AP Chemistry Practice Test #1 - Key
Chapters 1, 2, and 3
1. In 1928, 3.3 g of a new element was isolated from 660 kg of the ore molybdenite. The
percent by mass of this element in the ore was:
a.
b.
c.
d.
e.
5%
6.6 %
3.3 %
5.0x10-4 %
2.2 %
2. A quantitative observation
a.
b.
c.
d.
e.
contains a number and a unit.
does not contain a number.
always makes a comparison.
must be obtained through experimentation.
none of these
3. Which of the following is the least probable concerning five measurements taken in the lab?
a.
b.
c.
d.
e.
The measurements are accurate and precise.
The measurements are accurate but not precise.
The measurements are precise but not accurate.
The measurements are neither accurate nor precise.
All of these are equally probable.
4. A scientist obtains the number 0.045006700 on a calculator. If this number actually has four
(4) significant figures, how should it be written?
a.
b.
c.
d.
e.
0.4567
0.4501
0.045
0.04500
0.04501
5. A piece of indium with a mass of 16.61 g is submerged in 46.3 cm3 of water in a graduated
cylinder. The water level increases to 48.6 cm3. The correct value for the density of indium
from these data is:
a.
b.
c.
d.
e.
7.222 g/cm3
7.2 g/cm3
0.14 g/cm3
0.138 g/cm3
more than 0.1 g/cm3 away from any of these values.
6. Using the rules of significant figures, calculate the following: 4.0021 – 1.013
a.
b.
c.
d.
e.
2.989
3
2.9891
2.99
3.0
7. Convert 4324 mL to qts. (1 L = 1.06 qt)
a.
b.
c.
d.
e.
4583 qts
4.079 qts
4.079e-3 qts
4079 qts
4.583 qts
8. A monolayer containing 3.15e-6 g of oleic acid has an area of 20.0 cm2. The density of oleic
acid is 0.895 g/mL. What is the thickness of the monolayer (the length of an oleic acid
molecule)?
a.
b.
c.
d.
e.
7.04e-5 cm
5.68e6 cm
1.41e-7 cm
1.76e-7 cm
1.41e-7 cm
9. The density of gasoline is 0.7025 g/mL at 20oC. When gasoline is added to water:
a.
b.
c.
d.
e.
it will float on top.
it will sink to the bottom.
it will mix so you can’t see it.
the mixture will improve the running of the motor.
none of these things will happen.
10. A freighter carrying a cargo of uranium hexafluoride sank in the English Channel late August
1984. The cargo of uranium hexafluoride weighed 2.251e8 kg and was contained in 30
drums, each having a volume of 1.62x106L. What is the density (g/mL) of uranium
hexafluoride?
a.
b.
c.
d.
e.
1.39 g/mL
4.63 g/mL
2.25 g/mL
0.216 g/mL
46.3 g/mL
11. Which of the following pairs of compounds can be used to illustrate the law of multiple
proportions?
a.
b.
c.
d.
e.
12.
NH4 and NH4Cl
ZnO2 and ZnCl2
H2O and HCl
NO and NO2
CH4 and CO2
40
2+
20 Ca
a.
b.
c.
d.
e.
has
20 protons, 20 neutrons, and 18 electrons.
22 protons, 20 neutrons, and 20 electrons.
20 protons, 22 neutrons, and 18 electrons.
22 protons, 18 neutrons, and 18 electrons.
20 protons, 20 neutrons, and 22 electrons.
13. Which of the following name(s) is(are) correct?
1) sulfide S22) ammonium chloride NH4Cl
3) acetic acid HC2H3O2
4) barium oxide BaO
a.
b.
c.
d.
e.
all
none
1, 2
3, 4
1, 3, 4
14. Which of the following statements is (are) true?
a.
b.
18
O
148
6C
c.
18 28O
and
and
19
F
149
7N
have the same number of neutrons.
are isotopes of each other because their mass numbers are the same.
has the same number of electrons as
20
10 Ne .
d. a and b
e. a and c
15. The formula for calcium bisulfate is
a.
b.
c.
d.
e.
Ca(SO4)2
CaS2
Ca(HSO4)2
Ca2HSO4
Ca2S
16. All of the following are in aqueous solution. Which is incorrectly named?
a.
b.
c.
d.
e.
H2SO4, sulfuric acid
H3PO4, phosphoric acid
H3PO4, phosphoric acid
HCN, cyanic acid
HCl, hydrochloric acid
17. Write the names of the following compounds:
a)
b)
c)
d)
e)
FeSO4
NaC2H3O2
KNO2
Ca(OH)2
NiCO3
__iron(II) sulfate_______
__sodium acetate_______
__potassium nitrite_____
_ calcium hydroxide___
__nickel(II) carbonate__
18. You are given a compound with the formula MCl2, in which M is a metal. You are told that
the metal ion has 26 electrons. What is the identity of the metal?
a.
b.
c.
d.
e.
Co
Al
Fe
Cr
Ni
19. The atomic mass of rhenium is 186.2. Given that 37.1% of natural rhenium is rhenium-185,
what is the other stable isotope?
a.
183
75 Re
b.
187
75
Re
c.
189
75
Re
d.
181
75 Re
e.
190
75
Re
20. Naturally occurring copper exists in two isotopic forms: Copper-63 and Copper-65. The
atomic mass of copper is 63.55 amu. What is the approximate natural abundance of Copper63?
a.
b.
c.
d.
e.
