Transcript
Chemistry The Molecular Nature of Matter and Change
The Components of Matter
1.
Kaolinite, a clay mineral with the formula Al4Si4O10(OH)8, is used as a filler in slick-paper for magazines and as a raw material for ceramics. Analysis shows that 14.35 g of kaolinite contains 8.009 g of oxygen. Calculate the mass percent of oxygen in kaolinite.
A)
1.792 mass %
D)
34.12 mass %
B)
24.80 mass %
E)
55.81 mass %
C)
30.81 mass %
Ans: E
2.
Compound 1 has a composition of 46.7 mass % of element A and 53.3 mass % of element B. A and B also form a second binary compound (compound 2). If the compositions of the two compounds are consistent with the law of multiple proportions, which of the following compositions could be that of compound 2?
A)
23.4 mass % A 76.6 mass % B
D)
53.3 mass % A 46.7 mass % B
B)
30.4 mass % A 69.6 mass % B
E)
73.3 mass % A 26.7 mass % B
C)
33.3 mass % A 66.7 mass % B
Ans: B
3.
What are the approximate carbon:hydrogen mass ratios in methane (CH4) and ethyne (C2H2)?
A)
1:4 and 1:1
D)
3:2 and 12:1
B)
3:2 and 6:1
E)
3:1 and 6:1
C)
3:1 and 12:1
Ans: C
4.
J. J. Thomson studied cathode ray particles (electrons) and was able to measure the mass/charge ratio. His results showed that
A)
the mass/charge ratio varied with as the cathode material was changed.
B)
the charge was always a whole-number multiple of some minimum charge.
C)
matter included particles much smaller than the atom.
D)
atoms contained dense areas of positive charge.
E)
atoms are largely empty space.
Ans: C
5.
Who is credited with measuring the mass/charge ratio of the electron?
A) Dalton B) Gay-Lussac C) Thomson D) Millikan E) Rutherford
Ans: C
6.
Who is credited with first measuring the charge of the electron?
A) Dalton B) Gay-Lussac C) Thomson D) Millikan E) Rutherford
Ans: D
7.
Millikan's oil-drop experiment
A)
established the charge on an electron.
B)
showed that all oil drops carried the same charge.
C)
provided support for the nuclear model of the atom.
D)
suggested that some oil drops carried fractional numbers of electrons.
E)
suggested the presence of a neutral particle in the atom.
Ans: A
8.
In a Millikan oil-drop experiment, the charges on several different oil drops were as follows: –5.92; –4.44; –2.96; –8.88. The units are arbitrary. What is the likely value of the electronic charge in these arbitrary units?
A) –1.11 B) –1.48 C) –2.22 D) –2.96 E) –5.55
Ans: B
9.
Who is credited with discovering the atomic nucleus?
A) Dalton B) Gay-Lussac C) Thomson D) Millikan E) Rutherford
Ans: E
10.
Rutherford bombarded gold foil with alpha (?) particles and found that a small percentage of the particles were deflected. Which of the following was not accounted for by the model he proposed for the structure of atoms?
A)
the small size of the nucleus
B)
the charge on the nucleus
C)
the total mass of the atom
D)
the existence of protons
E)
the presence of electrons outside the nucleus
Ans: C
11.
Which one of the following statements about atoms and subatomic particles is correct?
A)
Rutherford discovered the atomic nucleus by bombarding gold foil with electrons.
B)
The proton and the neutron have identical masses.
C)
The neutron's mass is equal to that of a proton plus an electron.
D)
A neutral atom contains equal numbers of protons and electrons.
E)
An atomic nucleus contains equal numbers of protons and neutrons.
Ans: D
12.
The chemical symbol for potassium is
A) P. B) Po. C) Pt. D) Pm. E) K.
Ans: E
13.
Which of the following symbols does not represent an element?
A) O2 B) Co C) HF D) Cs E) Xe
Ans: C
14.
When an atom is represented by the symbol , the value of A is the
A)
number of neutrons in the atom.
B)
number of protons in the atom.
C)
atomic mass of the element.
D)
total number of electrons and neutrons in the atom.
E)
total number of protons and neutrons in the atom.
Ans: E
15.
An isotope of which of the following elements is chosen as a standard in measuring atomic mass?
