – 10
Transposing -4 to R.H.S and 5x to L.H.S
we get
-5x = 4 – 10 or -5x = -6
Dividing both sides by – 5 we get
\(\frac{-5 x}{-5}=\frac{-6}{-5}\)
or x = \(\frac {6}{5}\), which is the required solution.

To Check. Put x = \(\frac {6}{5}\) in the R.H.S. of the equation – 4 = 5 (x – 2)
L.H.S. = 5 (x – 2)
= 5\(\left(\frac{6}{5}-2\right)\)
= 5\(\left(\frac{6-10}{5}\right)\)
= 5\(\left(\frac{-4}{5}\right)\)
= -4 = L.H.S.
L.H.S. = R.H.S.

Question (iii).
4 + 5 (p – 1) = 34
Answer:
Given equation is 4 + 5(p – 1) = 34
Transposing 4 to R.H.S. we get
5(p – 1) = 34 – 4
5(p – 1) = 30
Dividing both sides, by 5, we get
\(\frac{5(p-1)}{5}=\frac{30}{5}\)
p – 1=6
Transposing -1 to R.H.S. we get
p = 6 + 1
p = 7 which is the required solution.

To Check : Put p = 7 in L.H.S. of the equation 4 + 5 (p – 1) = 34
L.H.S. = 4 + 5 (p – 1)
= 4 + 5 (7 – 1)
= 4 + 5 (6)
= 4 + 30
= 34 = R.H.S.
∴ L.H.S. = R.H.S.

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.3

Question (iv).
6y – 1 = 2y + 1.
Answer:
Given equation is 6y – 1 = 2y + 1
Transposing – 1 to R.H.S. and 2y to L.H.S,
we get
6y – 2y = 1 + 1
or 4y = 2 or y = \(\frac {2}{4}\)
or y = \(\frac {1}{2}\), which is the required solution.

To Check Put y = \(\frac {1}{2}\) in both L.H.S. and R.H.S. of the equation
6y – 1 = 2y + 1
L.H.S. = 6y – 1 = 6 × \(\frac {1}{2}\) – 1 = 3 – 1 = 2
R.H.S. = 2y + 1 = 2 × \(\frac {1}{2}\) + 1 = 1 + 1 = 2.
∴ L.H.S. = R.H.S.

4.

Question (i).
Construct 3 equations starting with x = 2
Answer:
First Equation.
(i) Start with x = 2
Multiplying both sides by 10
10x = 20
Adding 2 to both sides
10x + 2 = 20 + 2
or 10x + 2 = 22
This has resulted in an equation.

Second Equation. Start with x = 2
Divide both sides by 5
∴ \(\frac{x}{5}=\frac{2}{5}\)
This has resulted in an equation.

Third Equation. Start with x = 2
Multiply both sides by 5, we get
5x = 5 × 2
or 5x = 10
Subtracting 3 from both sides, we get
5x – 4 = 10 – 3
or 5x – 3 = 7
This has resulted in an equation.

Question (ii).
Construct 3 equation starting with x = – 2
Answer:
First Equation. Start with x = – 2
Multiplying both sides with 3, we get
3x = – 6
This has resulted in an equation

Second Equation. Start with x = – 2
Multiplying both sides with 3, we get 3x = -6
Adding 7 to both sides, we get 3x + 7
= -6 + 7 or 3x + 7 = 1
This has resulted in an equation.

Third Equation. Start with x = – 2
Multiplying both side with 2 we get 3x = – 6
Adding 10 to both sides we get
3x+ 10 = -6 + 10
or 3x + 10 = 4
This has resulted in an equation.

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.3

Multiple Choice Questions :

5. If 7x + 4 = 39, then x is equal to :
(a) 6
(b) -4
(c) 5
(d) 8
Answer:
(c) 5

6. If 8m – 8 = 56 then m is equal to :
(a) -4
(b) -2
(c) -14
(d) 8
Answer:
(d) 8

7. Which of the following number satisfies the equation – 6 + x = -18 ?
(a) 10
(b) – 13
(c) – 12
(d) – 16.
Answer:
(a) 10

8. If \(\frac{x}{2}\) = 14, then the value of 2x + 6 is equal to :
(a) 62
(b) -64
(c) 16
(d) -62.
Answer:
(a) 62

PSEB 7th Class Maths Solutions Chapter 4 Simple Equations Ex 4.3

9. If 3 subtracted from twice a number is 5, then the number is :
(a) -4
(b) -2
(c) 2
(d) 4
Answer:
(d) 4

10. If 5 added to thrice an integer is – 7, then the integer is :
(a) – 6
(b) – 5
(c) -4
(d) 4
Answer:
(c) -4

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

This PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

→ The sour taste of foods is due to acids and the bitter taste is due to bases present in them. Acids turn blue litmus into red and bases turn the red litmus into the blue.

→ Acids and bases neutralize each other’s effects.

→ Acids and bases can be tested using litmus, turmeric, methyl orange, and phenolphthalein indicators.

→ On passing carbon dioxide gas through lime water, lime water turns milky.

→ On passing, excess carbon dioxide gas through lime water, its milky colour disappears due to the formation of soluble calcium bicarbonate.

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

→ Bases turn phenolphthalein pink in colour.

→ Acids and bases react to produce salt and water.

→ The flow of current in the solution is due to ions present in the solution.

→ In acids H+ ions are present. Acids produce hydrogen ion H+(aq) in a solution due to which solutions become acidic.

→ Bases produce hydroxide (OH) ions in water.

→ Alkali is a base that dissolves in water.

→ Bases are soapy to touch, bitter, and corrosive.

→ All acids produce H+(aq) and bases produce OH(aq) in an aqueous solution.

→ The process of the dissolving of acids or bases in water is highly exothermic, therefore to dilute them these should be added and mixed slowly in water. Never add water to concentrated acid.

→ A universal indicator is a mixture of several indicators.

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

→ Universal indicators show different colors for different concentrations of hydrogen ions in the solution.

→ A scale known as the pH scale has been developed for measuring the concentration of hydrogen ions present in the solution.

→ The ‘p’ in pH stands for ‘potenz’ this is a German word which means power.

→ On the pH scale, we can measure pH generally from 0 (very acidic) to 14 (very basic).

→ Higher is the concentration of hydronium ion, less is the value of pH. A neutral solution has a pH value of 7.

→ If the value of pH is less than 7 then the solution is acidic and if pH lies between 7 to 14 then the solution is basic.

→ Those acids which produce a large number of H+ ions are called strong acids and those acids which produce less H+ ions are weak acids.

→ Our body works in the range of 7.0 to 7.8.

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

→ When the pH value of rainwater is less than 5.6 it is called acid rain.

→ To get rid of acidity in the body, and antiacid like magnesium hydroxide which is a weak base is used.

→ If the pH value is less than 5.5 in the mouth, decay of teeth starts.

→ Nettle is a herbaceous plant that causes painful stings due to methanoic acid present in stinging hair. A traditional remedy is rubbing the area with the leaf of the dock plant.

