Question
How is Hess’s law helpful in calculating the enthalpy of formation of carbon monoxide?
Solution
Enthalpy of formation of carbon monoxide cannot be determined experimentally since the combustion of carbon will never stop at CO(g) stage. A small amount of CO2(g) will be always formed. The enthalpy of formation of carbon monoxide can be calculated by Hess’s law.
The thermochemical equation.
Experimentally it has been found that
Subtracting equation (ii) from (i), we have,
The thermochemical equation.
Experimentally it has been found that
Subtracting equation (ii) from (i), we have,
