[Smilesrck]

So ill get to the point i got no clue what to do.
2 XBr₃+ 3Cl₂  2XCl₃ + 3 Br₂
A 2.5178 g sample of XBr₃ completly rects with excess chlorine to produce 1.6357 g of XCl₃. What is the aromic mass of X and what element is it? Answers are 140.9g/mol & Pr
This is my 94th problem of my problem set (for ch.3 already at like 300+ >_>) and im ready to bang my head against a wall in frustration.

[Borek]

You have to show your attempts at solving the problem to receive help, this is a forum policy.

Hint: number of moles of X doesn't change.

[Smilesrck]

You have to show your attempts at solving the problem to receive help, this is a forum policy.

Hint: number of moles of X doesn't change.

Okay so tried to do was to find moles and have grams of bromine be times x so it was 239.712x grams then did this with Cl (106.359x) to find moles. Using orginal grams. However i got two different moles answers so that was the wrong way to do it. Next i tried the grams over the grams for moles and equaled it to each other. Thinking back not a good idea :/ blame 2am. My next idea was that x has to be equal to each other but i couldnt figure out a way to do it :c

[Borek]

Assume molar mass of X to be x (that will be your unknown). Use it to express molar masses of XCl₃ and XBr₃. Can you find what the ratio of these molar masses is?