Question

Given:

CH4 + 2O2 → CO2 + 2H2O, ΔH = -890 kJ/mol


How much energy is released when 59.7 grams of methane (CH4) reacts with oxygen?


The combustion of 59.7 grams of methane releases ___ kilojoules of energy


(I've seen two different answers both with goof reviews but I don't know which one is correct. This is for Edmentum btw)

Answer 1

The combustion will release -3,321 KJ/mol of energy

Step-by-step explanation:

What we need to do here is to first calculate the number of moles of methane burnt.

Mathematically, the number of moles of methane burnt = mass of methane/molar mass of methane

Molar mass of methane = 16g /mol

Thus the

number of moles will be ;

59.7/16 = 3.73 moles

Now, 1 mole of methane produces -890 KJ/mol if energy

Then the energy produced by by 3.73 moles of methane would be 3.73 * 890 = -3,320.8125

which is approximately -3,321 KJ/mol

Kindly note that the amount of heat is negative because it is an exothermic reaction