Chemistry question on enthalpy HELP

The enthalpy change for this reaction is, -803 kJ

Explanation:

The balanced chemical reaction is,

The expression for enthalpy change is,

where,

n = number of moles  

Now put all the given values in this expression, we get

Therefore, the enthalpy change for combustion of methane is, -803 kJ

answer; /// the amount of material dissolved in a measure of liquid(concentration) the above statement is (true); /// good luck