I am given the number of moles of an ideal monotomic gas. I am also given a chart with a graph of temperature plotted as a function of entropy. One of the questions is: find the heat that was transferred to the gas. How do I find that? I thought about saying: dS = dQ/T <=> dQ = T dS then I found the slope of the graph with respect to S and found the y-intercept. So now I had T in terms of S and I said: dQ = (mS + b) dS taking the integral of both sides I found Q and was able to easily integrate from initial entropy to final entropy. But I got the answer wrong. I don't want to do it all over again, unless I am sure this is the right approach. Is there an easier way? This is problem #8 in Chapter 21 of Halliday/resnick/walker 6th edition.