Question

PART A.

Acetylene, C2H2, can be converted to ethane, C2H6, by a process known as hydrogenation. The reaction is

C2H2(g)+2H2(g)⇌C2H6(g)

All pressures equal to 1 atm and the common reference temperature 298 K, What is Kp?

Substance	ΔG∘f (kJ/mol)
C2H2(g)	209.2
H2(g)	0
C2H6(g)	−32.89

PART B.

At 25 ∘C the reaction from Part A has a composition as shown in the table below.

Substance	Pressure (atm)
C2H2(g)	4.95
H2(g)	5.65
C2H6(g)	1.25×10−2

What is the free energy change, ΔG, in kilojoules for the reaction under these conditions?

Answer 1

Here asked free energy change

∆G = ∆G° + RTlnK

∆G° = -242.09 kJ / mol ( from part A)

∆G = -242.09 kJ / mol -23.4 kJ/mol

∆G = -265.49 kJ