A) carbon B) oxygen C) hydrogen D) neon E) helium
Ans: A
16.
One amu is defined as
A)
the mass of a proton.
D)
1/20 the mass of an atom of .
B)
1/12 the mass of an atom of .
E)
1/16 the mass of an atom of .
C)
the mass of an atom of .
Ans: B
17.
Bromine is the only nonmetal that is a liquid at room temperature. Consider the isotope bromine-81, . Select the combination which lists the correct atomic number, neutron number, and mass number, respectively.
A) 35, 46, 81
B) 35, 81, 46
C) 81, 46, 35
D) 46, 81, 35
E) 35, 81, 116
Ans: A
18.
Atoms X, Y, Z, and R have the following nuclear compositions:
Which two are isotopes?
A) X & Y B) X & R C) Y & R D) Z & R E) X & Z
Ans: E
19.
Lithium forms compounds which are used in dry cells and storage batteries and in high-temperature lubricants. It has two naturally occurring isotopes, 6Li (isotopic mass = 6.015121 amu) and 7Li (isotopic mass = 7.016003 amu). Lithium has an atomic mass of 6.9409 amu. What is the percent abundance of lithium-6?
A) 92.50% B) 86.66% C) 46.16% D) 7.503% E) 6.080%
Ans: D Difficulty: H
20.
Silicon, which makes up about 25% of Earth's crust by mass, is used widely in the modern electronics industry. It has three naturally occurring isotopes, 28Si, 29Si, and 30Si. Calculate the atomic mass of silicon.
Isotope
Isotopic Mass (amu)
Abundance %
28Si
27.976927
92.23
29Si
28.976495
4.67
30Si
29.973770
3.10
A)
29.2252 amu
D)
28.0855 amu
B)
28.9757 amu
E)
27.9801 amu
C)
28.7260 amu
Ans: D
21.
Bromine has two naturally-occurring isotopes. 79Br has a mass of 78.9 amu and accounts for 50.3% of bromine atoms. If the atomic mass of bromine is 79.9 amu, what is the mass of an atom of the second bromine isotope?
A) 77.9 amu B) 80.0 amu C) 80.1 amu D) 80.9 amu E) 88.9 amu
Ans: D
22.
In the modern periodic table, the order in which the elements are placed is based on
A)
atomic mass.
D)
atomic size.
B)
mass number.
E)
chemical reactivity.
C)
atomic number.
Ans: C
23.
Which of the following elements are the least reactive?
A)
alkali metals
D)
alkaline earth metals
B)
noble gases
E)
metalloids
C)
halogens
Ans: B
24.
Which of the following is a non-metal?
A)
lithium, Li, Z = 3
D)
bismuth, Bi, Z = 83
B)
bromine, Br, Z = 35
E)
sodium, Na, Z = 11
C)
mercury, Hg, Z = 80
Ans: B
25.
Which of the following is a metal?
A)
nitrogen, N, Z = 7
D)
thallium, Tl, Z = 81
B)
phosphorus, P, Z = 15
E)
silicon, Si, Z = 14
C)
arsenic, Z = 33
Ans: D
26.
Which of the following is a metalloid?
A)
carbon, C, Z = 6
D)
iridium, Z = 77
B)
sulfur, S, Z = 16
E)
bromine, Br, Z = 35
C)
germanium, Ge, Z = 32
Ans: C
27.
Which one of the following groups does not contain any metals?
A)
C, S, As, H
D)
Xe, Hg, Ge, O
B)
Cu, P, Se, Kr
E)
Cl, Al, Si, Ar
C)
N, Ne, Nd, Np
Ans: A
28.
A column of the periodic table is called a
A) group. B) period. C) isotopic mixture. D) pillar. E) shell.
Ans: A
29.
A row of the periodic table is called a
A) group. B) period. C) isotopic mixture. D) family. E) subshell.
Ans: B
30.
What is the chemical symbol for the group 6A (16) element that lies in period 4?
A) Cr B) Hf C) W D) Ti E) Se
Ans: E
31.
Which of the following compounds is ionic?
A) PF3 B) CS2 C) HCl D) SO2 E) MgCl2
Ans: E
32.
