Question

this reaction
Hoog H6 to 2"
occurs in​

Answer 1

The difference between heats of reaction at constant pressure and constant volume for the reaction,

2C

6

H

6

(l)+15O

2

(g)→12CO

2

(g)+6H

2

O(l) at 25

o

C in kJ is:

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ANSWER

The heat of reaction is basically ΔH at constant pressure and is ΔU at constant volume.

Since, for any reaction the relation between this heats is given by equation,

ΔH = ΔU + (Δn

g

)RT

where, Δn

g

= change in number of gaseous moles in any reaction.

Since, in the above reaction the only gaseous species are CO

2

and O

2

, so,

Δn

g

=12−15=−3.

Hence, using ΔH - ΔU = (Δn

g

)RT

ΔH - ΔU =(−3)RT=(−3)×8.314×298.15J (T in Kelvin)

=> ΔH - ΔU=7430J=7.43KJ

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