Hello, Jaden,
We need to balance the equation. I come up with:
2BrF3 = Br2 + 3F2
We want 29.2 g of flourine gas, F2. Using the molar mass of F2, 38 g/mole, we can calculate this to be (29.2 g/38 g/mole), or 0.768 moles of F2.
The balanced equation tells us we need 2 moles of BF3 to make 3 moles of F2, a (2 BF3/3 F2) molar ratio.
To obtain 0.768 moles of F2, we therefore need:
(0.768 moles F2)*(2 BF3/3 F2) = 0.512 moles BrF3
Convert this to grams by multiplying by the molar mass of BrF3, 136.9 g/mole. This says we need 70.1 grams of BrF3 to make 29.2 grams of F2.
Bob