Answer to Question #60114 in Physical Chemistry for joseph orobiyi

Question

12 All of the following statements concerning entropy are true EXCEPT
entropy is zero for elements under standard conditions.
entropy is a state function.
a positive change in entropy denotes a change toward greater disorder.
entropy values are greater than or equal to zero.



13 All of the following processes lead to an increase in entropy EXCEPT
increasing the temperature of a gas.
freezing a liquid.
evaporating a liquid.
forming mixtures from pure substances.



14 Which reaction is likely to have a negative change in entropy?
$2 NH_3(s) \rightarrow N_2(g) + 3 H_2(g)$
$CaO(s) + CO_2(g) \rightarrow CaCO_3(s)$
$NaCl(s) \rightarrow Na^+(aq) + Cl^-(aq)$
$N_2O_4(g) \rightarrow 2 NO_2(g)$



15 Calculate the standard entropy change for the following reaction, $2
Ag_2O(s) \rightarrow 4 Ag(s) + O_2(g)$ given $S^º[Ag_2O]$ = 121.3
J/K·mol, $S^º[Ag(s)]$ = 42.6 J/K·mol, and $S^º[O_2(g)]$ = 205.1 J/K·mol.
-205.1 J/K
-126.4 J/K
+126.4 J/K
+132.9 J/K