Problem: When a 0.240-g sample of benzoic acid is combusted in a bomb calorimeter, the temperature rises 1.643 oC . When a 0.270-g sample of caffeine, C8H10O2N4, is burned, the temperature rises 1.523 oC . Using the value 26.38 kJ/g for the heat of combustion of benzoic acid, calculate the heat of combustion per mole of caffeine at constant volume.

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Calculate the heat capacity of the calorimeter:

Q = mCTC=(0.240  g)(26.38 kJg )( 1.643°C )Q= 3.85 kJ°C

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Problem Details

When a 0.240-g sample of benzoic acid is combusted in a bomb calorimeter, the temperature rises 1.643 oC . When a 0.270-g sample of caffeine, C8H10O2N4, is burned, the temperature rises 1.523 oC . Using the value 26.38 kJ/g for the heat of combustion of benzoic acid, calculate the heat of combustion per mole of caffeine at constant volume.

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