Problem: The fuel in high-efficiency natural gas vehicles consists primarily of methane CH4.How much heat is produced in burning 6 mol of CH4 under standard conditions if reactants and products are brought to 298 K and H2 O(l) is formed?

FREE Expert Solution

We’re being asked to determine the amount of heat produced by burning 6 mol of CH4 under standard conditions


The heat produced by the combustion reaction is equivalent to the standard enthalpy change of formation (ΔH˚f) for CH4. Recall that ΔH˚rxn can be calculated from the enthalpy of formation (ΔH˚f) of the reactants and products involved


H°rxn = H°f, products - H°f, reactants  


We will do the following steps:

Step 1: Write and balance the combustion reaction

Step 2: Calculate ΔH˚rxn for the combustion of per mole of methane

Step 3: Calculate ΔH˚rxn for the combustion of 6 mole of methane


Step 1: Write and balance the combustion reaction 


Recall that for compounds composed of C and H, the combustion reaction looks like this:


CxH+ O2 (excess) x CO2 + y H2O


The combustion reaction produces CO2 and H2O.


The chemical equation for the combustion of CH4 reaction is:

CH4(g) + O2(g) → CO2(g) + H2O(l)


This equation is not yet balanced. To balance it, we have to make sure that the number of elements on both sides is equal.


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Problem Details

The fuel in high-efficiency natural gas vehicles consists primarily of methane CH4.

How much heat is produced in burning 6 mol of CH4 under standard conditions if reactants and products are brought to 298 K and H2 O(l) is formed?