The heat capacity of a bomb calorimeter was determined to be 31.5 kJ/oC. A 12.6 g sample of acetylene, C2H2, produced a temperature increase of 16.9oC when it was combusted in the calorimeter. What is the energy of combustion of acetylene in kJ/mol

Explanation:

Hello.

In this case, for this calorimetry problem, since the acetylene is burned into the calorimeter causing a temperature increase, we can infer that the combustion of acetylene releases heat which is absorbed by the calorimeter, therefore, the following equation can be written:

Which can be written in terms of the energy of combustion and moles of the acetylene and the heat capacity and temperature change of the calorimeter:

Thus, since the molar mass of acetylene is 26.04 g/mol, the resulting energy of combustion of the acetylene turns out:

Best regards!

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"