posted by Anonymous .
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?
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.