One mole of methannol when burnt in oxygen gives out `723 kJ mol^(-1)` heat. If one mole of oxygen is used, what will be the amount of heat evolved ?

Options

A. 723 kJ
B. 964 kJ
C. 482 kJ
D. 241 kJ

Answer

C

Explanation

`underset(2 mol)(2CH_(3)OH) + underset(3 mol)(3O_(2)) rarr 2CO_(2) + 4H_(2)O Delta H = - 723 kJ mol^(-1)`
1 mol of `O_(2) = (2)/(3)` mol of `CH_(3)OH`
:. `(2)/(3)` mol of `CH_(3)OH` on combustion gives
`= (723 xx 2)/(3)` = 482 kJ