In: Chemistry
Give a statement of Hess's law.
Hess law states that if a reaction takes place in more than one strp, then enthalpy of this reaction is sum of enthalpy of individual steps.
For example:
Suppose the required reaction is:
C + 2H2O —> CO2 + 2 H2
Its enthalpy can be calculated by taking sum of enthalpy of below 2 reactions
C + O2 —> CO2
2 H2O —> 2 H2 + O2