The heat produced on combustion of methane is approximately

Question

The heat produced on combustion of methane is approximately (A)  890 kJ , per g  (B)  74.2 kJ , per g  (C)  55.6 kJ , per g  (D)  49.5 kJ , per g

Tardigrade Admin · Accepted Answer

CH4 (g) + 2O2(g) arrow CO2(g) + 2H2O(l) Enthalpy change for a given reaction is equal to = (sum of standard enthalpies of formation of products) - (sum of standard enthalpies of formation of reactants). Given, enthalpy of CO2 = - 393.5 kJ / mol enthalpy of H2O = - 285.8 kJ / mol enthalpy of CH4 = - 74.9 kJ / mol ∴ Enthalpy of combustion of methane = [- 393.5 + 2 × ( - 285.8)] - [- 74.9 + 0] = -965.1 + 74.9 = - 890.2 kj/mol = (890.2/16) kJ/g = -55.6 kJ/g The standard enthalpy of formation is taken as zero, because it is most stable form at 298 K and 1 atm pressure.

Q. The heat produced on combustion of methane is approximately

$890 k J$ , per $g$

$74.2 k J$ , per $g$

$55.6 k J$ , per $g$

$49.5 k J$ , per $g$

Q. The heat produced on combustion of methane is approximately

890kJ , per g

74.2kJ , per g

55.6kJ , per g

49.5kJ , per g

$890 k J$ , per $g$

$74.2 k J$ , per $g$

$55.6 k J$ , per $g$

$49.5 k J$ , per $g$