Question

Calculate the standard enthalpy of formation of carbon dioxide given the following information: - Standard enthalpy of formation of graphite = 0 kJ/mol- Standard enthalpy of formation of oxygen gas = 0 kJ/mol- Enthalpy of combustion of graphite = -393.5 kJ/mol- Enthalpy of combustion of carbon monoxide = -283.0 kJ/mol- Enthalpy of combustion of hydrogen gas = -285.8 kJ/mol

Answer 1

To calculate the standard enthalpy of formation of carbon dioxide  CO2 , we can use the given information about the enthalpy of combustion of graphite and the standard enthalpy of formation of the reactants.The combustion reaction of graphite can be written as:C graphite  + O2 g   CO2 g The standard enthalpy change for this reaction  H  is equal to the enthalpy of combustion of graphite:H = -393.5 kJ/molSince the standard enthalpy of formation of graphite and oxygen gas are both 0 kJ/mol, we can write the standard enthalpy change for the reaction as:H = Hf CO2  - [Hf C  + Hf O2 ]Where Hf CO2  is the standard enthalpy of formation of CO2, Hf C  is the standard enthalpy of formation of graphite, and Hf O2  is the standard enthalpy of formation of oxygen gas.Substituting the given values, we have:-393.5 kJ/mol = Hf CO2  - [0 kJ/mol + 0 kJ/mol]Solving for Hf CO2 :Hf CO2  = -393.5 kJ/molTherefore, the standard enthalpy of formation of carbon dioxide is -393.5 kJ/mol.