Physics 9702 · AS & A Level · The first law of thermodynamics
The first law of thermodynamics — practice question
A fixed mass of an ideal gas has a volume of $210\,\text{cm}^3$ when the pressure is $3.0 \times 10^5\,\text{Pa}$ and the temperature is $270\,\text{K}$. The gas volume is then lowered at constant pressure to $140\,\text{cm}^3$, as shown in Fig. 2.1. The final temperature of the gas is $T$.
(a(i))[3]
Determine the amount of gas present.
(a(ii))[2]
Determine the gas's final temperature $T$.
(a(iii))[2]
Determine the external work done on the gas.
(b)[3]
For this change in the gas's volume and temperature, the thermal energy transferred is $53\,\text{J}$. Determine $\Delta U$, the change in internal energy of the gas.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Application of ideal gas equation $pV=nRT$” …