[Calypso]

Hey guys, this is my first post here so I hope I do this right  

I've been trying to figure out this problem for quite a while and am literally stuck:

A chemist has one mole of an unknown molecule.  The mass of this sample is 111.1 grams.  After doing some tests, the chemist determines that the molecule has 2 chlorines atoms in it and one other atom she cannot identify.  In other words, the molecule's formula is XCL2, where X is unkown.  Based on the mass of the sample, what is atom X?


I know I'm supposed to present some stuff that I've done myself but literally I don't have anything because I don't know where to begin .  If I knew where to start I'm pretty sure I could do the rest of the problem.  If you guys could just help me with even that part it would be amazing.  Thank you so much and please let me know if I broke any rules :/

[kkrizka]

Well, saying that a mole weights 111.1 grams is telling you it's molar mass. In other words one single molecule weight 111.1 amu. Since you know two out of three, you can figure out the mass of the final atom. Hope this helps.