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WorksheetsChem 2020 Unit 9 Review
Total questions: 70
Worksheet time: 3hrs 46mins
Name
Class
Date
1.
What is the percent by mass of oxygen in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
2.
What is the percent by mass of magnesium in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
3.
What is the percent by mass of sodium in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
4.
What is the percent by mass of chlorine in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
5.
What is the percent by mass of fluorine in CaF2 (gram-formula mass = 78 g/mol)?
a)
24%
b)
49%
c)
51%
d)
65%
6.
What is the percent by mass of calcium in CaF2 (gram-formula mass = 78 g/mol)?
a)
24%
b)
49%
c)
51%
d)
65%
7.
What is the percent composition by mass of sulfur in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
8.
What is the percent composition by mass of magnesium in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
9.
What is the percent composition by mass of oxygen in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
10.
What percentage of the total atomic mass of carbon monoxide (CO) is composed of carbon?
a)
29%
b)
43%
c)
57%
d)
73%
11.
What percentage of the total atomic mass of carbon monoxide (CO) is composed of oxygen?
a)
29%
b)
43%
c)
57%
d)
73%
12.
What percentage of the total atomic mass of magnesium bromide (MgBr2) is composed of magnesium?
a)
13%
b)
43%
c)
63%
d)
87%
13.
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
14.
Which of the following is considered an empirical formula?
a)
CH3COOH
b)
C6H12O6
c)
H2O
15.
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
16.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6O3 and C2H6O2
d)
CH4 and C2H6
17.
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
18.
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
19.
Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?
a)
C2H3O2
b)
CH2O
c)
C2H4O2
d)
C3H8O3
20.
Which one is an empirical formula?
a)
H2O2
b)
C2H6O12
c)
CaCl2
d)
N2O8
21.
What is the empirical formula for C3H8
a)
CH
b)
C3H8
c)
C6H16
d)
CH2.7
22.
What is the molecular formula if the empirical formula is CH2O and the molecular molar mass is 180.18?
a)
CH2O
b)
C2H4O2
c)
C4H8O4
d)
C6H12O6
23.
Given the following: 42.07% Na, 18.89% P, and 39.04% O, determine the empirical formula.
a)
NaPO2
b)
Na2PO3
c)
Na3PO4
d)
NaPO4
24.
Name the following ionic compound: MgSO4*7H2O
a)
magnesium sulfate * hexahydarte
b)
magnesium sulfate hexahydarte
c)
magnesium sulfate heptahydrate
d)
magnesium sulfate* heptahydrate
25.
Na2CO3 · 10H2O is known as sodium sulfate ______
a)
Hydroxide
b)
Hydrate
c)
Decahydrate
d)
None of the above
26.
What is the empirical formula for the following:
32.40% sodium, 22.5% sulfur; 45.1 % oxygen, 37.75% water?
32.40% sodium, 22.5% sulfur; 45.1 % oxygen, 37.75% water?
a)
Na2SO4H6O3
b)
Na2SO4 . 2H2O
c)
Na2SO4 . 3H2O
d)
Na2SO4 . (H2O)3
27.
What is the molar mass of CO2 to the ones place?
a)
12
b)
16
c)
32
d)
44
28.
What are the units for molar mass?
a)
grams
b)
amu
c)
grams/mole
d)
liters
29.
What is the molar mass of B2(CO3)3?
a)
81.632 g/mol
b)
94.842 g/mol
c)
38.822 g/mol
d)
201.648 g/mol
30.
Find the percentage composition of Mg in Mg3(PO4)2.
a)
27.75% Mg
b)
23.57% Mg
c)
48.68% Mg
d)
13.45% Mg
31.
What is the molar mass of Cl2?
a)
17 g/mol
b)
35.5 g/mo;
c)
71.0 g/mol
d)
89 g/mol
32.
What id the molar mass of UF6?
a)
101 g/mol
b)
238 g/mol
c)
257 g/mol
d)
352 g/mol
33.
Calculate the molar mass of KOH.
a)
28 g/mol
b)
56 g/mol
c)
84 g/mol
d)
112 g/mol
34.
What is the empirical formula if you have 36.84% nitrogen and 63.16% oxygen?
a)
NO
b)
N2O3
c)
N2O4
d)
N2O5
35.
What is the empirical formula if you have 88.80% copper and 11.20% oxygen?
a)
Cu3O8
b)
CuO4
c)
Cu2O
d)
Cu4O10
36.
Find the percent composition of Cu2S?
a)
%Cu= 67.987 %S= 32.013
b)
%Cu= 79.854 %S= 20.145
c)
%Cu= 35.946 %S= 64.054
37.
What is the percentage of oxygen in carbon dioxide? (CO2)
a)
27.3%
b)
72.7%
c)
30%
d)
70%
38.