→ Common salt (NaCl) is produced by the reaction between hydrochloric acid and sodium hydroxide.

→ Bleaching powder is produced by the action of chlorine on dry slaked lime.

→ Bleaching powder is used in the paper and textile industry for bleaching. It acts as an oxidant and as a disinfectant.

→ Baking soda (NaHCO3) is produced from sodium chloride.

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

→ Sodium hydrogen carbonate is a mild non-corrosive base. It is used in the production of Baking powder and used in the preparation of cakes. It is also used in fire extinguishers.

→ Washing soda (NagCO3.10H2O) is prepared from sodium chloride. It is used in the glass, soap, paper industries. It is used to remove the permanent hardness of the water.

→ The chemical formula for hydrated copper sulfate is CuSO4.5H2O and of gypsum is CaSO4.2H2O.

→ Plaster of Paris is obtained from calcium sulphate hemihydrate (CaSO4. \(\frac{1}{2}\) H2O) by heating it at 373K.

→ Plaster of Paris is used for making toys and material for decoration.

→ Indicators: These are the substances that give different colors in acidic and basic solutions e.g. litmus, turmeric, phenolphthalein, methyl orange, etc.

→ Olfactory Indicators: There are some substances whose odour changes in acidic or basic media, which are known as olfactory indicators.

→ Acid: Those compounds which have one or more hydrogen atoms and which give hydrogen (H+) or hydronium (H3O+) ions (H3O+) ion in an aqueous solution are called acids. These are sour in taste.

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

→ Ionization: It is a process in which a substance produces ions in water, ionization.

→ Basicity of an acid: Basicity of an acid is the number of hydronium ions [H+] produced when one molecule of acid gets completely ionized in an aqueous solution.

→ Base: Bases are those compounds which are metal oxides or metal hydroxide or aqueous ammonia and these react with hydronium ion (H3O+) of acids to produce salt and water.

→ Neutralization: Due to the reaction between acids and bases, salt and water are produced. This is called a neutralization reaction.

→ Alkali: Those basic hydroxides which on dissolving in water form hydroxyl (OH) ions, are called alkali.

→ Universal indicator: It is a mixture of various organic substances which show different colours with solutions having different pH values.

→ Dissociation: When a molecule or ionic compound dissociates into two or more atoms or ions, this is called dissociation.

→ Chemical dissociation: A reaction in which a molecule of a compound breaks into atoms or ions is called chemical dissociation.

→ The water of Crystallisation: Water, which is present in crystals of a substance is called water of crystallization. e.g., FeSO4.7H2O, Al2O3.2H2O, CuSO4.5H2O, Na2CO3.10H2O.

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

→ Efflorescence: The process of release of crystalline water from hydrated salts into the air is called efflorescence.

→ Deliquescence: This is a process in which a substance absorbs moisture from the atmosphere and dissolves in the absorbed water to form a solution.

→ Dilution: On mixing acid or base in water, the concentration of ions (H3O+/OH) per unit volume becomes less. This is called dilution.

→ Chlor-alkali process: The electrolysis of sodium chloride solution is called chlor-alkali process.

PSEB 10th Class Science Solutions Chapter 16 Management of Natural Resources

Punjab State Board PSEB 10th Class Science Book Solutions Chapter 16 Management of Natural Resources Textbook Exercise Questions and Answers.

PSEB Solutions for Class 10 Science Chapter 16 Management of Natural Resources

PSEB 10th Class Science Guide Management of Natural Resources Textbook Questions and Answers

Question 1.
What changes would you suggest in your home in order to be environment friendly?
Answer:
We should use the formula of three R’s to save the environment i.e. Reduce, Recycle and Reuse.

  • Reduce: Use less, save water and electricity by stopping the wastage. Do not waste food.
  • Recycle: Segregate the wastes so that material which can be recycled should be dumped in place for recycling.
  • Reuse: Reuse certain articles e.g. reverse the used envelope and reuse it.

Question 2.
Can you suggest some changes in your school which could make it environment friendly?
Answer:
We should use the formula of three R’s to save the environment i.e. Reduce, Recycle and Reuse.

  • Reduce: Use less, save water and electricity by stopping the wastage. Do not waste food.
  • Recycle: Segregate the wastes so that material which can be recycled should be dumped in place for recycling.
  • Reuse: Reuse certain articles e.g. reverse the used envelope and reuse it.

Question 3.
We have read in this chapter that there are four main stakeholders when it comes to forests and wild-life. Which among these should have the authority to decide the management of forest produce? Why do you think so?
Answer:
By active and willing participation of local people, the sal forests of Arabari under went a remarkable recovery as 25 per cent of final harvest was provided to people. They were allowed fuel wood and fodder collection at very nominal rates. This project helped in saving the forests. Hence to have sustainable development there should be equal participation of local community.

PSEB 10th Class Science Solutions Chapter 16 Management of Natural Resources

Question 4.
How can you as an individual contribute or make a difference to the management of
(a) forest and wild-life
Answer:

  • Selective use and reuse of resources.
  • Discourage the killing of wild animals.
  • Educate the people about the resources provided by forests.

(b) water resources and
Answer:
Water harvesting at one’s home level so as to restore water at subsoil level.

(c) Coal and Petroleum?
Answer:
Alternative sources of energy such as use of solar energy instead of coal and petroleum.

Question 5.
What can you, as an individual, do to reduce your consumption of the various natural resources?
Answer:
(a) forest and wild-life

  • Selective use and reuse of resources.
  • Discourage the killing of wild animals.
  • Educate the people about the resources provided by forests.

(b) water resources
Water harvesting at one’s home level so as to restore water at subsoil level.

(c) Coal and Petroleum
Alternative sources of energy such as use of solar energy instead of coal and petroleum.

Question 6.
List five things you have done over the last one week to :
(i) conserve our natural resources
Answer:
Conserve our natural resources

  • Saved electricity by switching off electricity of unnecessary light and fans.
  • Used disposable paper cups and plates during my journey in the train.
  • Reused the envelopes by turning inside out.
  • Planted five plants in my school.
  • Educated the people in my locality regarding conservation of natural resources for sustainable development.

(ii) increase the pressure on our natural resources.
Answer:
Increase the pressure on natural resources

  • Wasted food.
  • Used scooter to consume petrol.
  • Added to air pollution and sound pollution.
  • Used plastic bags.
  • Used D.D.T. in my home.

Question 7.
On the basis of the issues raised in this chapter, what changes would you incorporate in your life-style in a move towards a sustainable use of our resources?
Answer:
forest and wild-life

  • Selective use and reuse of resources.
  • Discourage the killing of wild animals.
  • Educate the people about the resources provided by forests.

(b) water resources
Water harvesting at one’s home level so as to restore water at subsoil level.

(c) Coal and Petroleum
Alternative sources of energy such as use of solar energy instead of coal and petroleum.

