How much heat is produced when 29.6 g of methanol react with 45.9 g of oxygen?

1 Answer
Nov 19, 2016

You need to supply the enthalpy of combustion of methanol.


Methanol combusts according to the reaction:

#H_3COH + 3/2O_2(g) rarr CO_2(g) + 2H_2O+Delta#

This reaction will be exothermic. Just how exothermic it will be is subject to measurement, which you have not quoted.

#"Moles of methanol"=(29.6*g)/(32.04*g*mol^-1)=0.924*mol#.

#"Moles of dioxygen"=(45.9*g)/(32.0*g*mol^-1)=1.41*mol#.

Given the molar quantities, there is sufficient dioxygen for complete combustion. However, we still need the molar enthalpy of combustion.