Allied solutions simplified middle school chemistry class 8 Solutions for Chapter 1 matter

Q1. Explain the meaning of the term ‘matter’.

Q2) Matter in any state is composed of small particles - molecules, atoms or ions. Differentiate the terms above in italics.

Q3) Differentiate between the two characteristics of matter - ‘mass & weight’

Q4) State which of the three states of matter i.e. solid, liquid & gas have -

(i) No definite volume

(ii) A definite shape

(iii) High density

(iv) No free surfaces

(v) Particles - which diffuse very easily

Q5) State the main postulates of kinetic theory with special reference to -

1. Interparticle space
2. Interparticle attraction
3. The energy possessed by particles of matter

Q6) State in which of the following examples, i.e. a piece of wood, water, light gas is the

1. Interparticle space maximum
2. Interparticle attraction maximum
3. The energy possessed by particles of matter, very large

Q7) In which of the three states of matter - solids, liquids & gases is the movement of atoms about their own position. Give a reason for the same.

Q8) ‘Inter-particle attraction between atoms of gases is very weak’. State five properties of gases which correlate as a consequence of the weak interparticle attraction between particles of gases.

Q9) What is the interconversion of matter? Give the meaning of the terms involved in inter-conversion of matter.

1. Melting
2. Vaporisation
3. Liquefaction or Condensation
4. Solidification or Freezing
5. Sublimation

Q10) Draw a labelled schematic diagram representing the terms (a) to (e) involved in the interconversion of matter.

1. Melting
2. Vaporisation
3. Liquefaction or Condensation
4. Solidification or Freezing
5. Sublimation

Q11) With reference to inter-conversion of matter - on the basis of kinetic theory - explain in brief the conversion of :

1. A solid into a liquid
2. A liquid into a vapour
3. Vapour (or gas) into a liquid
4. A liquid into a solid

Q12) On the basis of kinetic theory explain why ammonium chloride sublimes and goes from solid-state directly into the vapour state.

Q13) State the ‘law of conservation of mass.’ State the main points of Landolt’s experiment for experimental evidence of the law.

Q1) 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

1. An atom or group of atoms - having a resultant charge.
2. An atom or group of atoms - having a resultant charge.
3. In Landolt’s experiment - the form in which the chemical energy stored up in the reactants - is released.
4. The process of change of a liquid into vapour, (gas) on heating.
5. The state of matter, where the inter-particle attraction between particles is maximum.

Q2) With reference to the liquid state of matter, answer the following.

1. On heating, the liquid, do the particles gain or lose energy.
2. The heat energy supplied to the liquid is absorbed by its molecule & stored as which form of energy.
3. How does the stored energy have an effect on inter-particles space?
4. State why the inter-particles attraction decreases to negligible.
5. At what point will the particles become free and escape as a gas.

Q3) Complete the statement by filling the blanks with the correct word from the brackets.

1. In naphthalene, the inter-particle attraction id ____(high/low)
2. The law of conservation of mass is strictly valid if mass and ____(energy/volume) are considered together.
3. When inter-particle space increases, the inter-particle attractive force _____ (decreases/increases)
4. Kinetic energy of molecules in helium is ____(large/vary large) compared to the kinetic energy molecules in water.
5. Conversation of vapour (or gas) into a liquid is termed _____(liquefaction/vaporization)

Q4) Give the reasons for the following.

1. Particles of matter possess energy called kinetic energy.
2. Solid cannot be compressed, but gases are highly compressible.
3. The Kinetic energy of molecules of gases is very large & solids the least.
4. On heating a sublimable liquid, the molecules break free & escape from the surface of the solid directly into vapour.
5. Particles of matter move more rapidly on the application of heat.

Q5) Complete the blanks with reference to inter-conversion of matter on the basis of kinetic theory with the word ‘increase’, ‘decrease’, ‘gain’, ‘lose’ or ‘overcome’ in each case.

1. During melting od solids, the inter- particles space ____
2. During vaporization, the liquid particles _____ energy.
3. During liquidation, the particles ____ energy.
4. During solidification, the inter-particle space decreases gently _____
5. During sublimation the inter-particle attraction is _____