Selina solutions concise physics class 6 icse Solutions for Chapter 1 matter

Q1) Write true or false for each statement.

(a) The molecules of each substance are identical.

(b) The intermolecular forces are effective at all distances between the two molecules.

(c) The molecules in a substance are in random motion .

(d) In a gas, the molecules can move anywhere in space.

(e) The liquids are less viscous than the gases.

Q2) Fill in the blanks

(a) All the molecules of a substance are __________.

(b) The intermolecular spacing is _________in the solids, _________ in liquids and __________ in gases

(c) The molecular motion in liquid and gas is in zig zag path

(d) In a solid, the molecules __________. but they remain at their fixed positions.

(e) The intermolecular forces are the weakest in __________.

(f) A solid exerts pressure __________.

(g) The gases are least ______dense.

(h) A solid is _______ rigid.

Q3) Select the corect alternative:

(a) The diameter of a molecule is approximately

1. 1cm

2. 10cm

3. 10^{-10}m

4. 1m

(b) The intermolecular forces are strongest in

1. Solids

2. Liquids

3. Gases

4. Both (i) and (ii)

(c) The molecules

1. In solid, liquid and gas, move freely anywhere

2. In a solid, move freely within its boundary

3. In a liquid, move within its boundary

4. In a gas, move only within its boundary

(d) The solids are

1. More dense

2. Less dense

3. Least dense

4. Highly compressible

(e) The intermolecular forces in liquids are

1. As strong as in solids

2. Stronger than in solids

3. Weaker than in solids

4. Weaker than in gases

Q4) Match the following columns :

Q1) Define matter. What is its composition ?

Q2) Name the three states of matter.

Q3) What is a molecule ?

Q4) What is the approximate size of a molecule ?

Q5) One litre of water has 6.02\times10^{26} molecules. Estimate the size of a molecule.

Q6) What do you mean by inter-molecular spacing ?

Q7) Describe a simple experiment to illustrate the existence of inter-molecular spacing.

Q8) What do you mean by inter-molecular forces ?

Q9) What are the forces of cohesion and adhesion ?

Q10) State three characteristics of molecules of matter.

Q11) State the approximate spacing between two molecules of a matter.

Q12) How do the solids , liquids and gases differ in their following properties.

(a) Size

(b) Shape

(c) Density

Q13) The molecules in a substance are in motion. What type of path do they follow ?

Q14) Describe a simple experiment to illustrate that molecules are not at rest , but they constantly move.

Q15) Write down five general properties of solids, liquids and gases.

Q16) Give the molecular model for a solid and use it to explain why a solid has a definite volume and a definite shape.

Q17) Describe the molecular model for a liquid. How does it explain that a liquid has no definite shape, but has a definite Volume ?

Q18) A gas has neither a definite volume nor a definite shape. Describe the molecular model to explain it.

Q19) Distinguish between the three states of matter – solid, liquid and gas on the basis of their molecular models.

Q20) Distinguish between solids, liquids and gases on the basis of their following properties :

(a) Compressibility

(b) Fluidity

(c) Rigidity

(d) Expansion on heating

Q21) What do you mean by the change of state of matter ? Explain :

(a) the change of a solid into a liquid at a constant temperature, and

(b) the change of a liquid into a gas at a constant temperature.