Question

The actual heat of formation of MgO is -601.8 kJ/mol. Convert this to kcal/mol and calculate your % error. And list two possible sources of procedural error to account for this percentage.

Answer 1

-601 kJ/mol x (1 kcal/4.184 kJ) = ? kcal/mol.

%error = (actual value-experimental value/actual value)*100 = ??
You're on your own for the rest of it; we don't know how the experiment was conducted.