Question

Calculate the standard enthalpy change of the formation of water (H2O) given the following data:- Standard enthalpy of formation of hydrogen gas (H2) = 0 kJ/mol- Standard enthalpy of formation of oxygen gas (O2) = 0 kJ/mol- Standard enthalpy of formation of water vapor (H2O(g)) = -241.8 kJ/mol

Answer 1

To calculate the standard enthalpy change of the formation of water  H2O , we can use the following equation:Hf H2O  =  Hf products  -  Hf reactants The balanced chemical equation for the formation of water is:H2 g  + 1/2 O2 g   H2O g Now, we can plug in the given standard enthalpies of formation:Hf H2O  = [1  Hf H2O g  ] - [1  Hf H2 g   + 1/2  Hf O2 g  ]Since the standard enthalpy of formation for hydrogen gas  H2  and oxygen gas  O2  are both 0 kJ/mol, the equation simplifies to:Hf H2O  = [1   -241.8 kJ/mol ] - [0 + 0]Hf H2O  = -241.8 kJ/molSo, the standard enthalpy change of the formation of water  H2O  is -241.8 kJ/mol.