Question

The enthalpy of combustion of naphthalene (MW = 128.17 g/mol) is -5139.6 kJ/mol. How much energy is produced by burning 0.8210 g of naphthalene?

Answer 1

The energy produced : -32.89 kJ

Further explanation

Delta H reaction (ΔH) is the amount of heat / heat change between the system and its environment

(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)

The enthalpy of combustion of naphthalene (MW = 128.17 g/mol) is -5139.6 kJ/mol.

For 0.8210 g of naphthalene :

mol =

`\tt mol=(mass)/(MW)\\\\mol=(0.8210)/(128.17)=0.0064`

The energy produced :

`\tt Q=\Delta H* n(mol)\\\\Q=-5139.6* 0.0064=-32.89~kJ`