Conserve our natural resources

  • Saved electricity by switching off electricity of unnecessary light and fans.
  • Used disposable paper cups and plates during my journey in the train.
  • Reused the envelopes by turning inside out.
  • Planted five plants in my school.
  • Educated the people in my locality regarding conservation of natural resources for sustainable development.

Increase the pressure on natural resources

  • Wasted food.
  • Used scooter to consume petrol.
  • Added to air pollution and sound pollution.
  • Used plastic bags.
  • Used D.D.T. in my home.

Science Guide for Class 10 PSEB Management of Natural Resources InText Questions and Answers

Question 1.
What changes can you make in your habits to become more environment friendly?
Answer:
Changes in habits to become environment friendly

  • Check your careless habit of wasting. Save water by repairing leaking taps.
  • Switch off unnecessary lights and fans.
  • Do not waste food.
  • Say ‘No’ to plastic bags, disposable plastic cups and other forms of plastic crockery.
  • Reuse the things again and again. Instead of throwing away envelopes, you can reverse it and use it again.

PSEB 10th Class Science Solutions Chapter 16 Management of Natural Resources

Question 2.
What would be the advantages of exploring resources with short term aims?
Answer:
The advantages of exploiting resources with short term aims are as follows :

  • We will be able to fulfil the requirement of mass population.
  • We will be able to get industrial growth and hence economic development is linked to environmental conservation.

Question 3.
How would these advantages differ from the advantages of using a long term perspective in managing our resources?
Answer:
The demand for all resources is increasing due to increasing human population. The resources are limited.

  • It should ensure selective careful use so as to maintain.
  • There should be equal distribution of resources to all i.e. rich and poor.
  • There should be safe disposal of wastes.

Question 4.
Why do you think there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?
Answer:
Management of resources should ensure equitable distribution of resources to all and not to just a handful of rich and powerful people, benefit from the development of these resources.

Question 5.
Why should we conserve forest and wildlife?
Answer:
Forests and wild life are resources of great value.

  • Forests help in protection of land.
  • Forests help in retaining sub-soil water.
  • Forests check floods.
  • Forest and wild life maintain ecosystem.
  • Wildlife is helpful in exploiting various scientific researches.
  • They should be maintained for our economic and social growth and to meet our and of future generation’s material aspiration.

Question 6.
Suggest some approaches towards conservation of forests.
Answer:
Conservation of forests

  • Participation of local people indeed lead to efficient management of forest as exemplified by strategy developed in Arabari Forest range of Midnapur district.
  • Replantation of trees.
  • Selective use of forests.
  • Scientific research, monitoring and education plays vital role in conservation.
  • Overgrazing should be checked.
  • Protection of wildlife and banning the hunting of wild animals.
  • Use of modern technique of forestry.
  • Make suitable outlet channels to carry out flood water.

Question 7.
Find out about the traditional system of water harvesting/management of your region.
Answer:
Traditional Methods in water harvesting/management

  • Diversion of water flowing in streams into man-made channels to cater to the demand of villagers.
  • Collection of water in ponds.
  • Construction of dams.

Question 8.
Compare the above system with the probable system in hilly mountainous areas or plains or plateau regions.
Answer:
Water harvesting systems are highly local specific and benefits are also localized. The present-day systems include mega projects such as dams.

Question 9.
Find out the source of water in your region/locality. Is water from this source available to all people living in that area?
Answer:
Sources of water are different in different areas. However, these sources are available to all people.

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Punjab State Board PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources Important Questions and Answers.

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Long Answer Type Questions

Question 1.
Explain the three R’s to serve the environment.
Answer:
The three R’s to save the environment : Reduce, Recycle and Reuse. What do they refer to?

  • Reduce: This means that use less. Save electricity by switching off unnecessary lights and fans. Save water by repairing leaky taps. Do not waste food.
  • Recycle: This means that collection of plastic, paper, glass and metal items and recycle this material to make required things instead of synthesising or extracting fresh plastic, paper, glass or metal. In order of recycle, first need to segregate waste so that the material that can be recycled is not dumped along with other waste.
  • Reuse: This is actually even better than recycling because the process of recycling uses some energy. In the ‘reuse’ strategy, simply use things again and again. Instead of throwing away used envelopes, you can reverse it and use it again. The plastic bottles in which you buy various food-items like jam or pickle can be used for storing things in the kitchen.

Question 2.
Write a short note on wildlife.
Answer:
Various plants and animals found in forest are collectively called wildlife. The diverse groups of animals live in forests. Similarly, there are many varieties of plants and trees too, are there in forests. In ancient times, there were comparatively more forests where animals could live with more ease. The number of lions, panthers, rhinos, elephants etc. was exceptionally high. But from the time when human beings started shedding down the forests, the number of animals started decreasing. The number of wild animals is continuously decreasing very rapidly.

Wildlife now needs more protection because of their usefulness and more dependence on it. Wildlife sanctuaries and National Parks have been established for animals where they are provided better safety. Poaching has been strictly banned. Only by protecting wild animals we can help them in breeding and thus can save them from extinction.

Question 3.
What is the importance of forest resources?
Answer:
A. Productive functions

  • Forests provide wood. Indian forests yield valuable timber wood like teak, sal, deodar, shisham etc.
  • Forests provide paper. The conifers and bamboos are used as raw material to prepare paper.
  • Medicinal plants of forests provide medicine of great importance.
  • Forests provide number of products like resins, gums, rubber, food and insecticides.
  • Forests provide shelter to variety of animals.
  • Forests also provide the cork e.g. oak (Quercus).

B. Protective functions
Role of forests in the protection of lands. Forests play a vital role in the life and economy of all tribes living in the forests.

  • Forests prevent erosion of soil by wind and water.
  • Large trees provide shade which prevents the soil from becoming dry and friable during the summer.
  • They check the velocity of rain drops or wind striking the ground and reduce dislodging of the soil particles.
  • The root system of plants firmly binds the soil.

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Question 4.
What are the methods for safety of forests?
Answer:

  • Banning deforestation.
  • Only such trees should be cut those have dried up or have been affected by some diseases. New plants/trees should be grown in place of removed trees.
  • Van Mahotsav should be celebrated. In this week, thousands of new plants/trees should be planted.
  • Newly planted trees should be taken care of.
  • Trees should be counted every year and the target set on Van Mahotsav should be attained.
  • New plans of Van Mahotsav should be followed.
  • Steps should be taken to protect forest from the danger of fire.
  • To protect trees from diseases, chemical and medicines must be used.

Question 5.
Discuss various intermediaries of environmental pollution.
Answer:
Human beings and environment have a strong and unbreakable natural bond. Human beings only either protect or pollute the environment and the consequences of it affect them. Clean and healthy environment is very necessary for human society. Unplanned acts of human beings harms the environment. Smoke from trucks and buses, dirty water of sewerages in rivers and rubbish on roads, pollutes the environment of cities.

Constant increase in population is one of the main reason of environment degradation. Need of houses, clothing and food increases due to increasing population. Natural resources are affected adversely in order to meet these demands like deforestation, uncontrollable use of underground water, industrialisation etc. All these are the major reasons of pollution.

