A reaction takes place in two steps. In the first step 12.5 cal of energy are released. In the second step, 68.2 J of energy are released and the volume of the gas expands by 14.4 L at a pressure of 12.5 atm. Given that 1 L·atm = 101.3 J, what is the overall energy change?

Question

wolfe8 · Answer

I think you can just add from the two steps watching the units, but since the gas expanded, you will subtract the energy used to expand the gas. I think you get the energy spent for expansion by multiplying 101.3 J with the volume expanded and the pressure.