What mass of f2 is needed to produce 180 g of pf3 if the reaction has a 78.1% yield?

91.26 g

Explanation:

Given data:

Mass of PF₃ = 180 g

Mass of F₂ required = ?

Solution:

Chemical equation:

P₄ + 6F₂   → 4PF₃

Moles of PF₃:

Number of moles = mass/ molar mass

Number of moles = 180 g/ 88 g/mol

Number of moles = 2.05 mol

Now we will compare the moles of PF₃ with F₂.

                        PF₃            :           F₂

                          4               :           6

                          2.05         :           6/4×2.05 = 3.075

Mass of  F₂:

Mass of F₂ = moles × molar mass

Mass of F₂ = 3.075 mol × 38 g/mol

Mass of F₂ =  116.85 g

If reaction yield is 78.1%:

116.85 /100 ×78.1 = 91.26 g