When natural sources do not help properly to clean the environment again, it causes pollution. Industrial mishappenings and illegal setting of factories also help in causing pollution. Over use of harmful chemical is one of its factors. Over exploitation of natural resources also pollutes the environment. Industrial revolution causes water and air pollution. Acid rain is caused due to sulphur oxides which are expelled out from the engines of the vehicles. Ozone layer gets depleted due to excessive use of aerosols.

Waste materials are produced mainly due to various activities which cause environmental degradation. These waste products are very harmful and their effects spread very rapidly.

It is a universal issue now to get rid of it. Recycling and reuse of material only can protect our environment from degradation.
Man is the major factor of environmental pollution and he himself is being affected very adversely because of his own blunders.

Question 6.
Comment on ‘Chipko Movement’.
Answer:
‘Chipko Movement’ was the result of policy to separate people living in mountaineous region from forests. This movement started by incident that took place in ‘Raini’ village in Garhwal located in Himalayan range in 1970. The problem was started between local people and the wood contractors. The contract of shedding down the trees near the village was given to wood contractors. On the specific day, labour of the contractor came to cut down the trees. The local male population was not present at that time but women of that village reached there instantly and hugged the trees and didn’t allow them to cut the trees. Since they stuck themselves to trees and the labour of contractor was forced to stop the work.

Question 7.
Why should coal and petroleum be used carefully?
Answer:
Coal and petroleum are the results of dead and decayed fossils of plants and animals in which hydrogen, nitrogen and sulphur are present along with carbon. On burning these carbon dioxide, water, nitrogen oxides and oxides of sulphur are produced.

On burning them in the inadequate supply of air, carbon monoxide is produced in place of carbon dioxide. All these gaseous products are poisonous in nature. Carbon dioxide is a greenhouse gas. Carbon is present in large amount in coal and petroleum. If complete carbon present in them is not burnt, then availability of oxygen will become abundant on earth and it will change to carbon dioxide. It will lead to global warming of our earth as well. So, coal and petroleum should be used carefully.

Question 8.
How is Ganga river polluted? Comment on its cleanliness plan.
Answer:
Ganga covers the distance of 2500 km from Gangotri situated in Himalaya mountain to Bay of Bengal. It flows from different states with more than one hundred cities due to which it gets polluted.

Following are the types of pollution which are responsible for Ganga’s pollution :

  • Industrial waste.
  • Unprocessed Excreta.
  • Burning the dead bodies near its banks and immersing the remains of dead bodies.
  • Taking bath in Ganga because of certain superstitions.

Cleanliness plan of Ganga. Remains of dead bodies are immersed in the water of Ganga because of traditional customs that is why coliform bacteria is present in it and it goes on increasing in downstream water. Cleanliness plan of Ganga was started in 1985. Who the budget in first step was 462 crores and in second step it was 416 crores. Under this plan 873 million litres water was to be treated daily. To have a control on pollution of Ganga, immediate need is to increase the functioning of this plan.

Question 9.
What are the methods of conserving water resources?
Answer:
Conservation of water resources
For conservation and management of fresh water following methods can be employed :

  • Reducing agricultural water wastage by increasing efficiency of irrigation system.
  • Afforestation and protection of watersheds to improve economy.
  • Formation of artificial clouds, so that a change can be brought in the atmosphere.
  • Changes in the vegetation of a particular area, so that even in the dry season maximum amount of water can be stored. In addition to this, dams should be constructed to stop the drainage of rain water.
  • Control the distribution of water by constructing big dams.
  • Desalinization of sea water and saline ground water.
  • Proper utilization of underground water.
  • Attempt to extract minerals from water.
  • Melt the glaciers and snow for using as a fresh water resource.
  • Regular dredging and desiltation of water bodies.

Question 10.
Discuss various ways of water harvesting.
Answer:
Water harvesting can be undertaken through a variety of ways such as follows :

  • Capturing run off from roof tops.
  • Capturing run off form local catchments.
  • Capturing floodwaters from local streams.
  • Conserving water through watershed management.

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Question 11.
Why use of coal and petroleum should be restricted?
Answer:
Necessity of Judicious Use of Coal and Petroleum. The fossil fuels, coal and petroleum get exhausted and their combustion pollutes our environment, so a judicious use of these resources is necessary.

  • Since coal and petroleum have been formed from biomass, in addition to carbon, these contain hydrogen, nitrogen and sulphur.
  • When these are burnt, the products formed are carbon dioxide, water, oxides of nitrogen and oxides of sulphur. When combustion takes place in insufficient air (oxygen), then carbon monoxide is formed instead of carbon dioxide.
  • Of these products, the oxides of sulphur and nitrogen and carbon monoxide are poisonous at high concentrations and carbon dioxide is a greenhouse gas which leads to global warming.
  • Another way of looking at coal and petroleum is that they are huge reservoirs of carbon and if all of this carbon is converted to carbon dioxide, then the amount of carbon dioxide in the atmosphere is going to increase leading to intense global warmings. Thus, we need to use these resources judiciously.

Question 12.
Explain any four measure for conservation of wild life.
Answer:
Some of the steps involved in the conservation of wild life are :

  • The wild life should be protected in natural habitats (in-situ conservation) as well as in places under human control such as zoological and botanical gardens, genetic re-source centres, culture collection (Ex-situ conservation).
  • The threatened species should be given preference over others in the conservation programme. Among these, the endangered species should get priority over the vulner¬able species, and the latter over the rare species.
  • The habitats of wild relatives of useful plants and animals should be preserved in protected areas.
  • The critical habitats of wild animals should be kept intact.

Short Answer Type Questions

Question 1.
Define Natural resources with example.
Answer:
Natural Resources. Resources which exist naturally in nature and are useful to human beings are called natural resources e.g. air, water, soil, coal, petroleum etc. are natural resources.

Question 2.
Explain the principles of first ‘R’ in 3R’s.
Answer:
First ‘R’ stands for Reduce. It means that we should use the resources in limited exten. For example we can switch off the fans and bulbs when not in use and can save electricity. In the same way by using water in less amount and by getting leaking pipes repaired, we can save water from wastage.

Question 3.
Explain the principle of second ‘R’ in 3R’s.
Answer:
Second ‘R’ stands for ‘recycle. It means that we should reuse plastics, paper, glass and should make these in making useful in our daily life. We should not discard them by throwing in dust bin instead should keep them separately for using again.

Question 4.
What is the importance of third ‘R’ in R’s?
Or
How is ‘reuse’ helpful in the conservation of environment?
Answer:
Third ‘R’ represents ‘ Reuse’. This is considered better than recycling. In recycling some of the energy definitely goes waste. In the process of reusing, same thing can be used again and again. For example the containers and bottles of eatables can be used for storage of other things.

