Consider the following unbalanced reaction.

Question

P4(s) + F2(g)---> PF3(g)
How many grams of F2 are needed to produce 114 g of PF3 if the reaction has a 80.3% yield?

I've worked it every way I can think, and the online grader says I am wrong. Someone plz lend me a hand.

Answer 1

well, there are about 50 ways to do it.

114 g of PF3 has how many grams of F in it? 114*atomicmassF/molmassPF3= 114(31/(50)=? you can work all that more accurately.

so how many grams of F2 is this? answer: 1/2 of the above.
With 80.3 percent yield? you need aboveF2 mass* (1/.803) grams F2

Answer 2

The conventional way to do this is with mole ratios, but it has to be balanced first.