A sample of `CH_(4)` of 0.08g was subjected to combustion at `27^(@)C` in a bomb calorimeter. The temperature of the calorimeter system was found to be raised by `0.25^(@)C`. If heat capacity of calorimeter is `18 kJ//""^(@)C, Delta H` for combustion of `CH_(4)` at `27^(@)C` is

Options

A. `-900` kJ/mole
B. `-905` kJ/mole
C. `-895` kJ/mole
D. `-890` kJ/mole

Answer

B

Explanation

`q = C Delta T = 18 xx 0.25 = 4.5 = q_(V)`
`4.5 kJ rarr (0.08)/(16)` moles
? `rarr` 1 mole `Delta H = Delta E + Delta ng RT`
`CH_(4) + 2o_(2) rarr CO_(2) + 2H_(2)O rArr Delta n_(g) = -2`
`Delta H = -900 - (2 xx 8.314 xx 300)/(1000)= -905` kJ/mole