Question 5.
Give in detail the journey of Ganga and discuss how is it getting polluted?
Answer:
Ganga runs its course of 2500 km from Gangotri in Himalayas to Bay of Bengal. It crosses through Uttar Pradesh, Bihar, Bengal and 100 more cities which are responsible for its pollution. Its main reason is that garbage waste and excreta from these cities are made to flow in it. Apart from this , other human activities like bathing, washing clothes, passing the remains of dead people are also the causes of its pollution and toxic and chemical waste from industries have increased its pollution. These industries contribute chemical effluents to the Ganga’s pollution load and toxicity kills fish in large section of the rivers.

Question 6.
How can we control the pollution of river Ganga?
Answer:
Pollution of Ganga can be controlled by the following steps :

  • By not allowing disposal of industrial waste material in the river.
  • By not disposing toxic substances and the dead remains of animals.
  • By not expelling the domestic waste in river water.
  • Avoid washing clothes in the river.
  • By not pouring ash and remains of dead bodies.

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Question 7.
What is recyling? What can we do for it?
Answer:
Old newspapers, books, notebooks, old products made of metals etc. can be easily transformed into other useful products, which is called recycling. Re-cycled product can be used again and again.

We can do the following works for recycling of materials :

  • Buying those things which can be recycled.
  • By using such things which are produced by recycling process.
  • By selling things for recycling before they get completely destroyed.

Question 8.
Write the contribution of Bishnoi community in Rajasthan to protect environment.
Answer:
Bishnoi community of Rajasthan made applaudable efforts to protect forests and wildlife which has now become a part of their traditional culture. In 1731, in Khejreli village near Jodhpur, 363 people sacrificed their lives to protect ‘Khejri’ trees. This is why the Government of India has instituted an Amrita Devi Bishnoi National Award’ for wild life conservation in memory of Amrita Devi.

Question 9.
“The human intervention has been very much a part of the forest landscape’— what should be the nature and limit of intervention to control over it?
Answer:
We should certainly make some arrangements to control over the nature and limitation of this intervention. Forest resources should be used in such a way that environment and development both may get advantage from these. Local people should get more of its advantage where environment is conserved. It is a decentralisation system that can help both monetary development and environmental conservation. Environment cannot be accepted just as a collection of plants and animals. It is a complex and complicated system. We have many natural resources for the use of it. We must use all these resources very carefully for our financial and social development.

Question 10.
What did Chipko Movement teach to the government and people? Explain.
Answer:
Chipko Movement spread very rapid in various communities. Many social organisations and media also played a vital role in it. It compelled the government to rethink about the decisions needed to be taken in use of forest resources. People by their experience learnt that deforestation not only affects the availability of trees but also quality of soil and water level too gets spoiled. Participation of local people in management of forests must be encouraged.

Question 11.
Explain with an example the role of people in forest management.
Answer:
In 1972, the forest department of West Bengal made some changes in their policy because of getting failure in reviving the degraded Sal forests. Those sal were destroyed in south-west regions. They started their movement at Madinipura in the region of Arabari. A far sighted forest officer of the department A.K Banerjee. encouraged villagers to join the movement and with their help they protected badly degraded sal forests of about 1272 hectares area.

Question 12.
What are the three main problems in constructing of big dams?
Answer:

  • Social problems: Large number of people are forced to migrate and they get affected badly. They have to leave their houses and business. Farmers are forced to leave their agricultural lands.
  • Economic Problems: A huge amount of public money is used without generation of proportionate benefits.
  • Environmental Problems: Deforestation is taking place on large scale. Bio-diversity is adversely affecteu and environmental problems are arising enormously.

Question 13.
What is the importance of water shed management?
Answer:
More importance is given to scientific soil and water conservation to increase the biomass production in water shed management. Its main importance is to develop primary sources of land and water such that secondary resources of plants and animals may not cause ecological imbalance.

Question 14.
What are the advantages of underground water?
Answer:

  • It does not evaporate to mix in atmosphere.
  • Vegetation Plants animals are not present in it.
  • It improves the water level.
  • It provides dampness to plants.
  • It does not get polluted due to the presence of living beings.

Question 15.
How can underground water level be recharged in largely level terrain?
Answer:
In largely level terrain water harvesting structures are made. These are mainly crescentshaped earthen embankments. These may be low, straight concrete check dams built across seasonal flooded gullies. Rain water gets stored in Monsoon rains behind the structures. Most of the water dries up in six months after monsoons. It recharges the ground water beneath.

Question 16.
What are fossil fuels and how are they made? Give two examples of these.
Answer:
The remains of animals and plants got compressed under the crust of earth in the absence of oxygen million of years ago. Thus they could not get oxygen. Under the crust neither oxidation of these was possible nor destruction but because of the internal pressure water and volatile substances squeezed out. These substances are termed fossil fuels. Actually fossil fuels are the molecules of carbonic compounds. These are the results of degradation of biomass millions of years ago. The examples of fossil fuel are coal, petroleum and natural gas.

Question 17.
Water is very essential for survival of life’. Justify this statement.
Answer:
Water is essential due to following reasons :

  • It takes part in all chemical reactions taking place in our body.
  • It maintains the temperature of body.
  • It is important for body to carry nutrients to all parts of the body.
  • It helps in excretion of organic waste from the body.
  • It is important for transportation of substances.
  • Irrigation, industries and electricity are totally dependent on water.

Question 18.
Write some major means of water conservation.
Answer:
We can conserve water by :

  • Using water for irrigation.
  • Flood control, hydrological survey and construction of dams.
  • Recharging of underground water and avoiding its wastage.
  • Transformation of high water levels into low water levels.
  • Safety of soil to avoid soil erosion.

Question 19.
Mention the names of air pollutants.
Answer:
The main air pollutants are :

  • Carbon monoxide
  • Carbon dioxide
  • Oxides of sulphur and nitrogen
  • Compounds of flourides
  • Hydrocarbons

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Question 20.
Write some methods by which pollution can be controlled.
Answer:

  • By getting knowledge of the causes and control on pollution.
  • By installing the control devices in factories to check the air pollution.
  • By recycling the waste products.
  • Disposal of excreta and expelled waste material in correct way.
  • By using Gobar gas plants.

Question 21.
What is the role of increasing population in destruction of natural resources?
Answer:
Population is increasing constantly due to which human needs are increasing day-by-day. To meet these requirements natural resources are being continuously exhausted. Natural resources are available in large amount but even then these are limited because population has risen at its verge. Our resources are very limited to meet the needs of increasing population. If the monster of increasing population grows at this rate then it will be very difficult to maintain balance between the natural resources and ecology.

Question 22.
Give five points to control pollution.
Answer:
Pollution can be controlled in following ways :

  • Gobar gas plants should be installed.
  • Bio-degradable substances should be disposed in pits.
  • Waste material should be recycled.
  • Excreta and disposal matter should be disposed of in a correct way.
  • CNG should be used in automobiles.

Question 23.
What are the harmful effects of deforestation?
Answer:
If rate of deforestation is more than the rate of afforestation, then the number of trees will reduce with the passage of time. Trees release water vapours in large amount during transpiration and clouds are formed with the help of these. Rainfall is always less in the area where trees are less in number. Due to this the fertile lands convert into deserts. Deforestation slowly causes removal of upper fertile surface of soil that gets carried away through rain water to rivers ultimately.

