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.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.