WorksheetsLimited Reactant
Total questions: 20
Worksheet time: 42mins
Name
Class
Date
1.
The limiting reactant
a)
slows the reaction down
b)
is used up first
c)
is the reactant that is left over
d)
controls the speed of the reaction
2.
Use the equation 2 Al + 3 Cl2 ---> 2 AlCl3. If 2 moles of aluminum and 2 moles of chlorine are reacted, identify the limiting reactant.
a)
AlCl3
b)
Cl2
c)
Al
3.
When does a chemical reaction stop?
a)
When the lab is finished
b)
When the excess reactant is used up
c)
When the limiting reactant is used up
d)
Chemical reactions never stop
4.
When 12 moles of O2 reacts with 1.1 mole of C10H8 what is the limiting reactant? C10H8 + 12 O2 --> 10 CO2 + 4 H2O
a)
Oxygen
b)
C10H8
c)
Water
d)
Carbon Dioxide
5.
Theoretical yield = 73g
Actual yield = 62g
Calculate the percent yield.
Actual yield = 62g
Calculate the percent yield.
a)
1.16%
b)
116%
c)
85%
d)
76%
6.
P4 + 3O2 --> P4O6
What is the limiting reactant is 12 moles of P4 react with 15 moles of O2?
What is the limiting reactant is 12 moles of P4 react with 15 moles of O2?
a)
P4
b)
O2
c)
P4O6
d)
none of the above
7.
4NH3 + 5O2 --> 4NO + 6H2O
How many grams of NO are formed if 6.30g of ammonia react with 1.80g of oxygen?
How many grams of NO are formed if 6.30g of ammonia react with 1.80g of oxygen?
a)
0.37g
b)
0.045g
c)
1.35g
d)
11.1g
8.
P4 + 6Cl2 --> 4PCl3
The reaction of 75.0g P4 with excess chlorine gas produces 110g PCl3 in lab. Find the theoretical yield and calculate percent yield for the reaction.
The reaction of 75.0g P4 with excess chlorine gas produces 110g PCl3 in lab. Find the theoretical yield and calculate percent yield for the reaction.
a)
78%
b)
64%
c)
27%
d)
33%
9.
What is a limiting reactant?
a)
the reactant that determines how much product can be made
b)
the reactant that is in excess
c)
the product that you can make the most of
d)
the amount of reactants that react with each other
10.
The following chemical equation represents a reaction that we will do in the lab next quarter:
Mg (s) + 2 HCl (aq) → MgCl2 (aq) + H2 (aq)
How many grams of excess reagent will be left over when 6.00 g of HCl reacts with 5.00 g of Mg?
(hint: determine the limiting reagent first )
a)
4 g
b)
1 g
c)
2 g
d)
3 g
11.
When reacting Na with Cl2, we calculated that the theoretical yield should be 12.5 grams. Our actual yield was 13.0 grams. What is the percent yield?
a)
100%
b)
104%
c)
96%
d)
1.04
12.
In a lab, a scientist calculate he should produce 12.3 grams of product in his experiment. When he is finished collecting his product it weighs 10.1 grams. What is his percent yield?
a)
82%
b)
0.82%
c)
10.1 %
d)
100%
13.
Which of the following is true of the law of conservation of mass?
a)
The same number and type of each atom will always be present before and after a chemical reaction takes place.
b)
Some of the atoms present before the reaction will always be lost during a chemical reaction.
c)
Some of the atoms will always be changed into a different type of atom by a chemical reaction.
d)
During a chemical reaction, atoms will always be combined into much larger molecules.
14.
If a chemist calculates the maximum amount of product that could be obtained in a chemical reaction, he or she is calculating the
a)
theoretical yield
b)
mole ratio
c)
actual yield
d)
percentage yield
15.
The excess reactant is not completely used up during the reaction.
a)
True
b)
False
16.
In a balanced equation, the ratio between the numbers of moles of any two substances.
a)
percent yield
b)
actual yield
c)
mole ratio
d)
excess reactant
17.
A reactant that remains after a chemical reaction stops.
a)
limiting reactant
b)
percent yield
c)
excess reactant
d)
mole ratio
18.
The ratio of actual yield to theoretical yield expressed as a percent.
a)
percent yield
b)
theoretical yield
c)
mole ratio
d)
actual yield
19.
4.3 grams of sodium reacts with 2.6 grams of oxygen to produce 5.9 grams of sodium oxide. Using Na as your limiting reactant, what is your theoretical yield?
a)
5.8 g
b)
5.796 g
c)
10.07 g
d)
10. g
20.
If 2 moles of aluminum and 2 moles of chlorine are reacted in a synthesis reaction, identify the limiting reactant. [HINT: You will need to write and balance your own chemical reaction first.]
a)
AlCl3
b)
Cl2
c)
Al
100 %
