Answer to Question #208363 in General Chemistry for Czai 19

Question

What is the entropy change of the reaction below at 298 K and 1 atm 

pressure?

 N2(g) + 3H2(g) → 2NH3(g)

S

298 (J/mol•K) 191.5 130.6 192.3 

(a) –198.7 J/K (c) –129.7 J/K

(b) 76.32 J/K (d) 303.2 J/K

2. Evaluate ΔSo for the reaction below at 25°C and 1 atm.

3NO2(g) + H2O(l) → 2HNO3(aq) + NO(g)

So (J/mol•K) 240 69.91 146 210.7

(a) +1.37 x 103 J/K (c) –287.2 J/K

(b) +287.2 J/K (d) +1.37 x 103 J/K

3. The heat of vaporization of methanol, CH3OH, is 35.20 kJ/mol. Its boiling 

point is 64.6°C. What is the change in entropy for the vaporization of 

methanol?

(a) –17.0 J/mol•K (c) 17.0 J/mol•K

(b) 3.25 J/mol•K (d) 104 J/mol•K

Answer 1

1.(a) –198.7 J/K

2.(c) –287.2 J/K

3.(d) 104 J/mol•K