Question

Nitric oxide, NO, also known as nitrogen monoxide, is one of the primary contributors to air pollution, acid rain, and the depletion of the ozone layer. The reaction of oxygen and nitrogen to form nitric oxide is N2(g) + O2(g) +2NO(9) The heat produced by an automobile engine is sufficient to convert some of the nitrogen and oxygen in the air to nitric oxide. The spontaneity of a reaction can be determined from the sign of, A-G • A reaction is spontaneous when the Gibbs energy change is less than zero. • A reaction is nonspontaneous when the Gibbs energy change is greater than zero. • A reaction is in equilibrium when the Gibbs energy change is equal to zero.

Answer 1

For reaction at non-standard conditions, the Gibbs energy change is related to reaction quotient as follows:

AG = AG° + RT InQ

where

ΔG =  Gibbs energy change at non-standard condition

ΔG0 = Gibbs energy change at standard condition

R - Uniiversal gas constant = 8.314 J / mol K

T - temperature

Q - reaction quotient

At equilibrium we have :

• ΔG = 0
• reaction quotient (Q) = equilibrium constant (K)

Hence we can write the relation between Standard Gibbs energy change (ΔG0) and equilibrium constant (K) as:

AG° = -RT INK

The equation can be re-arranged to write:.

K -(AG"/RT) = e

Given :

ΔG0 = 123 kJ/mol = 123*103 J/mol

T = 2400 K

R = 8.314 J / mol K

K -(123x103/(8.31x2400)) = {

Working this out, we get the value of K as (in 3 significant figures)

K = 0.00210