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WorksheetsUnit 7 Review (Stoichiometry)
Total questions: 39
Worksheet time: 3hrs 11mins
Name
Class
Date
1.
How many molecules are in 2.5 mol of NaCl?
a)
1.51x1023
b)
146
c)
4.15
d)
1.51x1024
2.
How many molecules of sugar (C6H12O6) are in a mole?
a)
24 molecules
b)
180 molecules
c)
180 g
d)
6.02 x 1023 molecules
3.
How many atoms of carbon are in 6.00g of carbon?
a)
1.20x1024atoms C
b)
6.02x1023atoms C
c)
3.01x1023atoms C
d)
1.50x1023atoms C
4.
What are the units for molar mass?
a)
grams
b)
amu
c)
grams/mole
d)
liters
5.
What is the molar mass of table salt (NaCl)?
a)
116.886 g/mol
b)
35.453 g/mol
c)
22.990 g/mol
d)
58.443 g/mol
6.
What is the mass of 0.89 mol of CaCl2?
a)
111 grams
b)
0.008 grams
c)
98.9 grams
d)
none of the choices
7.
What is the mass of 0.89 mol of CaCl2?
a)
111 grams
b)
0.008 grams
c)
98.9 grams
d)
none of the choices
8.
What is the molar mass of NaOH?
a)
368 g/mole
b)
40 g/mole
c)
57 g/mole
d)
23 g/mole
9.
What is the mass of one mole of AuCl3?
a)
96g
b)
130g
c)
232.5g
d)
303.5g
10.
36.0 g of Be contains how many moles?
a)
0.25 mol
b)
4.0 mol
c)
45 mol
d)
320 mol
11.
A mass of 6 g of Carbon contains
a)
1 mole of C
b)
2 moles of C
c)
0.5 moles of C
d)
72 moles of C
12.
What is the molar mass of (NH4)2SO4?
a)
66 g/mole
b)
114 g/mole
c)
100 g/mole
d)
132 g/mole
13.
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
14.
2 KClO3 → 2 KCl + 3 O2
How many moles of oxygen are produced when 6.7 moles of KClO3 decompose completely?
How many moles of oxygen are produced when 6.7 moles of KClO3 decompose completely?
a)
6.7 mol
b)
1.0 mol
c)
10.1 mol
d)
4.5 mol
15.
2Na + 2H2O → 2NaOH+ H2
How many grams of hydrogen are produced if 120 g of Na are available?
How many grams of hydrogen are produced if 120 g of Na are available?
a)
5.2 g
b)
2.6 g
c)
690 g
d)
45 g
16.
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
17.
2 CO (g) + O2(g) → 2 CO2 (g)
In the formation of CO2 from CO and oxygen, how many Liters of CO2 are produced by the reaction of 8 mols of O2 with an excess of carbon monoxide?
In the formation of CO2 from CO and oxygen, how many Liters of CO2 are produced by the reaction of 8 mols of O2 with an excess of carbon monoxide?
a)
0.178 L
b)
358.4 Liters
c)
704 grams
d)
0.36 grams
18.
SiO2 + 3C → SiC + 2CO
I need to add 8 moles of Carbon to the reaction. How many grams of Carbon should I weigh?
I need to add 8 moles of Carbon to the reaction. How many grams of Carbon should I weigh?
a)
96 g
b)
0.67 g
c)
2.67 g
d)
48 g
19.
A chemist interested in the efficiency of a chemical reaction would calculate the
a)
mole ratio
b)
rate of reaction
c)
percent yield
d)
energy released
20.
What is a Excess Reagent?
a)
amount you end with
b)
what you run out of first
c)
what you have left over
d)
what you start with
21.
CH4 + 2 O2 → CO2 + 2 H2O
How many moles of carbon dioxide are produced from the combustion of 110 g of CH4?
How many moles of carbon dioxide are produced from the combustion of 110 g of CH4?
a)
13.7 mol
b)
2.75 mol
c)
6.11 mol
d)
6.85 mol
22.
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
23.
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
24.
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
25.
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
26.
What is the limiting reactant if 10 moles of NH3 react with 30.0 moles of NO?
4NH3+6NO --> 5N2 + 6H2O
4NH3+6NO --> 5N2 + 6H2O
a)
NH3
b)
NO
c)
N2
d)
water
27.
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
28.
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%
29.
How many grams of FeS are formed from 7.62g of Fe reacted with excess S?
a)
3.82g
b)
7.62g
c)
12.2g
d)
11.4g
30.
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%
31.
What is the percent by mass of oxygen in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
32.
What is the percent by mass of sodium in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
33.
What is the percent by mass of chlorine in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
34.
In which compound is the percent composition by mass of Cl equal to 42%?
a)
HClO (gram formula mass = 52 g/mol)
b)
HClO2 (gram formula mass = 68 g/mol)
c)
HClO3 (gram formula mass = 84 g/mol)
d)
HClO4 (gram formula mass = 100 g/mol)
35.
A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?
a)
Mg4N3
b)
MgN2
c)
Mg3N2
d)
MgN
36.
Which of the following is considered an empirical formula?
a)
CH3COOH
b)
C6H12O6
c)
H2O
37.
You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.
a)
SO
b)
SO2
c)
SO3
d)
SO4
38.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6O3 and C2H6O2
d)
CH4 and C2H6
39.
A formula with the lowest whole # ratio of elements in a compound is called
a)
Molecular Formula
b)
Chemical Formula
c)
Empirical Formula
d)
Distance Formula
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