Paper 3 Thermal Physics Route Drills

Q1 Integrated thermal explanation

A sealed rigid container of gas is placed in hot water. The gas temperature rises from $290\mathrm{K}$ to $330\mathrm{K}$.

1. Explain, using thermal equilibrium, why energy is transferred initially. [2]
2. Calculate the pressure ratio. [2]
3. Explain the pressure change microscopically. [3]
4. State whether external boundary work is done by the gas. [1]
5. Use first-law reasoning to state what happens to internal energy. [2]

Q2 Thermal route comparison

A student says: ‘Specific latent heat and first-law work are both just heat, so they can be handled by the same formula.’

1. Identify two errors in the statement. [2]
2. Explain when $E=mL$ is appropriate. [2]
3. Explain why heat and work are not state properties. [3]