WorksheetsChemistry, Chapter 12, Stoichiometry, Post Assessment, Retake
Total questions: 25
Worksheet time: 1hrs 5mins
Name
Class
Date
1.
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
2.
What is the measured amount of a product obtained from a chemical reaction?
a)
mole ratio
b)
theoretical yield
c)
percentage yield
d)
actual yield
3.
Mole ratios are obtained from the
a)
balanced chemical equation
b)
periodic table
c)
molar mass
4.
What is the mole ratio of H2O to H3PO4 in the following chemical equation? P4O10 + 6 H2O --> 4 H3PO4
a)
6:4
b)
4:6
c)
1:3
d)
3:1
5.
2Al + 3H2SO4 -> Al2(SO4)3 + 3H2
How many grams of aluminum sulfate would be formed if 250g H2SO4 completely reacted with aluminum?
How many grams of aluminum sulfate would be formed if 250g H2SO4 completely reacted with aluminum?
a)
0.85 g
b)
290 g
c)
450 g
d)
870 g
6.
For the reaction represented by the equation Cl2 + 2KBr → Br2 + 2KCl, how many grams of potassium chloride can be produced from 356 grams potassium bromide?
a)
749 g
b)
225 g
c)
479 g
d)
814 g
7.
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
8.
Identify the limiting reagent when 6.00 g HCl combines with 5.00 g Mg to form MgCl2.
Mg + 2HCl --> MgCl2 + H2
Mg + 2HCl --> MgCl2 + H2
a)
Mg
b)
H2
c)
MgCl2
d)
HCl
9.
How many grams are in 7.8 moles of NaCl?
a)
476grams
b)
460 grams
c)
452 grams
d)
462 grams
10.
Balance the following reaction :
CaC₂(s) + H₂O(l) --> C₂H₂(g) + Ca(OH)₂(aq)
CaC₂(s) + H₂O(l) --> C₂H₂(g) + Ca(OH)₂(aq)
a)
1,2,2,2
b)
1,2,1,1
c)
2,1,1,1
d)
2,1,2,1
11.
Using the following equation:
Fe2O3(s) + 3H2(g) → 2Fe(s) + 3H2O(l)
How many moles of iron can be made from 6 moles H2?
Fe2O3(s) + 3H2(g) → 2Fe(s) + 3H2O(l)
How many moles of iron can be made from 6 moles H2?
a)
4 moles Fe
b)
6 moles Fe
c)
9 moles Fe
d)
2 moles Fe
12.
Identify the limiting reagent when 6.00 moles HCl combines with 5.00 moles Mg to form MgCl2.
1 Mg + 2 HCl --> 1 MgCl2 + 1 H2
1 Mg + 2 HCl --> 1 MgCl2 + 1 H2
a)
Mg
b)
H2
c)
MgCl2
d)
HCl
13.
9. Complete the equation for the percent yield of a chemical reaction:
Percent yield=(________)÷(________)×100%
Percent yield=(________)÷(________)×100%
a)
actual yield; theoretical yield
b)
theoretical yield; actual yield
14.
11.
LiOH + KCl → LiCl + KOH
b) I actually produced 6 grams of lithium chloride and I began this reaction with 20 grams of lithium hydroxide. What is my percent yield?
LiOH + KCl → LiCl + KOH
b) I actually produced 6 grams of lithium chloride and I began this reaction with 20 grams of lithium hydroxide. What is my percent yield?
a)
16.9%
b)
5.91%
c)
1.88%
d)
12.3%
15.
Fe (s) + S (l) --> FeS (s)
In the experiment above, 7.62 g of Fe are allowed to react with 8.67 g of S.
How much FeS is formed?
In the experiment above, 7.62 g of Fe are allowed to react with 8.67 g of S.
How much FeS is formed?
a)
14.8 g
b)
12.2 g
c)
13.7 g
d)
19.9 g
16.
How many particles are in 13.5 grams of Beryllium?
a)
1.5 particles
b)
9 particles
c)
4x1023 particles
d)
9x1023 particles
17.
2 NaClO3 (s) --> 2NaCl (s) +3 O2 (g)
12.00 moles of NaClO3 will produce how many grams of O2?
12.00 moles of NaClO3 will produce how many grams of O2?
a)
256 g of O2
b)
576 g of O2
c)
288 g O2
18.
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%
19.
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
20.
What is the percent yield of the following reaction if 145g of P2O5 reacts with 40 grams of water, but you only collected 112 grams of phosphoric acid? 3 H2O + P2O5 -> 2H3PO4
a)
80%
b)
85%
c)
77%
d)
58%
21.
Name the given compound - Fe2(CO3)3
a)
iron (II) carbonate
b)
Iron (III) carbonate
c)
Iron carbonate
d)
Iron carbonate (II)
22.
Determine the oxidation number of each green coloured element in the following ion : S2O82-
a)
+7
b)
-2
c)
-1
d)
+6
23.
Balance the following equation in acidic medium
aMnO4-(aq) + bC2O42-(aq) →cMn2+(aq) + dCO2(g) + eH2O(l)
The sum of the coefficient a+b+c+d+d
aMnO4-(aq) + bC2O42-(aq) →cMn2+(aq) + dCO2(g) + eH2O(l)
The sum of the coefficient a+b+c+d+d
a)
43
b)
27
c)
29
d)
25
24.
290.23 mg of ethanol (C2H5OH) is reacted with excess oxygen (O2) to provide 481.11 mg of CO2. What is the percentage yield of CO2 in this reaction?
a)
90.0 %
b)
86.7 %
c)
67.8 %
d)
77.8 %
25.
In the equation 2 Al2O3 --> 4 Al + 3 O2, what is the mole ratio of aluminum to oxygen (aluminum is asked for, oxygen is given)?
a)
10/6
b)
3/4
c)
4/3
d)
2/3
100 %
