Use Hess's Law or the summation equation to calculate the ΔHrxn. Round to the nearest tenth!

___NF (g) + ___F2 (g) - -> ___NF2 (g)

½N2 (g) + ½F2 (g) - > NF (g) Hf = 86.6 kJ

½N2 (g) + F2 (g) - > NF2 (g) Hf = 33.8 kJ

The ΔHrxn with the nearest tenth will have value of - 60 K.

Explanation:

NF (g) + ___F2 (g) - -> ___NF2 (g

data given:

½N2 (g) + ½F2 (g) - > NF (g) Hf = 86.6 kJ

½N2 (g) + F2 (g) - > NF2 (g) Hf = 33.8 kJ

Hess's law of heat is summation says that total change in enthalpy during a reaction is same whether the reaction is direct or in various steps.

½N2 (g) + ½F2 (g) - > NF (g) Hf = 86.6 kJ

reversing the equation we get:

NF - > ½N2 (g) + ½F2 (g)

Heat of enthalpy becomes negative so - 86.6 KJ

Now adding both the reactions:

NF - > ½N2 (g) + ½F2 (g)

½N2 (g) + F2 (g) - > NF2 (g) Hf = 33.8 kJ

Removing the common entities from the reaction we get

F2 (g) + NF (g) - -> ½F2 (g) + NF2 (g) Hf

the summation of enthalpy is

-86.6 + 33.8

= 52.8 KJ

The nearest tenth will be - 60 KJ.