After an atom has lost an electron it becomes a/an ______ and has a _______ charge.
A)
anion, positive
D)
cation, positive
B)
isotope, negative
E)
nucleus, positive
C)
anion, negative
Ans: D
33.
Which of the following ions occurs commonly?
A) N3+ B) S6+ C) O2– D) Ca+ E) Cl+
Ans: C
34.
Which of the following ions occurs commonly?
A) P3+ B) Br7+ C) O6+ D) Ca2+ E) K–
Ans: D
35.
Which of the following compounds is covalent?
A) CaCl2 B) MgO C) Al2O3 D) Cs2S E) PCl3
Ans: E
36.
Select the incorrect statement about elements and compounds.
A)
All ionic compounds are neutral.
B)
Some elements exist as molecules.
C)
The bonding in compounds may be covalent or ionic.
D)
The molecular formula of a compound provides more information than the structural formula.
E)
Among the elements, there are more metals than non-metals.
Ans: D
37.
Which, if any, of the following elements do not occur in the major classes of organic compounds?
A)
H
B)
C
C)
N
D)
O
E)
All the above elements occur in the major classes of organic compounds.
Ans: E
38.
Which of the following is the empirical formula for hexane, C6H14?
A) C12H28 B) C6H14 C) C3H7 D) CH2.3 E) C0.43H
Ans: C
39.
Sodium oxide combines violently with water. Which of the following gives the formula and the bonding for sodium oxide?
A)
NaO, ionic compound
D)
Na2O, covalent compound
B)
NaO, covalent compound
E)
Na2O2, ionic compound
C)
Na2O, ionic compound
Ans: C
40.
Barium fluoride is used in embalming and in glass manufacturing. Which of the following gives the formula and bonding for barium fluoride?
A)
BaF2, ionic compound
D)
BaF, covalent compound
B)
BaF2, covalent compound
E)
Ba2F, ionic compound
C)
BaF, ionic compound
Ans: A
41.
The colorless substance, MgF2, is used in the ceramics and glass industry. What is its name?
A)
magnesium difluoride
B)
magnesium fluoride
C)
magnesium(II) fluoride
D)
monomagnesium difluoride
E)
none of the above, since they are all misspelled
Ans: B
42.
The compound, BaO, absorbs water and carbon dioxide readily and is used to dry gases and organic solvents. What is its name?
A)
barium oxide
D)
baric oxide
B)
barium(II) oxide
E)
barium peroxide
C)
barium monoxide
Ans: A
43.
What is the name of Na2O?
A)
disodium monoxide
D)
sodium(I) oxide
B)
sodium monoxide
E)
sodium oxide
C)
sodium dioxide
Ans: E
44.
The substance, CaSe, is used in materials which are electron emitters. What is its name?
A)
calcium monoselenide
D)
calcium(I) selenide
B)
calcium(II) selenide
E)
calcium(II) selenium
C)
calcium selenide
Ans: C
45.
The substance, CoCl2, is useful as a humidity indicator because it changes from pale blue to pink as it gains water from moist air. What is its name?
A)
cobalt dichloride
D)
cobaltic chloride
B)
cobalt(II) chloride
E)
copper(II) chloride
C)
cobalt chloride
Ans: B
46.
In the ionic compound with the general formula M2X3, the likely charge on X is
A) +1. B) +3. C) –1. D) –2. E) –3.
Ans: D
47.
Which one of the following combinations of names and formulas of ions is incorrect?
A)
O2– oxide
D)
PO43– phosphate
B)
Al3+ aluminum
E)
CrO42– chromate
C)
NO3– nitrate
Ans: A Difficulty: H
48.
Which one of the following is a polyatomic cation?
A) nitrate
B) chromate
C) permanganate
D) hydronium
E) potassium
Ans: D
49.
Which one of the following combinations of names and formulas of ions is incorrect?
A)
O2– oxide
D)
HCO3– hydrogen carbonate
B)
Cd2+ cadmium
E)
NO2– nitrate
C)
ClO3– chlorate
Ans: E Difficulty: H
50.
Which one of the following combinations of names and formulas of ions is incorrect?
A)
Ba2+ barium
D)
ClO4– perchlorate
B)
S2– sulfate
E)
HCO3– bicarbonate
C)
CN– cyanide
Ans: B
51.
