Answer:
The change in enthalpy in the combustion of 3 moles of methane = -2406 kJ
Explanation:
Step 1: The balanced equation
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) ΔH = -802 kJ
Step 2: Given data
We notice that for 1 mole of methane (CH4), we need 2 moles of O2 to produce : 1 mole of CO2 and 2 moles of H20.
The enthalpy change of combustion, given here as Δ H , tells us how much heat is either absorbed or released by the combustion of one mole of a substance.
In this case: we notice that the combustion of 1 mole of methane gives off (because of the negative number), 802.3 kJ of heat.
Step 3: calculate the enthalpy change for 3 moles
The -802 kj is the enthalpy change for 1 mole
The change in enthalpy for 3 moles = 3* -802 kJ = -2406 kJ
The change in enthalpy in the combustion of 3 moles of methane = -2406 kJ