Question 24.
How can coal and petroleum be saved for long time?
Answer:
Use of coal and petroleum depend on the quality of machines. In vehicles used for transportation consume excess fuel. Scientists have been researching for the complete combustion of fuel. Efforts are being made to get such fuels having more efficiency, less pollution and capacity for storage of enhanced period.

Question 25.
What are the problems faced in the construction of big dams?
Answer:

  • Large numbers of forest, vegetation and bio diversity are lost.
  • Migration of people causes unstability and mental tension.
  • Migrated persons face number of social and economic problems.
  • Benefits are less than the money spent in constructing big dams.

Question 26.
Write difference between National Parks and Animal sanctuaries.
Answer:

National Parks Animal Sanctuaries
1. These provide shelter to special wild animals like cheetah, rhino, lion, etc. 1. Animals are protected in natural environment.
2. These are spread over 100 to 50C kilometres of area. 2. These are spread over 500 to 1000 sq. kilometres of area.
3. Strong walls are erected around these. 3. Tall and high fenced temporary walls are erected around these.

Question 27.
What are the harms caused by burning of fossil fuels?
Answer:

  • Burning of fossil fuel produces harmful gases like CO2, CO, SO2, NO2, etc. are produced.
  • Many respiratory problems are caused due to air pollution.
  • Chances of skin problems increase.
  • Burning sensation is felt in the eyes.

Question 28.
How does rate of development affect the environment? Explain.
Answer:
The rate of development is always beneficial but at the same time it affects the environment. Deforestation is resulted due to urbanisation. Land suitable for agriculture is used for constructing factories. Smoke expelled through chimneys of factories pollutes the air and leaves a harmful effect on health of all living beings. Due to urbanisation cities expand resulting in deleting of villages due to which agricultural land is extincting. Transportation and telecommunication are increased due to which roads and railway need more land. Deforestation is needed for these.

Question 29.
What are uses of water shed management?
Answer:

  • To face the situation of drought.
  • To get rid of floods.
  • Long life of dams and water reservoirs.
  • For conservation of water.
  • To make water available for irrigation for the whole year.

Question 30.
What are Kulhs? How were these managed?
Answer:
Kulhs are the local irrigation canals evolved by the people of Himachal Pradesh about 400 years ago. The water of natural waterfalls and flowing in streams w as diverted into man-made channels which took this water to numerous villages down the hillside. The management of water flowing in these kulhs was based on a common agreement among the villages. During planting season, watjr-was first of all supplied to the village farthest away from the source of Kulh. The water flow in Kulhs was managed by two-three persons who were paid by the villagers. Apart from irrigation these Kulh’s also percolated into the soil that helped the springs to feed at various points. Government took over these kulhs later but after some time irrigation department lost control and these became non-functional.

Question 31.
What was the losses of inequality in distribution of water?
Answer:
Canal systems leading from dams transfer water from one place to the other distant places. Indra Gandhi canal has helped a big part of Rajasthan to get green now but due to unequal distribution of water and poor management many people could not get benefits from this system. Water is not equally distributed due to which people living near the water source are able to grow crops like sugarcane and wheat which need water in large amount whereas people living away cannot get sufficient amount of water. They cannot grow crops of their choice.

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Question 32.
Find out the traditional methods of water storage in your nearby locations.
Answer:
The water harvesting has been a traditional system in India. In Rajasthan by Khad, tanks and Nadis, in Maharashtra by bandharas and Tals, in Madhya Pradesh and Uttar Pradesh by Bundhis the water is harvested. In Bihar Aahar and Pynes, in Himachal Pradesh Kulhs, in Jammu region Ponds and in Tamil Nadu by Eris, in Kerala by surangams and in Karnataka by Kattas rain water is harvested.

Question 33.
Explain a traditional Rain water Harvesting system.
Answer:
Water harvesting is a traditional system in India. In Rajasthan by Khadin, in, Maharashtra by bandharas and Tals, in Madhya Pradesh and Uttar Pradesh by Bundhis, in Bihar by Aahar and Pynes, in Himachal Pradesh by Kulhs and in Jammu regions of Jammu by ponds the rain water in harvested and is still in use by people living there. Rain water is stored in dams and is used for different persons. This water becomes the reason of increasing water level in wells.
PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources 1
Traditional water harvesting system-khadin system

Very Short Answer Type Questions

Question 1.
What is Pollution?
Answer:
Substances which are found in natural state or when they get mixed with dust or toxic substances is called as pollution.

Question 2.
Write five Natural resources.
Answer:

  1. Forest
  2. Wildlife
  3. Water
  4. Coal
  5. Petroleum.

Question 3.
What are 3R’s?
Answer:

  1. Reduce
  2. Recycle
  3. Reuse.

Question 4.
Write things which can be recycled?
Answer:
Plastic, glass, paper and things made of metals.

Question 5.
Which energy do we get on earth?
Answer:
Solar energy that we get from the sun.

Question 6.
Write full form of CFC.
Answer:
Chloro-Fluoro Carbons.

Question 7.
Name the living beings responsible for biodiversity.
Answer:
Bacteria, fungi, ferns, flowers, plants, nematodes, insects, birds, reptiles.

Question 8.
When was Ganga cleanliness plan enacted?
Answer:
In 1985.

Question 9.
What is coliform?
Answer:
A coliform is a group of bacteria which is found in human intestines due to water pollution.

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Question 10.
Write the origin of river Ganga and its course of run.
Answer:
Ganga runs its course of over 2500 km from Gangotri in Himalyas to Ganga Sagar in the Bay of Bengal.

Question 11.
What do we get from sea water?
Answer:
We get iodine from sea water.

Question 12.
How do get solar energy?
Answer:
We get solar energy from sunlight which comes directly from sun and we intake them through plants.

Question 13.
Name three toxic gases.
Answer:
Nitrogen oxide (NO), Sulphur dioxide (SO2), Carbon monoxide (CO).

Question 14.
Name three trees which are found in forests.
Answer:
Pine, Eucalyptus, Timber.

Question 15.
How does the growth of grass stop in Alpine forests?
Answer:
Grass grows very tall and it falls down on ground which haults the growth of grass.

Question 16.
When and where Chipko Andolan was started?
Answer:
Chipko Andolan was started in village Reni of Garhwal in 1970.

Question 17.
Name three major resources of minerals.
Answer:
Coper, Iron and Manganese.

Question 18.
Write three renewable sources of energy.
Answer:
Wood, Water and Solar energy.

Question 19.
Write two non-renewable sources of energy.
Answer:
Coal and Petroleum.

Question 20.
Name two traditional sources of energy.
Answer:
Fossil fuel and flowing water.

Question 21.
Name two major constituent gases of atmosphere.
Answer:

  1. Nitrogen 78%,
  2. Oxygen 21%.

Question 22.
What is universal indicator?
Answer:
Litmus paper is called as universal indicator.

