Question

True or False for the following questions......

1) The following reaction is spontaneous at all temperatures.

2NO_2(g) --> N_2(g) + 2O_2(g) ∆H = -123 kJ

2) The following reaction is spontaneous at all temperatures.

3O_2(g) --> 2O_3(g) ∆H = +423 kJ

3) If the following reaction takes place at 300 K, the reaction is spontaneous at 300 K.

N_2(g)  + 3H_2(g) -->   2NH_3(g) ∆H = -90 kJ

∆S for N_2(g) = 192 J/molK; ∆S for H_2(g) = 131 J/molK; ∆S for NH_3(g) = 193 J/molK

4) If the following reaction takes place at 600 K, the reaction is spontaneous at 600 K.

N_2(g)  + 3H_2(g) -->   2NH_3(g)      ∆H = -90 kJ

∆S for N_2(g) = 192 J/molK; ∆S for H_2(g) = 131 J/molK; ∆S for NH_3(g) = 193 J/molK.

5) The following reaction is spontaneous at all temperatures.

2HgO_(s) --> O_2(g) + 2Hg_(l) ∆H = +523 kJ

6) If the standard free-energy change (∆G^o) is negative, then the equilibrium constant (K) is greater than one (i.e., lnK is positive), and thus products are favored over reactants at equilibrium.

7) In any spontaneous process, the total entropy of a system and its surroundings always increases.

8) The entropy of a perfect crystalline substance is zero at the absolute temperature (i.e., at -273 ^oC which is K = 0). Thus, the entropy of any substance at a temperature above 0 K is greater than zero

Answer 1