63%
90%
70%
50%
30%
21. For which compound does 0.256 mole weigh 12.8 g?
a.
b.
c.
d.
e.
C2H4O
CO2
CH3Cl
C2H6
none of these
22. A given sample of xenon fluoride contains molecules of a single type XeFn, where n is some
whole number. Given that 9.03 x 1020 molecules of XeFn weigh .311 g, calculate n.
a.
b.
c.
d.
1
2
4
none of these
23. How many atoms of hydrogen are present in 5.5 g of water?
a.
b.
c.
d.
e.
1.8e23
1.6e24
6.6e24
3.7e23
0.61
24. What is the molar mass of cryolite (Na3AlF6)?
a.
b.
c.
d.
e.
209.9
185.3
210.0
104.2
68.97
25. What is the coefficient for water when the following equation is balanced?
As(OH)3(s) + H2SO4(aq) → As2(SO4)3(aq) + H2O(l)
a.
b.
c.
d.
e.
1
2
4
6
12
26. You take an aspirin tablet (a compound consisting solely of carbon, hydrogen, and oxygen)
with a mass of 1.00 g, burn it in air, and collect 2.20 g of carbon dioxide and 0.400 g of
water. The molar mass of aspirin is between 170 and 190 g/mol. The molecular form of
aspirin is
a.
b.
c.
d.
e.
C6H8O5
C9H8O4
C8H10O5
C10H6O4
none of these
27. Suppose the reaction Ca3(PO4)2 + 3H2SO4 → 3CaSO4 + 2H3PO4 is carried out starting with
103 g of Ca3(PO4)2 and 26.7 g of H2SO4. How much phosphoric acid will be produced?
a.
b.
c.
d.
e.
26.7 g
17.8 g
239.8 g
40.0 g
65.1 g
28. An oxide of iron has the formula Fe3O4. What mass percent of iron does it contain?
a.
b.
c.
d.
e.
0.72%
28%
30.%
70.%
72%
29. A chloride of rhenium contains 63.6% rhenium. What is the formula of this compound?
a.
b.
c.
d.
e.
ReCl
ReCl3
ReCl5
ReCl7
Re2Cl3
30. The empirical formula of styrene is CH; it molar mass is 104.1. What is the molecular
formula of styrene?
a.
b.
c.
d.
e.
C2H4
C8H8
C10H12
C6H6
none of these
31. Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass. What is the empirical
formula?
a.
b.
c.
d.
e.
C3H5O2
C3H3O4
C2HO3
C2H5O4
C3HO3
32. Vitamin C contains the elements C, H, and O. It is known to contain 40.9% C and 4.58% H
by mass. The molar mass of vitamin C has been found to be about 180. The molecular
formula for vitamin C is:
a.
b.
c.
d.
C2H3O2
C3H4O3
C4H6O4
C6H8O6
33. When 223.0 g of ethylene (C2H4) burns in oxygen to given carbon dioxide and water, how
many grams of CO2 are formed?
a.
b.
c.
d.
e.
699.7 g
349.9 g
174.9 g
7.95 g
286.4 g
34. Determine the coefficient for O2 when the following equation is balanced in standard form
(smallest whole number integers)
C4H10(g) + O2(g) → CO2(g) + H2O(g)
a.
b.
c.
d.
e.
4
8
10
13
20
35. wPCl5 + xH2O → yPOCl3 + zHCl
The above equation is properly balanced when
a.
b.
c.
d.
e.
w = 1, x = 2, y = 2, z = 4
w = 2, x = 2, y = 2, z = 2
w = 2, x = 2, y = 2, z = 1
w = 1, x = 1, y = 1, z = 2
none of these
36. A 6.35-g sample of potassium chlorate was decomposed according to the following equation:
2KClO3 → 2KCl + 3O2
How many moles of oxygen are formed?
a.
b.
c.
d.
e.
2.49 g
0.0518 mol
0.0345 mol
0.0777 mol
none of these
37. How many grams of H2O will be formed when 32.0 g H2 is mixed with 18.0 g of O2 and
allowed to react to form water?
a.
b.
c.
d.
e.
20.3 g
286 g
10.1 g
5.1 g
144 g
38. A 15-g sample of lithium is reacted with 15 g of fluorine to form lithium fluoride: 2Li + F2
→ 2LiF. After the reaction is complete, what will be present?
a.
b.
c.
d.
e.
2.16 moles lithium fluoride only
0.789 moles lithium fluoride only
2.16 moles lithium fluoride and 0.395 moles fluorine
0.789 moles lithium fluoride and 1.37 moles lithium
none of these
39. The following two reactions are important in the blast furnace production of iron metal from
iron ore (Fe2O3):
2C(s) + O2(g) → 2CO(g)
Fe2O3 + 3CO(g) → 2Fe + 3CO2(g)
Using these balanced reactions, how many moles of O2 are required for the production of
2.35 kg of Fe?
a.
b.
c.
d.
e.
31.6 moles
14.0 moles
126 moles
42.1 moles
1.76 moles
40. The reaction of 11.9 g of CHCl3 with excess chlorine produced 13.3 g of CCl4, carbon
tetrachloride:
2CHCl3 + 2Cl2 → 2CCl4 + 2HCl
What is the percent yield?
a.
b.
c.
d.
e.
100.%
43.4%
86.8%
112%
57.8%