Question

1. Calculate the ΔG°_rxn using the following information.

2 HNO₃(aq) + NO(g) → 3 NO₂(g) + H₂O(l) ΔG°_rxn = ?
ΔG°_f (kJ/mol) -110.9 87.6 51.3 -237.1

2.Determine the equilibrium constant for the following reaction at 549 K.

CH₂O(g) + 2 H₂(g) → CH₄(g) + H₂O(g) ΔH° = -94.9 kJ; ΔS°= -224.2 J/K

3.Calculate ΔG_rxn at 298 K under the conditions shown below for the following reaction.

CaCO₃(s) → CaO(s) + CO₂(g) ΔG° = +131.1 kJ

P(CO₂) = 0.033 atm

Answer 1

1)

Given:

Gof(HNO3(aq)) = -110.0 KJ/mol

Gof(NO(g)) = 87.6 KJ/mol

Gof(NO2(g)) = 51.3 KJ/mol

Gof(H2O(l)) = -237.1 KJ/mol

Balanced chemical equation is:

2 HNO3(aq) + NO(g) ---> 3 NO2(g) + H2O(l)

ΔGo rxn = 3*Gof(NO2(g)) + 1*Gof(H2O(l)) - 2*Gof( HNO3(aq)) - 1*Gof(NO(g))

ΔGo rxn = 3*(51.3) + 1*(-237.1) - 2*(-110.0) - 1*(87.6)

ΔGo rxn = 49.2 KJ/mol

Answer: 49.2 KJ/mol

2)

1st find ΔGo

ΔHo = -94.9KJ/mol

ΔSo = -224.2J/mol.k

= -0.2242 KJ/mol.K

T = 549 K

use:

ΔGo = ΔHo - T*ΔSo

ΔGo = -94.9 - 549.0 * -0.2242

ΔGo = 28.2 KJ/mol

Now we have:

T = 549 K

G = 28.2 KJ/mol

G = 28200 J/mol

use:

ΔG = -R*T*ln Kc

28200 = - 8.314*549.0* ln(Kc)

ln Kc = -6.178

Kc = 2.07*10^-3

Answer: 2.07*10^-3

I am allowed to answer only 1 question at a time