Upon decomposition, one sample of magnesium fluoride produced 1.65 kg{\rm kg} of magnesium and 2.58 kg{\rm kg} of fluorine. A second sample produced 1.50 kg{\rm kg} of magnesium. How much fluorine (in grams) did the second sample produce?

Answer 1

MgF2 ==> Mg + F2
......1.65kg..2.58 kg
So you must have started with 1.65 + 2.58 = ? kg MgF2.

MgF2 ==> Mg + F2
.......1.50kg..?
I would use ratio/proportion on this.
(1.65/1.50) = (2.58/x)
Solve for x.

Answer 2

3.4 * 10^3