Question

Calculate the enthalpy change for the reaction: 2H2(g) + O2(g) → 2H2O(l)given that the enthalpy change of formation for water (H2O) is -285.8 kJ/mol.

Answer 1

To calculate the enthalpy change for the reaction, we can use the following equation:H_reaction =  H_f products  -  H_f reactants In this case, the reactants are H2 g  and O2 g , and the product is H2O l . The enthalpy change of formation for H2 g  and O2 g  is 0 kJ/mol, as they are in their standard states. The enthalpy change of formation for H2O l  is given as -285.8 kJ/mol.The balanced equation is:2H2 g  + O2 g   2H2O l Now, we can plug in the values into the equation:H_reaction = [2   -285.8 kJ/mol ] - [2  0 kJ/mol + 0 kJ/mol]H_reaction =  -571.6 kJ/mol  - 0H_reaction = -571.6 kJ/molThe enthalpy change for the reaction is -571.6 kJ/mol.