Directions: 1. SHOW ALL WORK in the space provided or your answer is VOID! 1. How many formula units are there in 2.5 moles of MgCl2? A) 2.5 B) 7.5 C) 1.5  1024 D) 4.5  1024 E) 4.2  10–24 Show your work below or ZERO POINTS! 2. How many chloride ions are present in 0.100 mol of MgCl2? A) 0.200 Cl– ions D) 3.32  10–25 Cl– ions B) 6.02  1022 Cl– ions E) 3.01  1024 Cl– ions C) 1.20  1023 Cl– ions Show your work below or ZERO POINTS 3. How many nitrate ions are present in 0.200 mol of Zn(NO3)2? A) 1.20  1023 NO3– ions D) 6.64  10–25 NO3– ions B) 2.41  1023 NO3– ions E) 0.400 NO3– ions C) 3.01  1024 NO3– ions Show your work below or ZERO POINTS 4. Consider the following chemical equations. Select the equations that represent chemical reactions, rather than physical changes. I. CH4(g) + O2(g)  CO2(g) + H2O(g) II. C2H5OH(l)  C2H5OH(g) III. NaOH(s)  Na+(aq) + OHˉ(aq) A) I, II, and III D) II and III only B) I and II only E) I only C) I and III only Show your work below or ZERO POINTS 5. Calculate the molar mass of CuSO4·5H2O. A) 159.62 g/mol D) 185.72 g/mol B) 249.70 g/mol E) 446.48 g/mol C) 177.64 g/mol Show your work below or ZERO POINTS 6. If 4.05  1023 molecules of a substance have a mass of 86.2 g, what is the molar mass of the substance? A) 128 g/mol D) 4.70  1021 g/mol B) 3.49  1025 g/mol E) 58.0 g/mol C) 2.13  1022 g/mol Show your work below or ZERO POINTS 7. Consider the following chemical equations. Select the equations that represent chemical reactions, rather than physical changes. I. 2NO(g) + O2(g)  2NO2(g) II. CO2(s)  CO2(g) III. Pb(NO3)2(aq) + 2AgCl(aq)  PbCl2(s) + 2AgNO3(aq) A) I, II, and III D) II and III only B) I and II only E) I only C) I and III only Show your work below or ZERO POINTS 8. Write a complete, balanced equation for the reaction that occurs when sodium metal reacts with water to form hydrogen gas and aqueous sodium hydroxide. A) Na(s) + H2O(l)  NaOH(aq) + H(g) B) Na(s) + H2O(l)  NaOH(aq) + H2(g) C) Na(s) + 2H2O(l)  NaOH(aq) + 2H2(g) D) Na(s) + 2H2O(l)  2NaOH(aq) + 2H2(g) E) 2Na(s) + 2H2O(l)  2NaOH(aq) + H2(g) Show your work below or ZERO POINTS 9. Zinc metal will react with aqueous hydrochloric acid to produce aqueous zinc chloride and hydrogen gas. Write a complete, balanced equation for this reaction. A) Zn(s) + HCl(aq)  ZnCl(aq) + H(g) B) Zn(s) + HCl(aq)  ZnCl(aq) + H2(g) C) Zn(s) + 2HCl(aq)  ZnCl(aq) + H2(g) D) Zn(s) + 2HCl(aq)  ZnCl2(aq) + H2(g) E) 2Zn(s) + 2HCl(aq)  2ZnCl(aq) + H2(g) Show your work below or ZERO POINTS 10. Calculate the number of moles of NaHCO3 (sodium bicarbonate, or baking soda) in a 5.0 g sample of this substance. A) 0.096 mole D) 3.6  1022 moles B) 0.060 mole E) 2.8  1023 mole C) 420 moles Show your work below or ZERO POINTS 11. Calculate the number of moles of NaOH (sodium hydroxide, an ingredient in drain cl.

1. Directions:
1. SHOW ALL WORK in the space provided or your answer is
VOID!
1.
How many formula units are there in 2.5 moles of MgCl2?
10–24
Show your work below or ZERO POINTS!
2.
How many chloride ions are present in 0.100 mol of MgCl2?
A)
0.200 Cl– ions
D)
–25 Cl– ions
B)
– ions
E)
– ions
C)
– ions

2. Show your work below or ZERO POINTS
3.
How many nitrate ions are present in 0.200 mol of Zn(NO3)2?
A)
– ions
D)
–25 NO3– ions
B)
– ions
E)
0.400 NO3– ions
C)
– ions
Show your work below or ZERO POINTS
4.
Consider the following chemical equations. Select the
equations that represent chemical reactions, rather than physical
changes.