What is the molecular formula for a compound with the empirical formula: K2SO4 and a molecular mass of 696g.
a)
K2SO4
b)
K8SO16
c)
K8S4O8
d)
K8S4O16
39.
What is the empirical formula for the following molecular formula: C6H14
a)
C6H14
b)
C3H7
c)
CH2
d)
CH3
40.
What is the molecular formula of a compound with an empirical formula of C2OH4 and a molecular mass of 88 grams per mole?
a)
C2O4H8
b)
C8O2H4
c)
C4O2H8
d)
C4O8H2
41.
How many significant figures are in 1020?
a)
1
b)
2
c)
3
d)
4
42.
What is the molar mass of NaOH?
a)
40 g/mol
b)
38.989 g/mol
c)
23.998 g/mol
d)
57.004 g/mol
43.
What is the molar mass of AuCl3?
a)
96 g
b)
130 g
c)
232.5 g
d)
303.3 g
44.
How many molecules are in 2.5 mol of NaCl?
a)
1.51x1023
b)
146
c)
4.15
d)
1.51x1024
45.
How many moles are in 22 g of argon?
a)
880 moles
b)
0.55 moles
c)
1.81 moles
d)
5 moles
46.
What is the volume of 2 moles of gas at STP?
a)
22.4 L
b)
44.8 L
c)
11.2 L
d)
2 L
47.
36.0 g of Be contains how many moles?
a)
0.25 mol
b)
4.0 mol
c)
45 mol
d)
320 mol
48.
4.0 moles of H2O would have what mass?
a)
72 g
b)
23 g
c)
68 g
d)
4.5 g
49.
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
50.
How many moles are in 22 g of argon?
a)
880 moles
b)
0.55 moles
c)
1.81 moles
d)
5 moles
51.
How many grams are in 88.1 moles of magnesium?
a)
2141 g
b)
0.3 g
c)
30 g
d)
3.6 g
52.
What is the molar mass of Mn2Se7?
a)
134 g/mole
b)
663 g/mole
c)
189 g/mole
d)
608 g/molw
53.
What is the molar mass of (NH4)2SO4?
a)
66 g/mole
b)
114 g/mole
c)
100 g/mole
d)
132 g/mole
54.
How many moles are in 15 grams of lithium?
a)
0.5 moles
b)
104.1 moles
c)
2.2 moles
d)
50 moles
55.
What are the units for molar mass?
a)
grams
b)
amu
c)
grams/mole
d)
liters
56.
Which of the following is considered an empirical formula?
a)
CH3COOH
b)
C6H12O6
c)
H2O
57.
Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?
a)
C2H3O2
b)
CH2O
c)
C2H4O2
d)
C3H8O3
58.
Carbon monoxide, a deadly gas, has a chemical formula of CO (one carbon atom with one oxygen atom). If you look at the total atomic mass of CO, does carbon or oxygen make up more of the mass?
a)
carbon
b)
oxygen
c)
they are exactly the same
d)
it is impossible to tell
59.
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
60.
What is the best definition for subscript?
a)
The big number that tells you the number of molecules.
b)
The atomic number
c)
The little number that tells the number of atoms for each element.
61.
What is the best definition for coefficient?
a)
The big number that tells you the number of molecules.
b)
The little number that tells the number of atoms for each element.
c)
The atomic number
62.
A chemical formula that shows the actual # and kinds of atoms present in one molecule of a compound is called_________
a)
ionic formula
b)
covalent formula
c)
empirical formula
d)
molecular formula
63.
An empirical formula:
a)
is a formula that calculates the coefficients of a compound in a balanced equation.
b)
is the simplest whole-number ratio of moles of elements in the compound.
64.
N2 + 3H2 → 2NH3
How many moles of hydrogen are needed to react with 2 moles of nitrogen?
How many moles of hydrogen are needed to react with 2 moles of nitrogen?
a)
6
b)
2
c)
3
d)
1
65.
4Si + S8 --> 2Si2S4
a)
Synthesis
b)
Decomposition
c)
Single displacement
d)
Double displacement
66.
3Ca + 2AlCl3 --> 3CaCl2 + 2Al
a)
Synthesis
b)
Decomposition
c)
Single displacement
d)
Double displacement
67.
3KOH + H3PO4 --> K3PO4 + 3H2O
a)
Synthesis
b)
Decomposition
c)
Single displacement
d)
Double displacement
68.
2NO2 --> N2 + 2O2
a)
Synthesis
b)
Decomposition
c)
Single displacement
d)
Combustion
69.
When balancing equations a ____ can be placed to the left of a formula of a substance to make the equations balanced
a)
charge
b)
subscript
c)
random number
d)
coefficient
70.
What coefficient should be used to make the following equation balanced?
N2+O2--> _NO
N2+O2--> _NO
a)
1
b)
2
c)
3
d)
4
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