Question 23.
What is measured by litmus paper?
Answer:
pH is measured easily with the help of litmus paper.

Question 24.
Why is reuse better than recycle?
Answer:
In recycling some amount of energy is wasted.

Question 25.
Who is the main stakeholders of forests when we think about conservation of forests?
Answer:
The main stakeholders are people who live in and around the forests and are dependent on forest for different needs.

Question 26.
What is the other name of timber?
Answer:
The other name of timber is carpet-wood.

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Question 27.
For what forests are considered as source of industries?
Answer:
For raw materials.

Question 28.
Mention two industrial requirements those lead to deforestation.
Answer:
Construction of roads and dams.

Question 29.
On what rains of our country are dependent?
Answer:
Monsoon. The duration of rainy season is limited for a few months.

Question 30.
What is the ancient system of water harvesting in India?
Answer:
Dams, ponds and rivers.

Question 31.
What are Kulhs?
Answer:
400 years ago a traditional harvesting system was developed in Himachal Pardesh canal water. These were called as Kulhs.

Question 32.
If these natural resources are used at the present rate, for how long will they exist?
Answer:
Petroleum will be available for about next 40 years and coal resource for next 200 years.

Question 33.
On what pressure is always maintained in watershed arrangement?
Answer:
Soil and water management.

Question 34.
Name two categories in which waste substance can be divided. Which among these two is comparatively more harmful?
Answer:

  1. Biodegradable substances.
  2. Non-biodegradable substances. Non-biodegradable substances are comparatively more harmful.

Question 35.
What is the main reason behind the establishment of National Parks and sanctuaries?
Answer:
To protect wildlife.

Question 36.
Write two harmful effects caused by industries on air setting up heavy industries on local climate.
Answer:

  1. Air pollution.
  2. Increase in temperature of atmosphere.

Question 37.
Write the main cause of global warming.
Answer:
High amount of CO2 a green house gas, in the atmosphere due to burning of fossil fuel is resulting in global warming.

Question 38.
Name two renewable natural resources.
Answer:

  1. Forests and
  2. Water.

Question 39.
Name any one endangered plant species.
Answer:
Podophythum.

Question 40.
Name the person who started Appiko movement in South.
Answer:
Pandu Kumar Hegde started appiko movement in Karnataka in 1983.

Multiple Choice Questions

Question 1.
What is the desired minimum total coliforin count level in the Ganga?
(A) 500 MPN/100 ml
(B) 600 MPN/100 ml
(C) 1000 MPN/100 ml
(D) 1200 MPN/100 ml.
Answer:
(A) 500 MPN/100 ml

Question 2.
Chipko Andolan was started by:
(A) Amrita Devi Bishnoi
(B) H.N. Bahuguna
(C) Sunder Lai Bahuguna
(D) A.K. Bannerji.
Answer:
(C) Sunder Lai Bahuguna

Question 3.
Which of the following is/are example(s) of people partici pation in the management of forests?
(A) Chipko Andolan
(B) Arabara forest range of Midnapur
(C) Appiko movement
(D) Khejri tree movement.
Answer:
(B) Arabara forest range of Midnapur

PSEB 10th Class Science Important Questions Chapter 16 Management of Natural Resources

Question 4.
Which of the following represents the regulative function of forest?
(A) Storage and release of gases
(B) production of wood
(C) production of essential oils
(D) conservation of soil and water.
Answer:
(D) conservation of soil and water.

Question 5.
Extensive planting of trees to increase forest cover is called :
(A) afforestation
(B) agroforestry
(C) deforestation
(D) social forestry.
Answer:
(A) afforestation

Question 6.
Enviromnent is formed of:
(A) only biotic component
(B) Only abiotic
(C) Both (A) and (B)
(D) None of above.
Answer:
(C) Both (A) and (B)

Question 7.
Environment day falls on:
(A) 28th Feb
(B) 23rd March
(C) 5th June
(D) 14th Nov.
Answer:
(C) 5th June

Question 8.
Joint Forest management is an example of:
(A) Political equality
(B) Participatory approach
(C) Food stabilization
(D) Economic equality.
Answer:
(B) Participatory approach

Fill in the Blanks :

Question 1.
Chipko Andolan was started by _________ in 1970.
Answer:
Sundar Lai Bahuguna.

Question 2.
Ganga Action Plan was launched in _________
Answer:
1985.

Question 3.
_________ (coal and petroleum) are important sources of energy.
Answer:
Fossil Fuels.

Question 4.
Three R’s to save the environment are Reduce, _________ and _________
Answer:
Recycle, Reuse.

Question 5.
_________ is the ultimate source of energy.
Answer:
Sun.

Question 6.
Tehu Dam is built on _________
Answer:
River Ganga.

Question 7.
Forests provide _________ and plants.
Answer:
Wood, medicinal.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

This PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ In a chemical reaction, old bonds in the reactants are broken forming new bonds to give products.

→ A chemical equation represents a chemical reaction.

→ By using chemical formulae instead of words, chemical equations can be made more useful and concise.

→ According to the law of conservation of mass matter (or Mass) can neither be created nor destroyed in a chemical reaction.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ If the number of atoms of each element is the same on both sides of the arrow in a chemical reaction then the chemical equation is a balanced equation.

→ The method used to balance chemical equations is known as the Hit-and-Trial method since we make trials to balance the equation by using the smallest whole number coefficient.

→ The solid, gas, liquid, and aqueous states of reactants and products are represented by the notations: (s), (g), (l), and (aq) respectively.

→ When reactants and products are present as solutions in water then the word aqueous (aq) is written.

→ When (g) is written with water, it means that water is present in the form of vapour.

→ A reaction in which two or more reactants combine to form a single product is known as a combination reaction.

→ The chemical formula for marble is CaCO3.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ After two three days of whitewashing, calcium carbonate is formed which gives a shiny finish to the walls.

→ We get energy from food.

→ During digestion, food is broken into fine particles of simpler substances.

→ The decomposition of vegetable matter into compost is an example of an exothermic reaction.

→ A reaction in which a single reactant breaks down to give simpler products is called a decomposition reaction.

→ On heating, crystals of ferrous sulfate crystals lose water, and their color changes.

→ NO2 fumes are brown in colour.

→ The white colour of silver chloride changes into a grey colour in sunlight.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ The chemical reactions in which energy is given out are called exothermic reactions.

→ Those reactions in which energy is absorbed are known as endothermic reactions.

→ Those reactions in which there is an exchange of ions between the reactants are called double displacement reactions.

→ Those reactions in which precipitates are formed are known as precipitate reactions.

→ If in a reaction one of the reactants gets oxidized and the other gets reduced, then such a reaction is called a redox reaction.

→ In a reaction, a substance is oxidized when there is a gain of O2 or a loss of H2 in it.

→ A substance is reduced when it gains H2 or loses O2.

→ When a metal comes in contact with acid or moisture around it, gets corroded and the process is called corrosion.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ Examples of corrosion are black coating on silver and green coating on copper.

→ Oxidation of oils and fats become rancid and their taste and smell change.

