Paper 2 Thermal Physics B Drills

Q1 Ideal gas equation

A cylinder contains $0.240\mathrm{mol}$ of ideal gas at $2.10\times 10^5\mathrm{Pa}$ and $310\mathrm{K}$.

1. Calculate the gas volume. [2]
2. Calculate the number of molecules. [2]
3. Calculate the mean translational kinetic energy per molecule. [2]

Q2 First law

A gas receives $850\mathrm{J}$ by heating and expands, doing $320\mathrm{J}$ of work on the surroundings.

1. Using $\Delta U=Q-W_{by}$, calculate $\Delta U$. [2]
2. State whether the temperature of an ideal gas increases or decreases. [1]
3. Explain why heat supplied is not the same as internal energy change. [2]

Q3 p-V work

A gas expands at constant pressure $1.50\times 10^5\mathrm{Pa}$ from $2.0\times 10^{-3}$ to $5.0\times 10^{-3}{\mathrm{m}}^3$.

1. Calculate work done by the gas. [2]
2. State the sign of work done on the gas. [1]
3. Explain the graph-area interpretation. [2]