Consider these changes. (a) Hg(l)-Hg(g) (b) 3O2(g)-2O3(g) (c) CuSo4*5H2O(s)-CuSO4(s)+5H2O(g) (d) H2(g)+F2(g)-2HF(g) At constant pressure, in which of the reactions is work done by the system on the surroundings? By the surroundings on the system? In which of them is no work done?

Question

Consider these changes. (a) Hg(l)->Hg(g) (b) 3O2(g)->2O3(g) (c) CuSo4*5H2O(s)->CuSO4(s)+5H2O(g) (d) H2(g)+F2(g)->2HF(g) At constant pressure, in which of the reactions is work done by the system on the surroundings? By the surroundings on the system? In which of them is no work done?

DrBob222 · Accepted Answer

a and c more gas on product side so system expands and P*delta V is done on surrounding.
b fewer moles on right than left so system contracts and p*delta V is done by surroundings.
d no change in volume so no work done.