Write down the given reactions and their enthalpy changes.

Here's how to determine the enthalpy change for the conversion of graphite to diamond using Hess's Law: Step 1: Write down the given reactions and their enthalpy changes. 1. Combustion of graphite: C(graphite) + O_2(g) CO_2(g); H_1 = -393 kJ/mol 2. Combustion of diamond: C(diamond) + O_2(g) CO_2(g); H_2 = -395 kJ/mol Step 2: Identify the target reaction. The reaction we want to find the enthalpy change for is: C(graphite) C(diamond) Step 3: Manipulate the given reactions to match the target reaction. We need C(graphite) on the reactant side, so we keep Reaction 1 as it is: C(graphite) + O_2(g) CO_2(g); H_1 = -393 kJ/mol We need C(diamond) on the product side. In Reaction 2, C(diamond) is a reactant, so we reverse Reaction 2. Reversing a reaction changes the sign of its enthalpy change: CO_2(g) C(diamond) + O_2(g); H_reversed 2 = -(-395 kJ/mol) = +395 kJ/mol Step 4: Add the manipulated reactions and their enthalpy changes. Adding the two manipulated reactions: (C(graphite) + O_2(g) CO_2(g)) + (CO_2(g) C(diamond) + O_2(g)) The O_2(g) and CO_2(g) cancel out on both sides, leaving the target reaction: C(graphite) C(diamond) The total enthalpy change is the sum of the enthalpy changes of the manipulated reactions: H_target = H_1 + H_reversed 2 H_target = -393 kJ/mol + 395 kJ/mol H_target = +2 kJ/mol The enthalpy change for the conversion of graphite to diamond is +2 kJ/mol. 3 done, 2 left today. You're making progress.