Heat of combustion Δ H° for C ( s ), H 2( g ) and CH 4( g ) are -94,-68 and -213 Kcal / mol then Δ H ° for C ( s )+2 H 2( g ) → CH 4( g ) is:-

Question

Heat of combustion Δ H° for C ( s ), H 2( g ) and CH 4( g ) are -94,-68 and -213 Kcal / mol then Δ H ° for C ( s )+2 H 2( g ) → CH 4( g ) is:- (A) - 17 Kcal (B) - 111 Kcal (C) - 170 Kcal (D) - 85 Kcal

Tardigrade Admin · Accepted Answer

For reaction , C (s) + 2H2 (g) → CH4(g), Δ H° = ? Δ H° = - [(H° of combustion of C + 2× Δ H of combustion of H2)] C + O2 → CC2; Δ H = - 94 kcal 2H2 +O2 → 2H2O; Δ H = - 68 × 2 kcal? CH4 +2O2 → CO2+ 2H2O; Δ = - 213 kcal = - [(-213) - (-94+2 × - 68)] Kcal/mol = - [-213+230] = - 17 kcal/mol

Q. Heat of combustion ΔH∘ for C(s),H2​(g) and CH4​(g) are -94,-68 and −213Kcal/mol then ΔH∘ for C(s)+2H2​(g)→CH4​(g) is:-

- 17 Kcal

- 111 Kcal

- 170 Kcal

- 85 Kcal

Q. Heat of combustion $Δ H^{\circ}$ for $C (s), H_{2} (g)$ and $C H_{4} (g)$ are -94,-68 and $- 213 Kc a l / m o l$ then $Δ H^{\circ}$ for $C (s) + 2 H_{2} (g) \to C H_{4} (g)$ is:-