Consider the unbalanced reaction CO + H2O > CH4 + O2. All reactants in the gas phase. Calculate H per mole of H2O reacted. (The > is an arrow)
To calculate the enthalpy change per mole of H2O reacted, we need to use the standard enthalpies of formation for the reactants and products involved in the reaction. The standard enthalpy of formation (∆Hf) is the enthalpy change when one mole of a compound is formed from its elements in their standard states at a specified temperature.
Here's how you can calculate H per mole of H2O reacted:
Step 1: Write the balanced chemical equation for the reaction:
CO + H2O → CH4 + O2
Step 2: Determine the standard enthalpies of formation for each compound involved in the reaction. These values are typically given in tables or can be found online. The standard enthalpies of formation (∆Hf) at 298 K are:
∆Hf(CO) = -110.5 kJ/mol
∆Hf(H2O) = -285.8 kJ/mol
∆Hf(CH4) = -74.8 kJ/mol
∆Hf(O2) = 0 kJ/mol
Step 3: Calculate the difference in enthalpy (∆H) between the products and the reactants:
∆H = (∑∆Hf(products)) - (∑∆Hf(reactants))
In this case:
∆H = (∆Hf(CH4) + ∆Hf(O2)) - (∆Hf(CO) + ∆Hf(H2O))
∆H = (-74.8 kJ/mol + 0 kJ/mol) - (-110.5 kJ/mol + -285.8 kJ/mol)
∆H = -74.8 kJ/mol + 396.3 kJ/mol
∆H = 321.5 kJ/mol
So, the enthalpy change per mole of H2O reacted (∆H per mole of H2O) is 321.5 kJ/mol.