8.
In a reaction, my theoretical yield of phosphorus trichloride is 23.10 g. If I actually
produce 13.50 g of phosphorus trichloride, what is my percent yield?
Percent Yield =
actual
13.50 g PCl3
x 100 =
x 100 = 58.44 % yield
theoretical
23.10 g PCl3
Balance the reaction below. Use it to answer problem 9.
__2__ KOH + ____ CuBr2 → __2__ KBr + ____ Cu(OH)2
9.
In the above reaction, 41.0 g KOH reacts with 74.0 g CuBr2:
a. Determine the theoretical yield of KBr.
1 mol KOH
2 mol KBr
119.00 g KBr
x
x
= 87.0 g KBr
56.11 g KOH
2 mol KOH
1 mol KBr
41.0 g KOH x
1 mol CuBr2
2 mol KBr
119.00 g KBr
x
x
= 78.9 g KBr ←theoretical
223.35 g CuBr2 1 mol CuBr2
1 mol KBr
74.0 g CuBr2 x
b. Identify the limiting and excess reactants.
Limiting – CuBr2
Excess – KOH
c. Calculate the amount of excess reactant remaining.
74.0 g CuBr2 x
1 mol CuBr2
2 mol KOH
56.11 g KOH
x
x
= 37.2 g KOH
223.35 g CuBr2 1 mol CuBr2
1 mol KOH
Remaining = starting – used = 41.0 g KOH – 37.2 g KOH = 3.8 g KOH
d. Calculate the percent yield if your actual yield was 61.2 g of KBr.
Percent Yield =
actual
61.2 g KBr
x 100 =
x 100 = 77.57 % yield
theoretical
78.9 g KBr