Which one of the following combinations of names and formulas of ions is incorrect?
A)
NH4+ ammonium
D)
S2O32– thiosulfate
B)
S2– sulfide
E)
ClO3– perchlorate
C)
CN– cyanide
Ans: E Difficulty: H
52.
A red glaze on porcelain can be produced by using MnSO4. What is its name?
A)
manganese disulfate
D)
manganese sulfate
B)
manganese(II) sulfate
E)
manganese(I) sulfate
C)
manganese(IV) sulfate
Ans: B
53.
The compound, (NH4)2S, can be used in analysis for trace amounts of metals present in a sample. What is its name?
A)
ammonium sulfide
D)
ammonia(I) sulfite
B)
diammonium sulfide
E)
ammonium(I) sulfide
C)
ammonium sulfite
Ans: A
54.
The substance, KClO3, is a strong oxidizer used in explosives, fireworks, and matches. What is its name?
A)
potassium chlorite
D)
potassium(I) chlorate
B)
potassium chloride
E)
potassium chlorate
C)
potassium(I) chlorite
Ans: E
55.
The compound, NaH2PO4, is present in many baking powders. What is its name?
A)
sodium biphosphate
D)
sodium hydrophosphate
B)
sodium hydrogen phosphate
E)
sodium dihydride phosphate
C)
sodium dihydrogen phosphate
Ans: C
56.
Zinc acetate is used in preserving wood and in manufacturing glazes for porcelain. What is its formula?
A)
ZnAc2
D)
Zn2CH3COO
B)
ZnCH3COO
E)
ZnCH3COCH3
C)
Zn(CH3COO)2
Ans: C
57.
Silver chloride is used in photographic emulsions. What is its formula?
A) Ag2Cl3 B) Ag2Cl C) AgCl3 D) AgCl2 E) AgCl
Ans: E
58.
Barium sulfate is used in manufacturing photographic paper. What is its formula?
A) BaSO4 B) Ba(SO4)2 C) Ba2SO4 D) Ba2(SO4)3 E) BaSO3
Ans: A
59.
Sodium peroxide is an oxidizer used to bleach animal and vegetable fibers. What is its formula?
A) NaO B) NaO2 C) Na2O2 D) Na2O E) NaH2O2
Ans: C
60.
What is the formula for magnesium sulfide?
A) MgS B) MgS2 C) Mg2S D) Mg2S3 E) MgSO4
Ans: A
61.
Ferric oxide is used as a pigment in metal polishing. Which of the following is its formula?
A) FeO B) Fe2O C) FeO3 D) Fe2O5 E) Fe2O3
Ans: E
62.
What is the formula for lead (II) oxide?
A) PbO B) PbO2 C) Pb2O D) PbO4 E) Pb2O3
Ans: A
63.
Potassium permanganate is a strong oxidizer that reacts explosively with easily oxidized materials. What is its formula?
A) KMnO3 B) KMnO4 C) K2MnO4 D) K(MnO4)2 E) K2Mn2O7
Ans: B
64.
Calcium hydroxide is used in mortar, plaster, and cement. What is its formula?
A) CaOH B) CaOH2 C) Ca2OH D) Ca(OH)2 E) CaHO2
Ans: D
65.
What is the formula for lithium nitrite?
A) LiNO2 B) Li2NO2 C) LiNO3 D) Li2NO3 E) LiNO4
Ans: A
66.
Iron (III) chloride hexahydrate is used as a coagulant for sewage and industrial wastes. What is its formula?
A)
Fe(Cl?6H2O)3
D)
Fe3Cl(H2O)6
B)
Fe3Cl?6H2O
E)
FeCl3?6H2O
C)
FeCl3(H2O)6
Ans: E
67.
Which one of the following formulas of ionic compounds is the least likely to be correct?
A) NH4Cl B) Ba(OH)2 C) Na2SO4 D) Ca2NO3 E) Cu(CN)2
Ans: D
68.
Which one of the following formulas of ionic compounds is the least likely to be correct?
A) CaCl2 B) NaSO4 C) MgCO3 D) KF E) Cu(NO3)2
Ans: B
69.
What is the name of the acid formed when H2S gas is dissolved in water?
