Question

Calculate the standard enthalpy of formation for carbon dioxide (CO2) given the following information: ΔHf° of CO = -26.4 kJ/mol, ΔHf° of O2 = 0 kJ/mol, and ΔH°rxn for the combustion of carbon to form CO2 is -393.5 kJ/mol.

Answer 1

To calculate the standard enthalpy of formation  Hf  for carbon dioxide  CO2 , we can use the following equation:Hf CO2  = Hrxn - Hf CO  - Hf O2 We are given the following information:Hf CO  = -26.4 kJ/molHf O2  = 0 kJ/mol  since O2 is an element in its standard state Hrxn  combustion of carbon to form CO2  = -393.5 kJ/molNow, we can plug these values into the equation:Hf CO2  = -393.5 kJ/mol -  -26.4 kJ/mol  - 0 kJ/molHf CO2  = -393.5 kJ/mol + 26.4 kJ/molHf CO2  = -367.1 kJ/molTherefore, the standard enthalpy of formation for carbon dioxide  CO2  is -367.1 kJ/mol.