Answer to Question #109058 in General Chemistry for kim

Question

9) Use data from Appendix IIB in the textbook to calculate the equilibrium constants at 25∘C for each of the following reactions.
part a) 2NO(g)+O2(g)⇌2NO2(g)
part b) N2(g)+O2(g)⇌2NO(g)

10) Consider the following reaction:
CO(g)+2H2(g)⇌CH3OH(g)
Kp=2.26×104 at 25 ∘C. Calculate ΔGrxn for the reaction at 25 ∘C under each of the following conditions.
part a) standard conditions
part b) at equilibrium
part c) PCH3OH= 1.5 atm ;
PCO=PH2= 1.2×10−2 atm

Answer 1

(10)We know $∆G_{rxn}=-RTln(K)$

(a)at standard conditions

$∆G_{rxn}=-8.314×298×ln(2.26×10^4)$

$∆G_{rxn}=-8.314×298×1.8345=4545.13232$

(b)at equilibrium

$∆G=0$

(c)$P_{CH_3OH}=1.5 atm;P_{CO}=0.012atm;P_{H_2}=0.012atm$

$K_p=\frac{[CH_3OH]}{[CO][H_2]^2}=\frac{1.5}{0.012^3}=8.68×10^{5}$

$∆G_{rxn}=-8.314×298×ln(8.68×10^5)$

$∆G_{rxn}=-8.314×298×5.94$

$∆G_{rxn}=14713.1102$

(9)(a)$2NO+O_2->2NO_2$

0.002 0.001 0.05

At equilibrium no of moles of each compound.

$K_c=\frac{[NO_2]^2}{[NO]^2[O_2]}$

$K_c=\frac{[0.05]^2}{[0.002]^2[0.001]}=6.9×10^5/mol$

(b)$N_2(g)+O_2(g)->2NO(g)$

0.036 0.0089 3.6

At equilibrium no of moles of each compound.

$K_c=\frac{[NO]^2}{[N_2][O_2]}$

$K_c=\frac{[3.6]^2}{[0.036][0.0089]}=4.1×10^4$