Home
Class 12
CHEMISTRY
At 300K , the standard enthalpies of for...

At `300K` , the standard enthalpies of formation of `C_(6)H_(5)COOH_((s),CO_(2(g))` and `H_(2)O_((l))` are `-408,-393` and `-286kJ mol^(-1)` respectively. Calculate the heat of combustion of benzoic acid at
`(i)` constant pressure,
`(ii)` constant volume. `(R=8.31J mol^(-1)K^(-1))`

A

`-2629 KJ`

B

`-2751 KJ`

C

`-2808 KJ`

D

`-3201 KJ`

Text Solution

Verified by Experts

The correct Answer is:
D
`C_(6)H_(5)COOH_((5))+(15)/(2)O_(2(g))to 7CO_(2(g))+3H_(2)O_((R ))`
`Delta H = [7xx(-393)+3xx(-286]-[(-408)+0]`
`=-3201 kJ`
Promotional Banner

Similar Questions

Explore conceptually related problems

At 300 K, the standard enthalpies of formation of C_(6)H_(5)COOH(s),CO_(2)(g) and H_(2)O(l) are -408,-393 and -286kJ mol^(-1) respectively. Calculate the heat of combustion of benzoic acid at (i) constant pressure and (ii) constant volume. (R=8.31J" "mol^(-1)K^(-1))

The standard enthalpy of formation of C_(2)H_(4)(l) , CO_(2)(g) and H_(2)O(l) are 52 , 394 and -286 kJ mol^(-1) respectively. Then the amount of heat evolved by burning 7g of C_(2)H_(4)(g) is

The molar enthalpies of combustion of C_(2)H_(2)(g), C("graphite") and H_(2)(g) are -1300,-394 , and -286 kJ mol^(-1) , respectively. The standard enthalpy of formation of C_(2)H_(2)(g) is

The enthalpy of formation for C_(2)H_(4)(g),CO_(2)(g) and H_(2)O(l) at 25^(@)C and 1 atm. Pressure are 52, -394 and -286 KJ mol^(-1) respectively. The entahlpy of combustion of C_(2)H_(4) will be :-

The enthalpy of formation for C_(2)H_(4)(g) , CO_(2)(g) and H_(2)O(l) at 25^(@)C and 1 atm. Pressure be 52 , -394 and -286 kJ mol^(-1) respectively. The enthalpy of combustion of C_(2)H_(4)(g) will be