Question

K,Cro, + Pb(NO), - PbCro, * 2KNO,
If 25.0 grams of K,Cro, reacts to produce 20 grams of PbCroy, what is the
percent yield of PbCro?

Answer 1

Answer:

Percent yield = 47.6 %

Explanation:

Given data:

Mass of K₂CrO₄ react = 25.0 g

Mass of PbCrO₄ produced = 20 g

Percent yield of PbCrO₄ = ?

Solution:

Chemical equation:

K₂CrO₄ + Pb(NO₃)₂   →    PbCrO₄ + 2KNO₃

Number of moles of K₂CrO₄:

Number of moles = mass/molar mass

Number of moles = 25.0 g/ 194.19 g/mol

Number of moles = 0.13 mol

Now we will compare the moles of K₂CrO₄ and PbCrO₄ .

                       K₂CrO₄       :            PbCrO₄

                            1               :               1

                           0.13           :             0.13

Mass of PbCrO₄: Theoretical yield

Mass = number of moles × molar mass

Mass = 0.13 mol × 323.2 g/mol

Mass = 42.0 g

Percent yield:

Percent yield = ( actual yield / theoretical yield )× 100

Percent yield = (20 g/ 42.0 g ) × 100

Percent yield = 47.6 %