Kinetic Theory and States of Matter

Question 1

In which state of matter do particles move fastest?

Answer 1

Gas

Question 2

During which two changes of state does a liquid become a gas?

Answer 2

Boiling and evaporation

Question 3

In which state of matter is density generally highest? How is this explained by the particle model?

Answer 3

Solid

In the particle model, particles are arranged closest together in the solid state.

Question 4

In which state of matter are particles free to move?

Answer 4

Gas

Question 5

Describe the differences between the arrangement of particles in solids and liquids.

Answer 5

In solids particles have fixed, regular arrangements, whereas in liquids particles can move past each other and their arrangements are irregular.

Question 6

Explain why heating a system can make the particles in the system move faster.

Answer 6

Heating a system can transfer energy to the kinetic energy stores of the particles in the system. The more energy in the kinetic energy store of a particle, the faster it moves.

Question 7

Explain why mass is conserved when a substance changes state.

Answer 7

In a change of state the number of particles stays the same, so the mass is conserved.

Question 8

A change of state is a physical change. What is meant by this?

Answer 8

The change of state doesn’t produce a new substance; instead the substance changes form and can recover its original properties if the change of state is reversed.