State whether the sign of the entropy change expected for each of the following processes will be

Question:

State whether the sign of the entropy change expected for each of the following processes will be positive or negative, and explain your predictions.
(a) PCl3(l) + Cl2(g) → PCl5(s)
(b) 2HgO(s) → 2Hg(l) + O2(g)
(c) H2(g) → 2H(g)
(d) U(s) + 3F2(g) → UF6(s)