Review Exam 2
1.Naturally occurring element X exists in three isotopic forms: X-28 (27.977 amu, 92.23% abundance),
X-29 (28.976 amu, 4.67% abundance), and X-30 (29.974 amu, 3.10% abundance). Calculate the
atomic weight of X.
A) 28.09 amu
B) 48.63 amu
C) 27.16 amu
D) 28.97 amu
E) 86.93 amu
2.What is the mass of 4 atom(s) of copper in grams?
A) 254.2 g
B) 2.37  1021 g
C) 9.57  10–24 g
D) 6.022  1023 g
E) 4.22  10–22 g
3.Phosphoric acid can be prepared by reaction of sulfuric acid with “phosphate rock” according to the
equation:
Ca3(PO4)2 + 3H2SO4  3CaSO4 + 2H3PO4
How many oxygen atoms are there in 1.75 ng of Ca3(PO4)2?
A) 3.40  1012
B) 1.36  1013
C) 8.43  1015
D) 2.72  1022
E) 2.72  1013
4.How many atoms of hydrogen are present in 7.63 g of ammonia?
A) 2.70  1023
B) 1.52  1024
C) 1.38  1025
D) 8.09  1023
E) 1.12  1020
5.The molar mass of an insecticide, dibromoethane, is 187.9 g/mol. Its molecular formula is C2H4Br2.
What percent by mass of bromine does dibromoethane contain?
A) 42.52%
B) 2.14%
C) 85.05%
D) 12.78%
E) 6.39%
6.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 water. The molar mass
of aspirin is between 170 and 190 g/mol. The molecular formula of aspirin is
A) C6H8O5
B) C9H8O4
C) C8H10O5
D) C10H6O4
E) none of these
7.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 g/mol. The molecular formula for
vitamin C is:
A) C2H3O2
B) C3H4O3
C) C4H6O4
D) C6H8O6
E) C14H18
8.Which of the following equations is not balanced?
A) 4Al + 3O2  2Al2O3
B) C2H6 + O2  2CO2 + 3H2O
C) 2KClO3  2KCl + O2
D) 4P4 + 5S8  4P4S10
E) P4 + 5O2  P4O10
9.What is the sum of the coefficients of the following equation when it is balanced using smallest whole
numbers?
NaNH2 + NaNO3  NaN3 +NaOH + NH3
A) 5
B) 6
C) 7
D) 8
E) 9
10.You heat 3.869 g of a mixture of Fe3O4 and FeO to form 4.141 g Fe2O3. The mass of oxygen reacted
is
A) 0.272 g
B) 0.476 g
C) 1.242 g
D) 1.000 g
E) none of these
11.Phosphoric acid can be prepared by reaction of sulfuric acid with “phosphate rock” according to the
equation:
Ca3(PO4)2 + 3H2SO4  3CaSO4 + 2H3PO4
Suppose the reaction is carried out starting with 129 g of Ca3(PO4)2 and 97.4 g of H2SO4. Which
substance is the limiting reactant?
A) Ca3(PO4)2
B) H2SO4
C) CaSO4
D) H3PO4
E) none of these
12.Consider the fermentation reaction of glucose:
A 1.00-mole sample of C6H12O6 was placed in a vat with 100 g of yeast. If 32.3 grams of
C2H5OH was obtained, what was the percent yield of C2H5OH?
A) 35.1%
B) 17.5%
C) 100%
D) 32.3%
E) none of these
13.Which of the following is a strong acid?
A) HF
B) KOH
C) HClO4
D) HClO
E) HBrO
14.Which of the following is not a strong base?
A) Ca(OH)2
B) KOH
C) NH3
D) LiOH
E) Sr(OH)2
15.A 16.4-g sample of HF is dissolved in water to give 2.0  102 mL of solution. The concentration of the
solution is:
A)
B)
C)
D)
E)
0.82 M
0.16 M
0.08 M
4.1 M
8.2 M
16.How many grams of NaCl are contained in 350. mL of a 0.287 M solution of sodium chloride?
A) 16.8 g
B) 5.87 g
C) 11.74 g
D) 100.5 g
E) none of these
17.What volume of 18 M sulfuric acid must be used to prepare 2.30 L of 0.145 M H2SO4?
A) 19 mL
B) 0.33 mL
C) 1.1  103 mL
D) 2.9 mL
E) 6.0 mL
18.Phosphoric acid, H3PO4, is a triprotic acid. What is the total number of moles of H+ available for
reaction in 2.50 L of 0.700 M H3PO4?
A) 0.233 mole
B) 2.10 mole
C) 0.583 mole
D) 3.00 moles
E) 5.25 moles
19.The following reactions
ZnBr2(aq) + 2AgNO3(aq)  Zn(NO3)2(aq) + 2AgBr(s)
KBr(aq) + AgNO3(aq)  AgBr(s) + KNO3(aq)
are examples of
A) oxidation-reduction reactions
B) acid-base reactions
C) precipitation reactions
D) A and C
E) none of these
20.Which of the following compounds is soluble in water?
