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?

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 %

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !