Chemistry AS level energetics question

The combustion of methane is an exothermic reaction:
CH4 + 2O2  CO2 + 2H2O ΔH = -890 kJmol-1
Calculate the heat energy released when 100 g of methane is burned
The answer is 5560 kJ but no idea how to get this value

Reply 1

Kvothe the Arcane

Original post by imaan2121

Enthalpy change is

\dfrac{\text{mc}\Delta \text{t}}{\text{mol}}

And this is expressed in

KJmol^{-1}

. Now you know that

mol=\dfrac{mass}{Mr}

so (using dimensional analysis) it follows that in order to get the heat energy released in Kj you must multiply by the number of moles which is the same as multiplying by the mass of and dividing by the Mr of methane.