Question

When a 21.1-g sample of ethyl alcohol (molar mass 46.07 g/mol) is burned, how much energy is released as heat?

Answer 1

Answer:

622.87 kJ energy is released as heat.

Explanation:

The heat of combustion of ethyl alcohol = 1360 kJ/mol

When 1 mole ethyl alcohol is burnt it gives 1360 kJ of heat.

Number of moles of ethyl alcohol$=\frac{21.1 g}{46.07 g/mol}=0.4579 mol$

Then 0.4579 mole of ethyl alcohol will give:

$0.4579 mol\times 1360 kJ/mol=622.87 kJ$

622.87 kJ energy is released as heat.