An unidentified gas is determined to be 24.0% carbon and 76% fluorine by mass. What is the empirical formula of this gas

CF₂

Explanation:

Let's assume we have 100 g of the gas. If that were the case we'd have

Now we convert both masses into moles, using their respective molar mass:

We can express those results as C₂F₄.

To determine the empirical formula we reduce those coefficients to the lowest possible integers, leaving us with CF₂.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"