Question

For the reaction

2A ( g ) + B ( g ) → 2D ( g )

Δ U θ = –10.5 kJ and Δ S θ = –44.1 JK –1 .

Calculate Δ G θ for the reaction, and predict whether the reaction may occur spontaneously.

Answer 1

Dear Student,For the given reaction,
2 A(g) + B(g) → 2D(g)
Δng = 2 – (3)
= –1 mole
Substituting the value of ΔUθ in the expression of ΔH:
ΔHθ = ΔUθ + ΔngRT
= (–10.5 kJ) – (–1) (8.314 × 10–3 kJ K–1 mol–1) (298 K)
= –10.5 kJ – 2.48 kJ
ΔHθ = –12.98 kJ
Substituting the values of ΔHθ and ΔSθ in the expression of ΔGθ:
ΔGθ = ΔHθ – TΔSθ
= –12.98 kJ – (298 K) (–44.1 J K–1)
= –12.98 kJ + 13.14 kJ
ΔGθ = + 0.16 kJ
Since ΔGθ for the reaction is positive, the reaction will not occur spontaneously.Best Of Luck...!!!!

Answer 2

Dear Student,For the given reaction,

2 A(g) + B(g) + 2D(g)

Ang = 2 - (3)

= -1 mole

Substituting the value of AUO in the expression of AH:

ΔΗθ-Δυθ + Δ gRT

= (-10.5 kJ) – (-1) (8.314 × 10–3 kJ K

1 mol-1) (298 K)

= -10.5 kJ - 2.48 kJ

AHO = -12.98 kJ

Substituting the values of AHO and

ASe in the expression of AGe:

AGO = AHO – TASO

= -12.98 kJ – (298 K) (-44.1 J K-1)

= -12.98 kJ + 13.14 kJ

AGO = + 0.16 kJ

Since AGO for the reaction is

positive, the reaction will not occur

spontaneously.Best Of Luck...!!

BG2000 · Helping Hand