→ To slow down the oxidation process of food materials these are kept in air-tight containers.

→ Chemical change: It is a reaction in which new substances are formed. It is called a chemical change.

→ Chemical reaction: A process in which chemical change takes place is called a chemical reaction.

→ Reactants: Those substances which take part in a chemical reaction are called reactants.

→ Products: Those substances which are formed in a chemical reaction are called products.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ Combination reaction: It is a chemical reaction in which two or more two substances combine to form a single substance.

→ Decomposition reaction: It is a chemical reaction in which a molecule breaks into molecules of simpler substances.

→ Displacement reaction: A reaction in which a substance displaces another substance is called a displacement reaction.

→ Double displacement reaction: This is a reaction in which there is a mutual exchange between two different atoms or groups of atoms.

→ Neutral solution: When an acid and a base are mixed in a proper proportion, then we get a neutral solution.

→ Neutralisation reaction: When we get salt and water as the only products by mixing acid and base, then such a reaction is known as a Neutral reaction.

→ Oxidation: A substance is oxidized when there is a gain of oxygen or a loss of hydrogen in the substance.

→ Reduction: A substance is reduced when there is a loss of oxygen and a gain of hydrogen in the substance.

→ Redox reaction: A reaction in which oxidation and reduction both take place simultaneously is called a redox reaction.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ Exothermic reaction: Those reactions in which heat is produced along with the products are called exothermic reactions.

→ Endothermic reactions: Those reactions in which heat is absorbed are called endothermic reactions.

→ Precipitation reactions: When two solutions are mixed and due to reaction between them a white coloured substance (or some other colour) is formed which is insoluble in water, then this is called a precipitation reaction.

→ Fermentation: The change of carbonic substances with the help of microorganisms or enzymes into simple carbonic substances is called fermentation.

→ Rancidity: When fat/oil-containing food materials are left for a long time then due to oxidation there is a change in their smell and taste, this change is called rancidity.

→ Reducing agent: That substance that gets oxidised itself or reduces the other substances by giving electrons is called a reducing agent.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ Oxidizing agent: That substance that gets reduced itself or oxidizes the other substances by gaining electrons is called an oxidizing agent.

PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers

This PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers will help you in revision during exams.

PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers

→ During the 19th and 20th centuries, many changes came in the European society and it is said that Sociology originated to study such changes.

→ From the 17th-19th centuries, many philosophers wrote new books which gave a great contribution to the emergence of sociology. Montesquieu and Rousseau are quite important among them.

→ Auguste Comte was a French philosopher and is considered as the Father of Sociology.

→ He wrote a book ‘The Course on Positive Philosophy’ in which in 1839, he used the word ‘Sociology’. He called it a science of society.

→ Comte gave the theory of Positivism and said that social phenomenon can also be understood with scientific explanation and positivism is that method.

PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers

→ So, positivism is the systematic method of observation, experience, comparison, and historical method with which society can be scientifically studied.

→ Comte studied different societies and said that to reach the present stage, society had to cross through three stages and these stages are the Theological stage, Metaphysical stage, and Positivistic stage. This is Comte’s law of three stages.

→ Karl Marx was a German Philosopher who is known for his views given on class and class struggle.

→ The concepts of communism and socialism were also given by Karl Marx.

→ Marx was of the view that the history of society, is the history of class struggle.

→ There exist two classes in all the societies-capitalist class which owns all the means of production and labour class which is not having anything to sell except its labour.

→ There is the existence of conflict between the both to get more and this is known as class struggle.

PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers

→ Emile Durkheim is also known as one of the founding fathers of sociology.

→ He tried to establish sociology as a science. He was the first professor in the subject of sociology.

→ Durkheim gave a great contribution to the subject of sociology and some of the important concepts given by him are the concept of Social Fact, Theory of Suicide, the theory of Division of Labour, the Concept of Religion, etc.

→ Durkheim was of the view that the concept of division of labour existed in society right from ancient times.

→ The nature of society is determined due to the division of labour.

→ Max Weber is one of the important sociologists and founding fathers of sociology.

→ Like Marx, he was also a German Philosopher.

→ He gave many concepts to sociology such as the concept of social action, Verstehen, Protestant Ethics and Spirit of Capitalism, Authority and its types, Bureaucracy, etc.

PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers

→ Class: Group of people whose means of production are common.

→ Authority: It is a form of power supported by the norms of a social system and accepted as legitimate by those who participate in it.

→ Social Action: It is an act that cares about the actions and reactions of individuals. If the acting individual takes account of others’ behaviour, it is social.

→ Class Consciousness: The awareness among members of a class about their common motives.

→ Class Struggle: There exists a conflict of interests between capitalist and labour classes. This conflict of interests becomes a reason for class struggle. When class consciousness increases among the people, class struggle also increases.

→ Positivism: In positivism, it is considered that society acts according to certain rules which can be discovered.

→ Mechanical Solidarity: The sense of unity among the members of a homogeneous society is called mechanical solidarity.

PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers

→ Organic Solidarity: In many societies, people have differences among them and that’s why they depend upon each other. The unity which exists in such a society is known as organic solidarity.

PSEB 11th Class Sociology Notes Chapter 11 Social Change

This PSEB 11th Class Sociology Notes Chapter 11 Social Change will help you in revision during exams.

PSEB 11th Class Sociology Notes Chapter 11 Social Change

→ Change is the law of nature. There is nothing in this world that has not yet changed. Even nature changes itself from time to time.

→ When change comes in different parts of society and the change affects the structural change comes in the ways of living of the people.

→ There are many features of social change such as it is a universal process, speed of changes is different in different societies, it is community change, no prediction regarding change is possible, it is the result of many interactions, it can be planned as well as unplanned, etc.

PSEB 11th Class Sociology Notes Chapter 11 Social Change

→ There are many types of social change such as evolution, development, progress, and revolution.

→ Many a time these words are used for each other but in Sociology, they are very much different from each other.

→ The meaning of evolution is equal change internally. This is a very slow process and social institutions change from simple to complex.

→ Development is also an aspect of social change.

→ When change comes in anything in the desired direction, it is known sis development.

→ Different sociologists have given different bases of development.

→ Progress is another type of social change. It means to move towards achieving objectives.

→ Progress is the efforts made to achieve objectives which is definite and which get scope ration from social values.

PSEB 11th Class Sociology Notes Chapter 11 Social Change

→ Revolution brings a sudden and fast change in society with which old structure comes to an end and new structure comes forward.

→ Many a time people become so dissatisfied that they stand up against the system. It is known as revolution.

→ The revolution of 1789 A.D. in France was a change of such type.

→ Many factors influence the direction and speed of social change such as natural factors, beliefs, and values, social reforms, demographic factors, technological factors, educational factors, etc.

→ Diffusion: The process by which cultural traits spread from one culture to another.

→ Innovation: Introduction of new ideas, techniques, etc., and better use of existing ideas and technology.

→ Social Change: Change in the functions of social structure and social system.