Alright dude, Hess' law isn't as complicated as most people think
Take this example
look for the change in enthalpy of A+B-> AB
A + B -> C enthalpy=10 kJ
C -> AB enthalpy=10 kJ
now if you add everything together you come up with
A + B + C --> AB + C enthalpy= 10kJ + 10 kJ= 20kJ
But notice how C is one the left and on the right of that-- so if it's on the left and on the right of the equation, you could just cancel it out
so you get A+B--> AB
tadaaa!! You found the equation you were looking for
and you know that it's enthalpy is= 10kJ + 10kJ= 20kJ
Hope that helps ya fam!
