posted by annemarie on .
The enthalpy of combustion of benzoic acid,C6H5COOH, which is often used to calibrate calorimeters, is
-3227kJ/mol. When 1.236g of benzoic acid was burned in a calorimeter, the tempurature increased by 2.345K. What is the specific heat of the calorimeter?
First, how many moles is 1.236g of benzoic acid? That ought to give you a clue as to how much heat was liberated.
and you can solve for the specific heat.
Now a note of error on this method: Enthalpy of combustion is taken as if at constant temperature, so in this method one ignores the heat content of the products when they are not at the original temperature. The products are CO2, H2O vapor. This is valid here because the mass of products will be trivial to the mass of the calorimeter.
Specific Heat of the calorimeter will be calculated here in kJ/Celcius.