Upon decomposition, one sample of magnesium fluoride produced 1.64 kg of magnesium and 2.57 kg of fluorine. A second sample produced 1.38 kg of magnesium.

Question

How much fluorine (in grams) did the second sample produce?

Answer 1

I don't know what procedure you are to use. The following is not a mole ratio type solution.
2.57 kg x (1.38/1.64) = ?? kg F2.

Answer 2

2.162560976