Answer
a. 85 J
b. 85 J
Work Step by Step
a. Calculate the work done by a gas at constant pressure from equation 15–3. No work is done when the volume stays constant.
$$W=P\Delta V=(3atm)(\frac{1.01\times10^5Pa}{1atm})(0.280L)\frac{1\times10^{-3}m^3}{1L}=85J$$
b. Calculate the heat flow from $\Delta U=Q-W$. Note that there is no change in internal energy because there is no change in temperature.
$$\Delta U =0= Q-W=Q-85J $$
Q=W=85J.
