Solution

Note: Given the heat capacity of the apparatus, not the specific heat capacity of the liquid.

Heat capacity = mass Specific heat capacity

E = Heat capacity = 7.45 4.5 = 33.525 kJ

1.5 g of methanol produced 33.525 kJ of heat

1 mole of methanol = 32 g

= 715.2 kJ

The reaction is exothermic. Therefore the heat of combustion = -715.2 kJ