Question

There are two different compounds of sulfur and fluorine.
In SF6, the mass of fluorine per gram of sulfur is 3.55 g F/g S.
In the other compound, SFX, the mass of fluorine per gram of sulfur is 1.18 g F/g S.
What is the value of X for the second compound?
Express your answer as an integer.

Answer 1

Atomic mass of F: 19.0 g/mol

Atomic mass of S: 32.1 g/mol

1.18 g F = [1.18 g / 19.0 g / mol] = 0.062  mol F

1 g S =  1 g/ 32.1 g/mol = 0.031  mol S

Divide by 0.031

0.062 mol F / 0.031 = 2  mol F

0.031 mol S / 0.031 = 1 mol S

SF2 Then X = 2

Verification:
F2 = 2*19.0 g = 38 g F
S = 32.1 g

36 gF / 32.1 g S = 1.18 g F / g S