Question

Calculate the standard Gibbs free energy change for the following chemical reaction at 25°C:2H2(g) + O2(g) → 2H2O(l)The standard Gibbs free energy of formation at 25°C for H2O(l) is -237.2 kJ/mol, H2(g) is 0 kJ/mol, and O2(g) is 0 kJ/mol.

Answer 1

To calculate the standard Gibbs free energy change  G  for the reaction, we can use the following equation:G =  [Gf products ] -  [Gf reactants ]where Gf is the standard Gibbs free energy of formation for each substance.For the given reaction:2H2 g  + O2 g   2H2O l The standard Gibbs free energy of formation for each substance at 25C is:H2O l : -237.2 kJ/molH2 g : 0 kJ/molO2 g : 0 kJ/molNow, we can plug these values into the equation:G = [2   -237.2 kJ/mol ] - [2   0 kJ/mol  + 1   0 kJ/mol ]G = [-474.4 kJ/mol] - [0 kJ/mol]G = -474.4 kJ/molSo, the standard Gibbs free energy change for the reaction at 25C is -474.4 kJ/mol.