(i) C(s)+O2( g)→CO2(g); ΔHi=−94kcal/mole (ii) 2H2(g)+O2(g)→2H2O(l); ΔHii=−68×2kcal/mole (iii) CH4(g)+2O2(g)→CO2(g)+ 2H2O(l);ΔHiii=−213kcal/mol (iv) C(s)+2H2(g)→CH4( g); ΔHIV= ? By applying Hess's law we can compute ΔHiv. ∴ΔHiv=ΔHi+ΔHii−ΔHiii=(−94−68×2+213)kcal=−17kcal
Heat of combustion Δ H° for C(s), H_2(g) and CH_4(g) are -94,-68 and -213 kcal mol^-1, then, Δ H° for C(s)+2 H_2(g) → CH_4(g) is:
NEET UG 2002 — Chemistry Physical Chemistry
Heat of combustion ΔH∘ for C(s),H2(g) and CH4(g) are −94,−68 and −213kcal mol−1, then, ΔH∘ for C(s)+2H2(g)→ CH4(g) is:
Held on 30 Apr 2002 · Verified 9 Jul 2026.
Options
- A
−17kcal
- B
−111kcal
- C
−170kcal
- D
−85kcal
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