Answer to Question #343633 in General Chemistry for sham

Question

Calculate the free energy change for the reaction shown below at 25oC. 2NO + O2 → NO3

Answer 1

$\Delta G=\Delta H-T\Delta S$

$2NO+O_2\rightarrow 2NO_2$

[2ΔH_f(NO₂ (g))] - [2ΔH_f(NO (g)) + 1ΔHf(O₂ (g))]

[2(33.18)] - [2(90.25) + 1(0)] = -114.14 kJ

[2ΔS_f(NO₂(g))] - [2ΔS_f(NO (g)) + 1ΔS_f(O₂ (g))]

[2(239.95)] - [2(210.65) + 1(205.03)] = -146.43 J/K

T=25+273=298K

[2ΔG_f(NO₂ (g))] - [2ΔG_f(NO (g)) + 1ΔG_f(O₂ (g))]

[2(51.3)] - [2(86.57) + 1(0)] = -70.54 kJ

-70.54 kJ (spontaneous)