Chapter 19, Problem 47P

(III) In the process of taking a gas from state a to state c along the curved path shown in Fig. 19–32, 85 J of heat leaves the system and 55 J of work is done on the system. (a) Determine the change in internal energy. E_{int, a} – E_{int, c} (b) When the gas is taken along the path cda, the work done by the gas is W = 38 J. How much heat Q is added to the gas in the process cda? (c) If P_a = 2.2P_d, how much work is done by the gas in the process abc? (d) What is Q for path abc? (e) If E_{int, a} – E_{int, b} = 15 J, what is Q for the process be? Here is a summary of what is given:

$\begin{array}{c}{Q}_{\text{a}\to \text{c}}=-85\text{J}\\ W_{\text{a}\to \text{c}}=-55\text{J}\\ W_{\text{cda}}=38\text{J}\\ E_{\text{int,a}}-E_{\text{int,b}}=15\text{J}\\ P_{\text{a}}=2.2P_{\text{d}}.\end{array}$