The standard entropies of N2(g), H2(g) and NH3(g) are 191.5, 130.5, 192.6 JK-1 mol-1. The value of Δ S° during the formation of 1 mole of ammonia is

Question

The standard entropies of N2(g), H2(g) and NH3(g) are 191.5, 130.5, 192.6 JK-1 mol-1. The value of Δ S° during the formation of 1 mole of ammonia is (A) - 98.9 JK-1 mol-1 (B) -9.78 JK-1 mol-1 (C) + 129.4 JK-1 mol-1 (D) Zero

Tardigrade Admin · Accepted Answer

(1/2)N2+(3/2) H2→ NH3 Δ S°=192.6-((1/2)×191.5+(3/2)×130.5) =192.6-(95.75+195.75) =192.6-291.5=-98.9 JK-1 mol-1

Q. The standard entropies of $N_{2} (g), H_{2} (g)$ and $N H_{3} (g)$ are $191.5, 130.5, 192.6 J K^{- 1} m o l^{- 1}$ . The value of $Δ S^{\circ}$ during the formation of $1$ mole of ammonia is

$- 98.9 J K^{- 1} m o l^{- 1}$

$- 9.78 J K^{- 1} m o l^{- 1}$

$+ 129.4 J K^{- 1} m o l^{- 1}$

Zero

$\frac{1}{2} N_{2} + \frac{3}{2} H_{2} \to N H_{3}$
$Δ S^{\circ} = 192.6 - (\frac{1}{2} \times 191.5 + \frac{3}{2} \times 130.5)$
$= 192.6 - (95.75 + 195.75)$
$= 192.6 - 291.5 = - 98.9 J K^{- 1} m o l^{- 1}$

Q. The standard entropies of N2​(g),H2​(g) and NH3​(g) are 191.5,130.5,192.6JK−1mol−1. The value of ΔS∘ during the formation of 1 mole of ammonia is

−98.9JK−1mol−1

−9.78JK−1mol−1

+129.4JK−1mol−1