How much energy is released during the combustion of 24.0 g of methane, CH4. DeltaH = -90 kJ/mol.
The combustion of methane undergoes according to the following reaction:
CH4 + 2O2 = CO2 + 2H2O
The number of moles of methane equals:
n(methane) = m(methane) / Mr(methane) = 24.0 g / 16.04 g/mol = 1.5 mol
From here, if 1 mol of methane releases 90 kJ, 1.5 mol of methane releases 1.5 mol × 90 kJ/mol = 135 kJ
Answer: 135 kJ