A) Ni(OH)2
B) K3PO4
C) BaSO4
D) CoCO3
E) PbCl2
21.Consider an aqueous solution of calcium nitrate added to an aqueous solution of sodium phosphate.
What is the formula of the solid formed in the reaction?
A) Ca(PO4)2
B) CaPO4
C) Ca3(PO4)2
D) Ca3(PO3)2
E) none of these
22.You mix 55 mL of 1.00 M silver nitrate with 25 mL of 0.84 M sodium chloride. What mass of silver
chloride should you form?
A) 3.0 g
B) 6.0 g
C) 3.3 g
D) 6.6
E) none of these
23.When solutions of carbonic acid and copper(II) hydroxide react, which of the following are spectator
ions?
A) hydrogen ion
B) carbonate ion
C) copper(II) ion
D) hydroxide ion
E) none of these
24.Sulfamic acid, HSO3NH2 (molar mass = 97.1 g/mol), is a strong monoprotic acid that can be used to
standardize a strong base:
A 0.165-g sample of HSO3NH2 required 19.4 mL of an aqueous solution of KOH for a complete
reaction. What is the molarity of the KOH solution?
A) 0.00170 M
B) 8.76 M
C) 0.0876 M
D) 0.0330 M
E) none of these
25.In the reaction 2Cs(s) + Cl2(g)  2CsCl(s), Cl2 is
A) the reducing agent
B) the oxidizing agent
C) oxidized
D) the electron donor
E) two of these
26.Which of the following are oxidation-reduction reactions?
I.
PCl3 + Cl2  PCl5
II.
Cu + 2AgNO3  Cu(NO3)2 + 2Ag
III.
CO2 + 2LiOH  Li2CO3 + H2O
IV.
FeCl2 + 2NaOH  Fe(OH)2 + 2NaCl
A)
B)
C)
D)
E)
III
IV
I and II
I, II, and III
I, II, III, and IV
27. Balance the following oxidation-reduction reaction using the oxidation number method:
Fe3+ + I–  Fe2+ + I2
In the balanced equation, the coefficient of Fe2+ is
A) 1
B) 2
C) 3
D) 4
E) none of these
27.The MnO4– is often used to analyze for the Fe2+ content of an aqueous solution via the reaction
MnO4–(aq) + Fe2+(aq) + H+(aq) Fe3+(aq) + Mn2+(aq) + H2O(l)
What is the ratio of Fe2+ : MnO4– in the balanced equation?
A) 1 : 1
B) 2 : 1
C) 3 : 1
D) 4 : 1
E) 5 : 1
28.Which of the following would represent the greatest pressure?
A) 0.680 atm
B) 517 mmHg
C) 11.4 psi
D) 62106 Pa
E) 14.1 in Hg
29.Gaseous chlorine is held in two separate containers at identical temperature and pressure. The volume
of container 1 is 1.30 L, and it contains 6.70 mol of the gas. The volume of container 2 is 2.33 L.
How many moles of the gas are in container 2?
A) 12.0 mol
B) 20.3 mol
C) 0.452 mol
D) 3.74 mol
E) none of these
29.A gas sample is heated from -20.0°C to 57.0°C and the volume is increased from 2.00 L to 4.50 L. If
the initial pressure is 0.140 atm, what is the final pressure?
A) 0.0477 atm
B) –0.177 atm
C) 0.411 atm
D) 0.242 atm
E) 0.0811 atm
30.A sample of gas is in a 50.0-mL container at a pressure of 645 torr and a temperature of 25°C. The
entire sample is heated to a temperature of 35°C and transferred to a new container whose
volume is 98.7 mL. The pressure of the gas in the second container is about:
A) 457 torr
B) 316 torr
C) 1.32  10 3 torr
D) 65 torr
E) 338 torr
31.The mass of 1.12 liters of gas Y at STP is found to be 6.23 g. The molar mass of gas Y is
A) 56.0 g/mol
B) 89.0 g/mol
C) 125 g/mol
D) 140. g/mol
E) 157 g/mol
32.It is found that 250. mL of a gas at STP has a mass of 0.700 g. What is the molar mass?
A) 62.7 g/mol
B) 2.80 g/mol
C) 15.9 g/mol
D) 11.2 g/mol
E) 128 g/mol
33.At 1000°C and 10. torr, the density of a certain element in the gaseous state is
element is:
. The
A)
B)
C)
D)
E)
F
He
Na
Zn
Hg
34.Oxygen gas, generated by the reaction
is collected over water at
27°C in a 1.55-L vessel at a total pressure of 1.00 atm. (The vapor pressure of H2O at 27°C is
26.0 torr.) How many moles of KClO3 were consumed in the reaction?
A) 0.0608 moles
B) 0.0912 moles
C) 0.0405 moles
D) 0.0434 moles
E) 1.50 moles
35.The partial pressures of CH4, N2, and O2 in a sample of gas were found to be 135
mmHg, 508 mmHg, and 571 mmHg, respectively. Calculate the mole fraction of nitrogen.
A)
B)
C)
D)
E)
20.4
0.470
0.418
0.751
0.359