The reaction through which carbon changes from graphite to diamond form is represented by the equation

C(graphite) ---> C(diamond) delta H: ?

Using the reactions below, determine the amount of heat absorbed in the change of one mole of graphite to one mole of diamond

C(graphite) + O2 ---> CO2(g) delta H is -393.5 kJ/mol

C(diamond) + O2(g) ---> CO2(g) Delta H is -395.4 kJ/mol

Do i do the same thing where i add the two equations of delta H???

deltaH=Hgraphite to CO2+HCO2 to graphite

= -393.5kJ/mol+395.4kJ/mol

So i would change the sign of the second equation and add them?

Yes, you have reversed the reaction to get diamond. sign of delta H reverses.

To determine the amount of heat absorbed in the change from graphite to diamond, you can use the concept of Hess's Law, which states that the enthalpy change of a reaction is independent of the pathway taken. You can use the given reactions and their enthalpy changes to find the enthalpy change for the transformation of graphite to diamond.

In this case, since the two reactions involve the formation of CO2, you need to manipulate the given reactions to have the same products and reactants as the desired reaction: C(graphite) ---> C(diamond)

First, reverse the second equation so that the carbon is in its original form (graphite):

CO2(g) ---> C(diamond) + O2(g) (reverse the sign of ΔH: 395.4 kJ/mol)

Next, add the two reactions together in a way that cancels out the CO2 on both sides:

C(graphite) + O2 ---> CO2(g) (ΔH: -393.5 kJ/mol)
CO2(g) ---> C(diamond) + O2(g) (ΔH: 395.4 kJ/mol)

When you add these two equations together, you can see that the reactant O2 and the product O2 cancel out:

C(graphite) + O2 + CO2(g) ---> CO2(g) + C(diamond)

Simplifying the equation, you get the desired reaction:

C(graphite) ---> C(diamond)

Now, you can add the enthalpy changes of the two equations to find the enthalpy change of the desired reaction:

ΔH(graphite to diamond) = ΔH(reaction 1) + ΔH(reaction 2)
= -393.5 kJ/mol + (-395.4 kJ/mol)

Calculate the sum:

ΔH(graphite to diamond) = -393.5 kJ/mol - 395.4 kJ/mol
= -788.9 kJ/mol

Therefore, the amount of heat absorbed in the change of one mole of graphite to one mole of diamond is -788.9 kJ/mol.