3. A)
I, II, and III
D)
II and III only
B)
I and II only
E)
I only
C)
I and III only
Show your work below or ZERO POINTS
5.
Calculate the molar mass of CuSO4·5H2O.
A)
159.62 g/mol
D)
185.72 g/mol

4. B)
249.70 g/mol
E)
446.48 g/mol
C)
177.64 g/mol
Show your work below or ZERO POINTS
6.
substance have a mass of 86.2 g,
what is the molar mass of the substance?
A)
128 g/mol
D)
B)
E)
58.0 g/mol
C)

5. Show your work below or ZERO POINTS
7.
Consider the following chemical equations. Select the
equations that represent chemical reactions, rather than physical
changes.
A)
I, II, and III
D)
II and III only
B)
I and II only
E)
I only
C)
I and III only

6. Show your work below or ZERO POINTS
8.
Write a complete, balanced equation for the reaction that occurs
when sodium metal reacts with water to form hydrogen gas and
aqueous sodium hydroxide.
A)
H(aq) + H(g)
B)
C)
D)
E)
Show your work below or ZERO POINTS
9.
Zinc metal will react with aqueous hydrochloric acid to produce
aqueous zinc chloride and hydrogen gas. Write a complete,
balanced equation for this reaction.

7. A)
B)
C)
D)
Zn(s) + 2
E)
Show your work below or ZERO POINTS
10.
Calculate the number of moles of NaHCO3 (sodium bicarbonate,
or baking soda) in a 5.0 g sample of this substance.
A)
0.096 mole
D)
moles
B)
0.060 mole
E)

8. C)
420 moles
Show your work below or ZERO POINTS
11.
Calculate the number of moles of NaOH (sodium hydroxide, an
ingredient in drain cleaners and oven cleaners) in a 10.0 g
sample of this substance.
A)
1.51
D)
B)
E)
0.250 mole
C)
0.208 mole
Show your work below or ZERO POINTS
12.

9. Calculate the number of moles of CaCO3 (calcium carbonate, or
limestone) in a 20.0 g sample of this substance.
A)
moles
D)
B)
0.200 mole
E)
C)
0.294 mole
Show your work below or ZERO POINTS
13.
When solid ammonium carbonate is heated, it decomposes to
form ammonia gas, carbon dioxide gas, and water vapor, so that
the solid completely disappears. Write a complete, balanced
equation for this reaction.
A)
B)

10. C)
D)
E)
Show your work below or ZERO POINTS
14.
CO2(g) + H2O(g).
A)
B)
C)
C2H
D)

11. E)
Show your work below or ZERO POINTS
15.
NO2(g) + H2O(g).
A)
4NH3(g)
B)
C)
D)
E)
Show your work below or ZERO POINTS
16.
Balance the following skeletal equation:

12. A)
B)
C)
D)
2Ba(NO3)2(aq) + 2K2SO4(
E)
Show your work below or ZERO POINTS
17.
After the following equation is properly balanced, what is the
coefficient in front of O2?
A) 2 B) 3 C) 8 D) 12 E) 16

13. Show your work below or ZERO POINTS
18.
A reaction which has two elements as reactants and one
compound as a product is:
A)
a decomposition reaction.
D)
a double-displacement reaction.
B)
a combination reaction.
E)
a combustion reaction.
C)
a single-displacement reaction.
Show your work below or ZERO POINTS
19.
A solution of silver nitrate is mixed with a solution of sodium
chloride, resulting in a precipitate of silver chloride and a
solution of sodium nitrate. The class of this reaction is:
A)
decomposition reaction.
D)
double-displacement reaction.

14. B)
combination reaction.
E)
combustion reaction.
C)
single-displacement reaction.
Show your work below or ZERO POINTS
20.
A piece of magnesium metal is placed in a solution of
hydrochloric acid, resulting in the formation of hydrogen gas
and a solution of magnesium chloride. The class of this
reaction is:
A)
decomposition reaction.
D)
double-displacement reaction.
B)
combination reaction.
E)
combustion reaction.
C)
single-displacement reaction.

