For the reaction 3H 2(g) + N 2(g) 2NH 3(g), K c = 9.0 at 350°C. What is the value of ΔG at this temperature when 1.0 mol NH 3, 5.0 mol N 2, and 5.0 mol H 2 are mixed in a 2.5 L reactor?

ΔG = - 31.7kJ/mol

Explanation:

It is possible to find ΔG of a reaction at certain temperature knowing Kc following the equation:

ΔG = ΔG° + RT ln Q

ΔG° = -RT lnKc

ΔG = -RT lnKc + RT ln Q (1)

Where R is gas constant (8.314J/molK), T absolute temperature (350°C + 273.15 = 623.15K) and Q reaction quotient

For the reaction,

3H₂(g) + N₂(g) ⇄ 2NH₃(g)

Q = [NH₃]² / [H₂]³[N₂]

Where the concentrations of each chemical are:

[NH₃] = 1.0mol / 2.5L = 0.4M

[H₂] = 5.0mol / 2.5L = 2M

[N₂] = 2.5mol / 2.5L = 1M}

Q = [0.4M]² / [2M]³[1M]

Q = 0.02

And replacing in (1):

ΔG = -RT lnKc + RT ln Q

ΔG = -8.314J/molK*623.15K ln 9 + 8.314J/molK*623.15K ln 0.02

ΔG = - 31651J/mol

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.