The value of enthalpy change `(DeltaH)` for the reaction
`C_(2)H_(5)OH (l)+3O_(2) (g) rarr 2CO_(2) (g) +3H_(2)O (l)`
at `27^(@)C` is `-1366.5 kJ mol^(-1)`.
The value of internal energy change for the above reactio at this temperature will be

Options

A. `-1371.5 kJ `
B. `-1369.0 kJ `
C. `- 1364.0 kJ`
D. `-1361.5kJ `

Answer

c

Explanation

`C_(2)H_(5)OH(l) + 3O_(2)(g) rarr2CO_(2)(g) + 3H_(2)O(l)`,` Deltan_(g)= 2-3= -1`
`DeltaU = DeltaH -Deltan_(g)RT`
`= - 1366.5 kJ mol^(-1) - ( -1) xx 8.314 xx 10^(-3) kJ K^(-1) mol^(-1) xx 300K`
`= - 1366.5 + 0.8314 xx 3 kJ mol^(-1)`
`=- 1366.5 +2.4942 = - 1364kJ mol^(-1)`