Question

At 25 C the following heats of reaction are known:

2CIf (g)+ O2(g) -> CL2O (g) + f2O
Delta H rxn= 167.4 kj/mol

2CIf3(g) + 2O2 (g)-> Cl2O(g) + 3F2O(g)
Delta H rxn= 341.4

2F2(g) + O2(g) -> 2F2O(g)
Delta H rxn= -43.4kj/mol

at the temperature, use Hess's Law to calculate delta H rxn for the reaction

CIF (g) + F2 (g) -> CIF3 (g)

Hess law confuses me

Answer 1

I have no idea what Clf, f2O and some of the others are.