The heat of combustion of carbon to `CO_(2)`is`-395.5kJ//mol`.The heat released upon the formation of`35.2g` of`CO_(2)`from carbon and oxygen gas is

Options

A. `+315kJ`
B. `-31.5kJ`
C. `-315kJ`
D. `+31.5kJ`

Answer

C

Explanation

`C+O_(2)toCO_(2),DeltaH=-393.5`kJ/mol
It means heat of formation of 1 mole (44 g) of `CO_(2)`
`=-393.5` kJ/mol
`:.` Heat of formation of 1 g of `CO_(2)=(-393.5)/44` KJ/mol
Heat of formation of 35.2 of `CO_(2)=(-393.5)/44xx35.2`
`=-314.8kJ=-315kJ`