Question

Consider the reaction at `300K`
`C_(6)H_(6)(l)+(15)/(2)O_(2)(g)rarr 6CO_(2)(g)+3H_(2)O(l),DeltaH=-3271`kJ
What is `DeltaU` for the combustion of `1.5` mole of benzene at `27^(@)C` ?
A. `-3267.25kJ`
B. `-4900.88kJ`
C. `-4906.5kJ`
D. `-3274.75kJ`

Answer 1

Correct Answer - 2
For 1 mole of combustion of benzene
`Deltan=-1.5`
`DeltaH^(@)=DeltaU+Deltan_(9)RT`
`rArr-3271=DeltaU-(1.5xx8.314xx300)/(1000)`
`rArr" "DeltaU=-3267.25xx1.5=-4900.88kJ`