Answer:
W = -25 J
Explanation:
For a cyclic process, the variation of internal energy (ΔU) must be 0. It means that ΔU from step 1 must be equal to ΔU from step 2. For the first law of the thermodynamics, the energy must be conserved, so:
ΔU = Q - W, from each step. Q is the heat and W the work
When the heat is gained by the system, the process is endothermic, so Q >0, when the system loses heat, the process is exothermic, and Q<0. When the system is expanding W>0, and when it is compressing, W<0.
From step 1:
ΔU = 42 - 14
ΔU = 28 J
From step 2:
28 = -53 - W
W = -53 + 28
W = -25 J
