Matter Class-8 Dalal ICSE New Simplified Chemistry Dr Viraf J Dalal Middle School Allied Publishers Solutions. Chapter-1 . We Provide Step by Step Solutions of Exercise/Lesson -1 The Matter with Objective Type Questions, Fill in the blnks and Give reason of Dr Viraf J Dalal Middle School Chemistry Allied Publishers. Visit official Website for detail information about ICSE Board Class-8.

## Matter Class-8 Dalal New Simplified ICSE Chemistry Middle School Allied Publishers Solutions

Exercise-1

Question 1.
Explain the meaning of the term ‘matter’.
Anything that has mass, occupies space and can be felt by the sense organs are called matter.

Question 2.
Matter in any state is composed of small particles – molecules, atoms or ions. Differentiate the terms above in Italics.
Molecules : the smallest particle of a substance that can exist separately , e.g. N2, Br2, Cl2 are molecules.
Atoms :  the smallest particle of an element which can take part in all chemical reaction and is  the basic unit of matter, e.g. Fe, Au, Hg are example of atoms.
Ions : atom or a group of atoms which has a  charge due to loss or gain of electrons, e.g. Ca2-, Na1+, Cl1-– are ions.

Question 3.
Differentiate between the-two characteristics of matter – ‘mass’ & ‘weight’.
Mass :

1. amount of matter in a body and never change place to place
2. It is measured in Kilograms (kg) by beam balance

Weight :

1. It is the force of attraction that pull of gravity on a body.
2. It is measured in Newtons (N)and change value place to place

Question 4.
State which of the three states of matter Le. solids, liquids or gases – have

(a) No definite volume
(b) A definite shape
(c) High density
(d) No free surfaces
(e) Particles – which diffuse very easily.

(a) Gases
(b) Solids
(c) Solids
(d) Gases
(e) Gases

Question 5.
State the main postulates of the kinetic theory with special reference to –

(a) Inter-particle space
(b) Inter-particle attraction
(c) Energy possessed by particles of matter.

(a) Inter-particle space : The particles of matter are arranged in a way such that they have spaces existing between them. i.e. inter molecular space.
(b) Inter-particle attraction :  particles of matter attract each other with a force of attraction which is inversely proportional to distance

(c) Energy possessed by particles of matter :  particles are in continuous motion, and has mass so they, possess energy called kinetic energy.

Question 6.
State in which of the following examples ie. a piece of wood, water, a light gas is the

(a) Inter-particle space maximum
(b) Inter-particle attraction maximum
(c) Energy possessed by particles of matter, very large.

(a) A light gas
(b) a piece of wood
(c) a light gas

Question 7.
In which of the three states of matter – solids, liquids or gases is the movement of atoms about their own position. Give a reason for the same.

Solid

Reason–  because of Minimum Inter Particle space and very strong inter – particle attraction among atoms.

Question 8.
‘Inter-particle attraction between atoms of gases is very weak’. State five properties of gases which correlate as a consequence of the weak inter-particle attraction between particles of gases.
The five properties of gases which correlate as a consequence of the weak inter-particle attraction between particles of gases are :

• Gases have no definite volume.
• It have no definite shape.
• They have enough space between molecules
• they are compressible
• they have low density
• the diffuse faster

Question 9.

What is inter-conversion of matter. Give the meaning of the terms involved in inter-conversion of matter

(a) Melting
(b) Vaporisation
(c) Liquefaction or condensation,
(d) Solidification or freezing
(e) Sublimation.

Interconversion of matter :
“Change of state of matter from one state to another state and back to its original state is called inter-conversion of matter.”

(a) Melting–Conversion of a solid into a liquid on heating ex–. ice to water.

(b) Vaporisation–Conversion of a liquid into vapours (or gas) on heating ex–. water to water vapour.

(c) Liquefaction or condensation– Conversion of vapor (or gas) into a liquid on cooling ex-. water vapour to water.

(d) Solidification or freezing– Conversion of a liquid into a solid ex-. water to ice.

(e) Sublimation.–Conversion of a solid directly into  gas state ex-. Naphthalene sublimes at room temperature.

Question 10.

Draw a labelled schematic diagram representing the terms (a) to (e) involved in the inter-conversion of matter.
(a) Melting

(b) Vaporisation

(c) Liquefaction or condensation

(d) Solidification or freezing

(e) Sublimation

Question 11.
With reference to inter-conversion of matter – on the basis of kinetic theory – explain in brief the conversion of :

(a) A solid into a liquid
(b) A liquid into vapour [or gas]
(c) Vapour [or gas] into a liquid
(d) A liquid into a solid

With special reference to inter-particle space & inter particle attraction at the different stages of conversion.
(a) when A solid convert into a liquid :

• Inter-particle space-increases.
• Force of attraction -decreases.
• Collision-increases .
• Kinetic energy increases
• Heat energy is absorbed by the molecules and stored in the form of potential energy.

(b) When A liquid change into vapour

1. Kinetic energy increase.
2. Inter-particle space-increases.
3. Force of attraction-decreases
4. Collision-increase

(c) When a Vapour change into a liquid :

1. Kinetic energy decrease
2. Inter-particle space-decreases considerably.
3. Force of attraction -increases.
4. Collision-decrease

(d) When A liquid change into a solid :

1. Kinetic energy decrease.
2. Inter-particle space-decreases.
3. Force of attraction-increases. Particles are not in position to be free.
4. Collision-decreases.

Question 12.

On the basis of kinetic theory explain why, ammonium chloride sublimes and goes from solid state directly into vapour state.
Ammonium Chloride sublimes and It convert from solid state directly into vapour state because if low inter-particle attraction.
Question 13.

State the ‘law of conservation of mass’. State the main points of Landolt’s experiment for experimental evidence of the law.
Law of Conservation of Mass : “Mass can not be created nor destroyed during reaction.”

Landolt’s experiment : To explain the law of conservation of mass. Two solutions – NaCl in limb A and AgNO3 sol. in limb B were taken in U-shaped tube and weighed.

Now tube was tilted so that two solutions get mixed and react with each other to form new products. Tube is weighed again after cold

Conclusion-
Weight after reaction was found to be same as before reaction.

Hence confirming the Law of Conservation of Mass

### OBJECTIVE TYPE QUESTIONS

Matter Class-8 Dalal New Simplified ICSE Chemistry Middle School Allied Publishers Solutions

Q.1. Select the correct answer from A, B, C, D & E for each statement given below:
A: Solid
B: Vaporization
C: Ion
D: Gases
E: Heat

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