2.2 Thermal Properties of Matter

Question 1

What is thermal expansion?

Answer 1

When heated, molecules have more energy and so vibrate faster. The collide with each other more and push each other apart.

Question 2

Explain thermal expansion in solids

Answer 2

Question 3

Explain thermal expansion in liquids

Answer 3

Question 4

Explain thermal expansion in gases

Answer 4

Question 5

Give uses and consequences of thermal expansion

Answer 5

Uses: thermometers, temperature-activated switches
Consequences: Buckling of railways, bridges and roads if they get too hot

Question 6

What is internal energy?

Answer 6

The total energy stored inside a system due to the motion (kinetic energy - temperature) and positions (potential energy - potential collisions) of the molecules

Question 7

What can an increase in average kinetic energy do to a material?

Answer 7

• Increase its temperature
• Induce a change of state (solid –> liquid –> gas)

Question 8

What is specific heat capacity?

Answer 8

The amount of energy required to raise the temperature of 1kg of the substance by 1°C

Question 9

Give the formula for specific heat capacity

Answer 9

ΔE = change in thermal energy
m = mass
c = specific heat capacity
Δθ = change in temperature