Question

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???

Answer 1

deltaH=Hgraphite to CO2+HCO2 to graphite
= -393.5kJ/mol+395.4kJ/mol

Answer 2

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

Answer 3

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