Show all of the enthalpy values involved in the creation of a compound, used to find the lattice enthalpy, or anything else you don’t know
It’s basically Hess’s law (remember it?)
(Not copy, unless you’re desperate for reassurance!)
It’s just a bunch of numbers again, but there’s lots of them. It’s a six-variable problem, one unknown and five known.
(occasionally eight-variable, but you would know seven)