Question

Calculate the enthalpy change for the reaction: 2H₂(g) + O₂(g) → 2H₂O(g) The enthalpy of formation of H₂O is -242 kJ/mol, and the enthalpy of formation of O₂ is 0 kJ/mol.

Answer 1

To calculate the enthalpy change for the reaction, we can use the following formula:H_reaction =  H_f products  -  H_f reactants where H_reaction is the enthalpy change for the reaction, H_f products  is the sum of the enthalpies of formation of the products, and H_f reactants  is the sum of the enthalpies of formation of the reactants.For this reaction, we have:Reactants: 2H g  and O g Products: 2HO g H_f HO  = -242 kJ/molH_f O  = 0 kJ/molH_f H  = 0 kJ/mol  since it is an element in its standard state Now, we can plug these values into the formula:H_reaction = [2   -242 kJ/mol ] - [2  0 kJ/mol + 0 kJ/mol]H_reaction =  -484 kJ  -  0 kJ H_reaction = -484 kJThe enthalpy change for the reaction is -484 kJ.