Question

A sample of 0.30 moles of a metal M reacts completely with excess fluorine to form 18.69 grams of MF2.

How many moles of F are in the sample of MF2 that forms?

M + F2 ---> MF2


How many grams of M are in this sample of MF2 ?

Answer 1

M + F2 ==> MF2
0.3mole M means 0.3 mole F2. How many grams is that? moles F2 x molar mass F2 = g fluorine.
18.69 = g MF2
- grams fluorine
----------------
7.+ grams must be M.
Then moles = g/molar mass and solve for molar mass.

Answer 2

thank you :)