Question

How much heat is produced by combustion of 125 g of methanol under standard state conditions?

Answer 1

Answer:

Energy released = 2832.79 kJ

Explanation:

The standard enthalpy of the combustion of methanol, $\Delta\ H^0=-726.1\ kJ/mol$

It means that :

1 mole of methanol on combustion releases 726.1 kJ of energy

Molar mass of methanol = 32.04 g/mol

Thus, mass of 1 mole of methanol is 32.04 g

So,

32.04 g of methanol on combustion releases 726.1 kJ of energy

1 g of methanol on combustion releases 726.1/32.04 kJ of energy

125 g of methanol on combustion releases (726.1/32.04)*125 kJ of energy

Energy released = 2832.79 kJ

Answer 2

Standard enthalpy of combustion is the enthalpy change for one mole of a substance that burns or combines with the oxygen under the standard state conditions that is 1 bar pressure and  temperature.