Consider the two diagrams that follow.
(a) Based on (i), write an equation showing how ?HA is related to ?HB and ?HC. How do both diagram (i) and your equation relate to the fact that enthalpy is a state function?
(b) Based on (ii), write an equation relating ?HZ to the other enthalpy changes in the diagram.
(c) How do these diagrams relate to Hess's law?
