Using Appendix C, compare the standard entropies at 25°C for the following pairs of substances:
(a) CuO(s) and Cu2O(s)
(b) 1 mol N2O4(g) and 2 mol NO2(g)
(c) SiO2(s) and CO2(g)
(d) CO(g) and CO2(g). For each pair, explain the difference in the entropy values.