Question

Using the standard enthalpies of formation, what is the standard enthalpy of reaction? CO + H20 -> CO2+H2

Answer 1

The standard enthalpy of the reaction is going to be equal to the sum of the standard enthalpy of the products minus the sum of the standard enthalpy of the reactants.
You need the values of the standard entalpy of all the components of the reaction. Look in the attached table for the values of delta H of the following compounds
CO
H2O
CO2
H2

then add the delta H of CO2 + delta H of H2 and subtract the values of the delta H of CO and the delta H of H2O (there are two H2O gas and liquid choose the appropriate one)