15. Show your work below or ZERO POINTS
21.
The class of the reaction shown in the figure is:
A)
decomposition reaction.
D)
double-displacement reaction.
B)
combination reaction.
E)
combustion reaction.
C)
single-displacement reaction.
Show your work below or ZERO POINTS
22.
Write and balance the equation for the decomposition reaction
that occurs when Mercury(II) oxide decomposes to its elements.
A)

16. D)
HgO2(s)
B)
E)
C)
Show your work below or ZERO POINTS
23.
When writing a net ionic equation, how would Mg(NO3)2(aq)
be represented?
A)
Mg2+(aq) + 2NO3–(aq)
D)
Mg(aq) + N2(aq) + 3O2(aq)
B)
Mg2+(aq) + NO3–(aq)
E)
Mg2+(aq) + 2N3–(aq) + 6O2–(aq)
C)
Mg2+(aq) + (NO3)2–(aq)

17. Show your work below or ZERO POINTS
24.
Write and balance a net ionic equation for the reaction between
hydrochloric acid and potassium hydroxide.
A)
B)
C)
D)
E)
Show your work below or ZERO POINTS
25.
Write and balance a net ionic equation for the reaction between
iron(II) chloride and potassium hydroxide to form iron(II)
hydroxide and potassium chloride.

18. A)
B)
C)
D)
E)
Show your work below or ZERO POINTS
26.
When potassium metal is placed in water, will a reaction occur?
If so, what is the balanced equation for the reaction?
A)
No reaction will occur.
B)
C)

19. D)
E)
Show your work below or ZERO POINTS
27.
When iron metal is placed into a solution of hydrochloric acid,
will a reaction occur? If so, what is the balanced equation for
the reaction?
A)
No reaction will occur.
B)
C)
D)
Yes. F
Show your work below or ZERO POINTS
28.

20. When copper metal is placed in a solution of zinc nitrate, will a
reaction occur? If so, what is the balanced equation for the
reaction?
A)
aq) + ZnNO3(aq)
B)
C)
D)
No reaction will occur.
E)
Show your work below or ZERO POINTS
29.
When heated, calcium carbonate (limestone) undergoes a
decomposition reaction. Write a balanced equation for this
reaction.
A)
D)

21. B)
E)
C)
CaCO3(
Show your work below or ZERO POINTS
30.
Which of the following ionic compounds would be expected to
be insoluble in water?
A) KCl B) PbI2 C) NH4NO3 D) CuSO4 E)
NaCH3CO2
Show your work below or ZERO POINTS
31.
Which of the following ionic compounds would be expected to
be insoluble in water?
A) CaS B) Ca(NO3)2 C) Na2SO4 D) KI E) NaOH
Show your work below or ZERO POINTS
32.

22. A 5.05 g sample of quartz (SiO2) contains 2.36 g of silicon.
What are the percents of silicon and oxygen in quartz?
A)
53.3% Si and 46.7% O
B)
46.7% Si and 53.3% O
C)
29.9% Si and 70.1% O
D)
70.1% Si and 29.9% O
E)
46.7% Si, and insufficient information to calculate % O
Show your work below or ZERO POINTS
33.
A 6.25 g sample of magnetite (Fe3O4) contains 4.52 g of Fe.
What are the percents of iron and oxygen in magnetite?
A)
28.6% Fe and 71.4% O
D)
27.7% Fe and 72.3% O

23. B)
42.8% Fe and 57.2% O
E)
57.2% Fe and 42.8% O
C)
72.3% Fe and 27.7% O
Show your work below or ZERO POINTS
34.
A 7.50 g sample of pyrite (FeS2) contains 3.49 g of iron. What
are the percents of iron and sulfur in pyrite (also known as
“Fool's Gold” because of its golden color)?
A)
57.4% Fe and 42.6% S
D)
46.5% Fe and 53.5% S
B)
66.7% Fe and 33.3% S
E)
53.5% Fe and 46.5% S
C)
33.3% Fe and 66.7% S

24. Show your work below or ZERO POINTS
35.
Malachite is a green colored mineral that is 57.5% copper.
What mass of copper is present in a 250.0 g sample of
malachite?
A) 63.6 g B) 127 g C) 435 g D) 36.5 g E) 144 g
Show your work below or ZERO POINTS
36.
Barium sulfate is a compound used to assist in diagnosing
medical problems through x-ray analysis and is 58.8% barium.
What mass of barium is present in a 620 mg tablet of barium
sulfate?
A) 81 mg B) 230 mg C) 360 mg D) 1100 mg E) 11
mg
Show your work below or ZERO POINTS
37.
Which of the following statements is incorrect?
A)
PH3 has 3 times as many hydrogen atoms as phosphorus atoms.
B)
MgO has an equal number of magnesium ions and oxygen ions.

