d. how does hesss law use intermediate reactions to calculate the enthalpy of a desired reaction? (2 points)

Brief Explanations:

Hess's law states that the enthalpy change of a reaction is the same whether it occurs in one step or in a series of steps. Intermediate reactions are used to break down the desired reaction into simpler steps. The enthalpy changes of these intermediate reactions are added or subtracted to find the enthalpy change of the desired reaction, as long as the intermediate substances cancel out when the intermediate - reaction equations are combined to give the desired reaction equation.

Answer:

Hess's law uses intermediate reactions by breaking down the desired reaction into simpler steps. The enthalpy changes of the intermediate reactions are combined (added or subtracted) such that the intermediate substances cancel out, and the resulting sum gives the enthalpy change of the desired reaction.