Answer
(a) $-114.4\,JK^{-1}mol^{-1}$
(b) $-332.3\,JK^{-1}mol^{-1}$
(c) $133.9\,JK^{-1}mol^{-1}$
(d) $-173\,JK^{-1}mol^{-1}$
Work Step by Step
Recall: $\Delta S^{\circ}_{rxn}=\Sigma n_{p}S^{\circ}(products)-\Sigma n_{r}S^{\circ}(reactants)$
(a) $\Delta S^{\circ}_{rxn}=[4S^{\circ}(NO_{2},g)+6S^{\circ}(H_{2}O,g)]-[4S^{\circ}(NH_{3},g)+7S^{\circ}(O_{2},g)]$
$=[4(240.1\,JK^{-1}mol^{-1})+6(188.8\,JK^{-1}mol^{-1})]-[4(192.8\,JK^{-1}mol^{-1})+7(205.2\,JK^{-1}mol^{-1})]$
$=-114.4\,JK^{-1}mol^{-1}$
(b) $\Delta S^{\circ}_{rxn}=[S^{\circ}(CH_{3}OH,l)]-[S^{\circ}(CO,g)+2S^{\circ}(H_{2},g)]$
$=(126.8\,JK^{-1}mol^{-1})-[(197.7\,JK^{-1}mol^{-1})+2(130.7\,JK^{-1}mol^{-1})]$
$=-332.3\,JK^{-1}mol^{-1}$
(c) $\Delta S^{\circ}_{rxn}=[S^{\circ}(CO,g)+S^{\circ}(H_{2},g)]-[S^{\circ}(C,graphite)+S^{\circ}(H_{2}O,g)]$
$=[(197.7\,JK^{-1}mol^{-1})+(130.7\,JK^{-1}mol^{-1})]-[(5.7\,JK^{-1}mol^{-1})+(188.8\,JK^{-1}mol^{-1})]$
$=133.9\,JK^{-1}mol^{-1}$
(d) $\Delta S^{\circ}_{rxn}=[2S^{\circ}(CO_{2},g)]-[2S^{\circ}(CO,g)+S^{\circ}(O_{2},g)]$
$=[2(213.8\,JK^{-1}mol^{-1})]-[2(197.7\,JK^{-1}mol^{-1})+(205.2\,JK^{-1}mol^{-1})]$
$=-173\,JK^{-1}mol^{-1}$
