Name ______KEY____________________________________ Date _________ Period ______
Limiting Reactants
Balance the reaction below. Use it to answer question 1.
____Cu + __2__AgNO3 → ____Cu(NO3)2 + __2__Ag
1.
65.39
169.88
187.57
107.87
In the above reaction, 16.7 grams of copper react with 27.8 g of silver nitrate.
a. Determine the theoretical yield of copper (II) nitrate.
16.7 g Cu x
27.8 g AgNO3 x
1 mol Cu
1 mol Cu(NO3)2 187.57 g Cu(NO3)2
x
x
= 49.3 g Cu(NO3)2
63.55 g Cu
1 mol Cu
1 mol Cu(NO3)2
1 mol AgNO3
1 mol Cu(NO3)2 187.57 g Cu(NO3)2
x
x
= 15.3 g Cu(NO3)2 ←theoretical
169.88 g AgNO3
2 mol AgNO3
1 mol Cu(NO3)2
b. Identify the limiting and excess reactants.
Limiting – AgNO3
Excess – Cu
c. Calculate the amount of excess reactant remaining.
27.8 g AgNO3 x
1 mol AgNO3
1 mol Cu
63.55 g Cu
x
x
= 5.20 g Cu
169.88 g AgNO3 2 mol AgNO3
1 mol Cu
Remaining = starting – used = 16.7 g Cu – 5.20 g Cu = 11.5 g Cu
Balance the reaction below. Use it to answer problem 2.
____ CaO + ____ H2O → ____ Ca(OH)2
2.
56.08
18.02
74.10
In the above reaction, 4.44 g of calcium oxide reacts with 7.77 g of water.
a. Determine the theoretical yield of calcium hydroxide.
4.44 g CaO x
1 mol CaO
1 mol Ca(OH)2 74.10 g Ca(OH)2
x
x
= 5.87 g Ca(OH)2 ←theoretical
56.08 g CaO
1 mol CaO
1 mol Ca(OH)2
7.77 g H2O x
1 mol H2O
1 mol Ca(OH)2 74.10 g Ca(OH)2
x
x
= 32.0 g Ca(OH)2
18.02 g H2O
1 mol H2O
1 mol Ca(OH)2
b. Identify the limiting and excess reactants.
Limiting – CaO
Excess – H2O
c. How much of the excess reactant remains after the reaction is finished?
4.44 g CaO x
1 mol CaO
1 mol H2O 18.02 g H2O
x
x
= 1.43 g H2O
56.08 g CaO 1 mol CaO
1 mol H2O
Remaining = starting – used = 7.77 g H2O – 1.43 g H2O = 6.34 g H2O