25. C)
BaBr2 has half as many barium ions as bromide ions.
D)
N2O5 has 2.5 times as many nitrogen atoms as oxygen atoms.
E)
SF4 has 4 times as many fluorine atoms as sulfur atoms.
Show your work below or ZERO POINTS
38.
Which of the following statements is incorrect?
A)
CH4 has ¼ as many carbon atoms as hydrogen atoms.
B)
H2O has twice as many oxygen atoms as hydrogen atoms.
C)
SO3 has three times as many oxygen atoms as sulfur atoms.
D)
P4O10 has 2.5 times as many oxygen atoms as phosphorus
atoms.

26. E)
SrF2 has twice as many fluoride ions as strontium ions.
Show your work below or ZERO POINTS
39.
Which of the following statements is incorrect?
A)
N2H4 has four times as many hydrogen atoms as nitrogen
atoms.
B)
SF4 has ¼ as many sulfur atoms as fluorine atoms.
C)
SO2 has twice as many oxygen atoms as sulfur atoms.
D)
Ca(NO3)2 has six times as many oxygen atoms as calcium ions.
E)
H2SO4 has twice as many oxygen atoms as hydrogen atoms.
Show your work below or ZERO POINTS
40.
How many moles are in a sample of ethylene glycol (commonly
found in antifreeze), HOCH2CH2OH, that has a volume of
250.0 mL? The molar mass and density of ethylene glycol are
62.07 g/mol and 1.11 g/mL, respectively.

27. A)
4.47 mol
D)
B)
0.276 mol
E)
C)
3.63 mol
Show your work below or ZERO POINTS
41.
How many oxygen atoms are in 75.0 g of SO3?
A)
225 atoms
D)
B)
0.937 atoms
E)

28. C)
5.
Show your work below or ZERO POINTS
42.
Show your work below or ZERO POINTS
43.
les of NO2?
12 g
Show your work below or ZERO POINTS
44.
Which of the following statements regarding empirical
formulas, molecular formulas, and percent composition is
correct?
A)
The compounds NO2 and N2O4 have the same empirical
formula.

29. B)
The compounds NO2 and N2O4 have the same molecular
formula.
C)
The empirical formula of H2O2 is H2O.
D)
The empirical formula of N2O5 is NO2.5.
E)
The compounds PCl3 and PCl5 would have the same percent
composition.
Show your work below or ZERO POINTS
45.
Methyl butyrate is a compound that is partially responsible for
the flavor of apples. It consists of 58.80% C, 9.87% H, and
31.33% O. What is the empirical formula of methyl butyrate?
A) C6H10O3 B) C5H10O2 C) CH2O D) C4.9H9.8O1.9
E) C4H9O2
Show your work below or ZERO POINTS
46.
Acetaminophen is the active ingredient in Tylenol. It consists
of 63.56% C, 6.00% H, 9.27% N, and 21.17% O. What is the
empirical formula of acetaminophen?

30. A) C8H8NO2 B) C8H9NO2 C) C6HNO2 D)
C5.3H5.9N0.7O1.3 E) C4H4NO
Show your work below or ZERO POINTS
47.
Acetic acid has a molar mass of 60.05 g/mol and consists of
40.00% C, 6.714% H, and 53.29% O. What is the molecular
formula of acetic acid?
A) C3.33H6.66O3.33 B) C3H6O3 C) CH2O D)
C2H4O2 E) CH3O
Show your work below or ZERO POINTS
48.
Butyric acid has a very unpleasant odor. It is present in some
rotting foods, body odor and vomit. Butyric acid has a molar
mass of 88.10 g/mol and consists of 54.53% C, 9.153% H, and
36.32% O. What is the molecular formula of butyric acid?
A) CH2O0.5 B) CH2O C) CH4O D) C2H4O E)
C4H8O2
Show your work below or ZERO POINTS
49.
Acetaminophen is the active ingredient in Tylenol. It consists
of 63.56% C, 6.00% H, 9.27% N, and 21.17% O. What is the
empirical formula of acetaminophen?

31. A) C8H8NO2 B) C8H9NO2 C) C6HNO2 D)
C5.3H5.9N0.7O1.3 E) C4H4NO
Show your work below or ZERO POINTS
50.
Which of the following statements regarding empirical and
molecular formulas is correct?
A)
Information on percent composition is all that is necessary to
determine both an empirical and a molecular formula.
B)
A compound with an empirical formula of CH2O and a molar
mass of 90 g/mol would have a molecular formula of C3H6O3.
C)
The compounds C2H4 and C3H6 have different empirical
formulas.
D)
The formula Ca2Cl4 is the correct empirical formula for
calcium chloride.
E)
The compound benzene has a molecular formula of C6H6, so its
empirical formula would be C3H3.

32. Show your work below or ZERO POINT
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