A)
sulfuric acid
D)
hydrosulfurous acid
B)
sulfurous acid
E)
sulfidic acid
C)
hydrosulfuric acid
Ans: C Difficulty: H
70.
What is the name of the acid formed when HBr gas is dissolved in water?
A)
bromic acid
D)
hydrobromous acid
B)
bromous acid
E)
hydrobromidic acid
C)
hydrobromic acid
Ans: C
71.
What is the name of the acid formed when HClO4 liquid is dissolved in water?
A)
hydrochloric acid
D)
chlorous acid
B)
perchloric acid
E)
hydrochlorate acid
C)
chloric acid
Ans: B
72.
What is the name of the acid formed when HCN gas is dissolved in water?
A)
cyanic acid
D)
hydrocyanous acid
B)
hydrocyanic acid
E)
hydrogen cyanide
C)
cyanous acid
Ans: B
73.
The name for HF(g) is
A)
hydrofluoric acid.
D)
hydrogen fluorine.
B)
hydrogen(I) fluoride.
E)
fluoric acid.
C)
hydrogen fluoride.
Ans: C
74.
Which one of the following combinations of names and formulas is incorrect?
A)
H3PO4 phosphoric acid
D)
H2CO3 carbonic acid
B)
HNO3 nitric acid
E)
KOH potassium hydroxide
C)
NaHCO3 sodium carbonate
Ans: C
75.
What is the name of PCl3?
A)
phosphorus chloride
D)
trichlorophosphide
B)
phosphoric chloride
E)
phosphorus trichloride
C)
phosphorus trichlorate
Ans: E
76.
The compound, P4S10, is used in the manufacture of safety matches. What is its name?
A)
phosphorus sulfide
D)
tetraphosphorus decasulfide
B)
phosphoric sulfide
E)
phosphorus pentasulfide
C)
phosphorus decasulfide
Ans: D
77.
What is the name of BBr3?
A)
boron bromide
D)
tribromoboride
B)
boric bromide
E)
bromine triboride
C)
boron tribromide
Ans: C
78.
What is the name of IF7?
A)
iodine fluoride
D)
heptafluoroiodide
B)
iodic fluoride
E)
heptafluorine iodide
C)
iodine heptafluoride
Ans: C
79.
What is the name of P4Se3?
A)
phosphorus selenide
D)
phosphoric selenide
B)
phosphorus triselenide
E)
tetraphosphorus triselenide
C)
tetraphosphorus selenide
Ans: E
80.
Diiodine pentaoxide is used as an oxidizing agent that converts carbon monoxide to carbon dioxide. What is its chemical formula?
A) I2O5 B) IO5 C) 2IO5 D) I5O2 E) (IO5)2
Ans: A
81.
Tetrasulfur dinitride decomposes explosively when heated. What is its formula?
A) S2N4 B) S4N2 C) 4SN2 D) S4N E) S2N
Ans: B
82.
Chlorine dioxide is a strong oxidizer that is used for bleaching flour and textiles and for purification of water. What is its formula?
A) (ClO)2 B) Cl2O C) Cl2O2 D) Cl2O4 E) ClO2
Ans: E
83.
The formula of heptane is
A) C6H12. B) C6H14. C) C7H14. D) C7H16. E) C8H16.
Ans: D
84.
Ammonium sulfate, (NH4)2SO4, is a fertilizer widely used as a source of nitrogen. Calculate its molecular mass.
A)
63.07 amu
D)
128.11 amu
B)
114.10 amu
E)
132.13 amu
C)
118.13 amu
Ans: E
85.
Sodium chromate is used to protect iron from corrosion and rusting. Determine its molecular mass.
A)
261.97 amu
D)
138.98 amu
B)
238.98 amu
E)
74.99 amu
C)
161.97 amu
Ans: C
86.
Iodine pentafluoride reacts slowly with glass and violently with water. Determine its molecular mass.
A)
653.52 amu
D)
202.90 amu
B)
259.89 amu
E)
145.90 amu
C)
221.90 amu
Ans: C
87.
Determine the molecular mass of iron (III) bromide hexahydrate, a substance used as a catalyst in organic reactions.
