A compound whose empirical formula is XF3 consists of 65% F by mass. What is the atomic mass of X?

Video transcript

Hey everyone. So here we have to calculate the atomic mass of the unknown element A. In the formula A. B. R two cl two Given that it is composed of 61.75% roaming by mass but from a mass percent. Given we can find a total mass of the compound used in bro means atomic mass. Recall that mass percent is the mass of the element divided by the mass of the compound Times 100 Healthy plug in advice we get 61.75 equals 79 .90. Times two because we have to grow mean divided by X Times 100%. We're gonna get 61.75 times X People 259 .90. Times 100 Defeated by both sides by 61.75%. We're going to get X 0.79 and this is grams per mole. So now we're gonna set up the equation algebraic lee to find the atomic mass of a gonna have eight plus two Master Bro me which is 79 .904 transfer mode. Last two Times the molar mass of chlorine which is .453 transfer remote. We're gonna get 258 0.79 grams promote for the total mass of the compound They're going to eight Plus 230 . France from all. Eagle. 258 0.79 transform all. Now because we tracked both sides by 230 .714 grants promote. We're gonna get eight. It was 28.08 grams per mole. Thanks for watching my video and I hope it was helpful.