Calculate the difference between heat of combustion of carbon monoxide gas at constant pressure and at constant volume at 27°C? (R = 2 cal `K^(-1) mol^(-1)`)

Options

A. 54 cal
B. - 600 cal
C. - 300 cal
D. 27 cal

Answer

C

Explanation

Given
`T=27^(@)C=300K`
`R=2calK^(-1)mol^(-1)`
Reaction for combustion of carbon monoxide is given as:
`CO(g)+1/2O_(2)(g)toCO_(2)(g)`
`thereforeDeltan_(g)=1-15=-1/2`
Now, the difference between heat of combustion of carbon monoxide gas at constant pressure and at constant volume is given by
`DeltaH-DeltaU=Deltan_(g)RT`
`thereforeDeltaH-DeltaU=-1/2xx2xx300=-300 cal`