Both are solved the same way. I'll do the first one.
Take a 100 g sample which gives you
47.7 g Cr
52.3 g F
Convert to mols. mol = g/atomic mass
mols Cr = 47.7/52 = about 0.92
mols F = 52.3/19 = about 2.75
Now find the ratio of one element to the other with the smallest number being 1.0. The easy way to do that is divide both numbers by the smaller one.
0.92/0.92 = 1.00
2.75/0.92 = 2.99 which rounds to a whole number of 3.0
So the formula is Cr1.00F3.00 but you don't need the 1.00 and the formula we usually write is CrF3.
Post your work if you want me to check your work on part b.
Determine the empirical formula for the following compounds with these compositions (by mass):
a) Cr 47.7% F 52.3%
b) Na 42.1% P 18.9% O 39.0%
2 answers
Na3PO4
2 answers