Question

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

Answer 1

`q^(combustion)_(acetylene)=-1100.2kJ/mol`

Step-by-step 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:

`Q_(acetylene)=-Q_(calorimeter)`

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:

`n_(acetylene)q^(combustion)_(acetylene)=-C_(calorimeter)\Delta T_(calorimeter)`

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

`q^(combustion)_(acetylene)=(-C_(calorimeter)\Delta T_(calorimeter))/(n_(acetylene)) =(-31.5kJ/\°C*16.9\°C)/(12.6g*(1mol)/(26.04g) ) \\\\q^(combustion)_(acetylene)=-1100.2kJ/mol`

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