A 0.2254 g sample of naphthalene (C8H10, 128.16 g/mol) was burned in a bomb calorimeter with a heat capacity of 2.18 kJ/K, and the temperature increased by 4.16°C. What is the molar enthalpy of combustion for this compound?

Question

A 0.2254 g sample of naphthalene (C8H10, 128.16 g/mol) was burned in a bomb calorimeter with a heat capacity of 2.18 kJ/K, and the temperature increased by 4.16°C.  What is the molar enthalpy of combustion for this compound?

anonymous · Answer

To figure this out, you need to find out how much energy was transferred to the calorimeter. Multiply the heat capacity by the temperature change and you'll have the amount of energy. Next, divide the masss (0.2254g) by the formual weight to find out how many moles are in 0.2254g of naphthalene. If you divide the energy by the number of moles then you will have the answer (in kJ per mole). If you want to do the math I can check back with you.

anonymous · Answer

Thank you so much, I got 5.16 x 10^3! is that correct? (:

anonymous · Answer

I just worked it out and I get the same as you do - I think you have the correct answer, in kJ/mole. The thing about physics and chemistry is to always check you have the correct units. Any more problems and I'll try and help you out, Best wishes