# Chemistry 1046

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A metal, M, of atomic mass 91 amu reacts with fluorine to form a salt that can be represented as MFx. In order to determine x and therefore the formula of the salt, a boiling point elevation experiment is performed. A 9.05-g sample of the salt is dissolved in 100.0 g of water and the boiling point of the solution is found to be 374.54 K. Find the formula of the salt. Assume complete dissociation of the salt in solution.

• Chemistry 1046 - ,

assume it is MF3. then

bpe=.52*4*9.05/(.1*(91+3*19))
bpe=18.8/(14.8)=1.2 check that.

Is that equivalent to a new bp of 374.54K?

• Chemistry 1046 - ,

It is not... So where do I go from here?

• Chemistry 1046 - ,

You're right. It isn't MF3.
Do it this way.
delta T = i*Kb*m
If you let MFx ionize into M + xF, then
molar mass is 91+19x and
m = 90.5g/(91+19x)
Substitute delta T, for i substitute x+1, then Kb and m. Solve for x.

• Chemistry 1046 - ,

• Chemistry 1046 - ,

ZrF4 is wrong.

• Chemistry 1046 - ,

This is an OLD question but I'm having trouble on it... *sigh*