Sulphur `(2.56g)` is burend in a constant volume calorimeter with excess `O_(2)(g)` . The temperature increases from `21.25^(@)` to `26.72^(@)C` , The bomb has a heat capacity of `923JK^(-1)` . Calorimeter energy contains `815g` of water. Thus, change in internal energy per mole of `SO_(2)` formed for the reaction is
`S_(8)(s)+8O_(2)(g)8SO_(2)(g)`
(specific heat of water is `4.184JK^(-1)g^(-1))` .

Options

A. `-296.27KJ`
B. `+296.27KJ`
C. `-2370.13KJ`
D. `+2370.13KJ`

Answer

B

Explanation

Moles of `S_(8)=(2.56)/(256)=0.01`
Moles of `SO_(2)` formed `=0.08`
Rise in temperature `=(273+26.72)K-(273+21.25)K`
`=5.47K`
Total change in internal energy
(as system is at constant volume)
`=-(923JK^(-1)xx5.47K+815gxx4.184JK^(-1)g^(-1)xx5.47K)`
`=-23701.29J=-23.70129KJ`
Thus, change in internal energy per mole of `SO_(2)` formed
`=-(23.7012g)/(0.08)=-296.3KJ,ol^(-1)`