Heat of combustion of methane is -800 kJ. How much heat is required for combustion of `4 xx 10^(-4)` kg of methane ?

Options

A. -15 kJ
B. `-18 kJ`
C. -20 kJ
D. -22 kJ

Answer

C

Explanation

`CH4(g) +202(g) (R ) CO2(g) +H2O(l)`
i.e. 16 g of CH4 evolves -800 kJ of energy.
Therefore, `0.4xx10^(-4) kg (0.4g)` will evolve -20 kJ energy.