A)
403.65 amu
D)
313.57 amu
B)
355.54 amu
E)
295.56 amu
C)
317.61 amu
Ans: A
88.
Name the three important “laws” that were accounted for by Dalton's atomic theory.
Ans:
laws of conservation of mass; definite composition; multiple proportions
89.
Dalton's atomic theory has required some modifications in the light of subsequent discoveries. For any three appropriate postulates of Dalton's atomic theory
a. state the postulate in its original form.
b. in one sentence, describe why the postulate has needed modification.
Ans:
1. Matter consists of atoms which are indivisible, cannot be created or destroyed. But, atoms are divisible, as the existence of subatomic particles shows.
2. Atoms of one element cannot be converted into atoms of another element. They can be converted in various nuclear reactions, including radioactive decay.
3. Atoms of an element are identical in mass and other properties. Isotopes of an element differ in their masses and other properties.
90.
Fill in the blank spaces and write out all the symbols in the left hand column in full, in the form (i.e., include the appropriate values of Z and A as well as the correct symbol X).
Symbol
# protons
# neutrons
# electrons
…
17
18
…
Au
…
118
…
…
…
20
20
Ans:
Symbol
# protons
# neutrons
# electrons
17
18
17
79
118
79
20
20
20
91.
The following charges on individual oil droplets were obtained during an experiment similar to Millikan's. Use them to determine a charge for the electron in coulombs (C), showing all your working.
Charges (C): –3.184 × 10–19; –4.776 × 10–19; –7.960 × 10–19
Ans:
–1.59 × 10–19 C
92.
State the two important experimental results (and the names of the responsible scientists) which enabled the mass of the electron to be determined.
Ans:
Thomson measured m/e, the mass-to-charge ratio. Millikan measured e, the charge. Thus, the mass m could be calculated.
93.
For each of the following elements, indicate whether it is a metal, a non-metal, or a metalloid:
a. S
b. Ge
c. g
d. H
e. I
f. Si
Ans:
a. nonmetal
b. metalloid
c. metal
d. nonmetal
e. nonmetal
f. metalloid
94.
Give the common name of the group in the periodic table to which each of the following elements belongs:
a. Rb
b. Br
c. Ba
d. Ar
Ans:
a. alkali metals
b. halogens
c. alkaline earth metals
d. noble gases
95.
a. Give the names of the following ions:
(i) NH4+
(ii) SO32–
b. Write down the formulas of the following ions:
(i) aluminum
(ii) carbonate
Ans:
a. (i) ammonium
(ii) sulfite
b. (i) Al3+
(ii) CO32–
96.
a. Give the names of the following ions:
(i) O22–
(ii) SO42–
b. Write down the formulas of the following ions:
(i) ammonium
(ii) nitrate
Ans:
a. (i) peroxide
(ii) sulfate
b. (i) NH4+
(ii) NO3–
97.
For each of the following names, write down the corresponding formula, including charge where appropriate (atomic numbers and mass numbers are not required):
a. zinc ion
b. nitrite ion
c. carbonic acid
d. cyanide ion
Ans:
a. Zn2+
b. NO2–
c. H2CO3
d. CN–
98.
Calculate the molecular masses of the following:
a. Cl2
b. H2O2
c. (NH4)2SO4
d. Ba(NO3)2
Ans:
a. 70.90 amu
b. 34.02 amu
c. 132.2 amu
d. 261.3 amu
99.
In nature, some elements exist as molecules, while others do not.
Ans: True
100.
Modern studies have shown that the Law of Multiple Proportions is not valid.
Ans: False
101.
Atoms of one element cannot be converted to another element by any known method.
Ans: False
102.
The mass of a neutron is equal to the mass of a proton plus the mass of an electron.
Ans: False
103.
All neutral atoms of tin have 50 protons and 50 electrons.
Ans: True
104.
Copper (Cu) is a transition metal.
Ans: True
105.
Lead (Pb) is a main-group element.
Ans: True
106.
Ionic compounds may carry a net positive or negative charge.
Ans: False
107.
When an alkali metal combines with a non-metal, a covalent bond is normally formed.
Ans: False
108.
The molecular formula of a compound provides more information than its structural formula.
Ans: False
109.
The formula C9H20 is an empirical formula.
Ans: True
