The energy produced by burning : -32.92 kJ
Further explanation
Delta H reaction (ΔH) is the amount of heat change between the system and its environment
(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)
The enthalpy and heat(energy) can be formulated :
[tex]\tt \Delta H=\dfrac{Q}{n}\rightarrow n=mol[/tex]
The enthalpy of combustion of naphthalene (MW = 128.17 g/mol) is -5139.6 kJ/mol.
The energy released for 0.8210 g of naphthalene :
[tex]\tt Q=\Delta H\times n\\\\Q=-5139.6~kJ/mol\times \dfrac{0.8210~g}{128.17~g/mol}~\\\\Q=-32.92~kJ[/tex]
