The following pictures represent binary hydrides, AHx, where A = Na, Ti, C, or Cl. Lightly-shaded
spheres represent H atoms or ions and darkly-colored spheres represent atoms or ions of element A.
98) Which hydride has the lowest melting point?
A) hydride (1)
B) hydride (2)
C) hydride (3)
D) hydride (4)
99) Which hydride reacts with water at 25°C to give H2 gas and forms a basic solution?
A) hydride (1)
B) hydride (2)
C) hydride (3)
D) hydride (4)
100) Which hydride dissolves in water to form an acidic solution?
A) hydride (1)
B) hydride (2)
C) hydride (3)
D) hydride (4)
101) In the picture representing binary hydride AHx, lightly-shaded spheres represent H atoms or ions
and darkly-shaded spheres represent atoms or ions of the other element, A. If A is a second-period
element, the oxidation state of hydrogen and the oxidation state of element A in the binary hydride
shown below are
A) +1 and -3.
B) +1 and -1.
C) -1 and +1.
D) -1 and +3.
102) In the picture representing binary hydride AHx, lightly-shaded spheres represent H atoms or ions
and darkly-shaded spheres represent atoms or ions of the other element, A. The oxidation state of
hydrogen and the oxidation state of element A in the binary hydride shown below are
A) +1 and -3.
B) +1 and -1.
C) -1 and +1.
D) -1 and +3.
103) In the picture representing binary hydride AHx, lightly-shaded spheres represent H atoms or ions
and darkly-shaded spheres represent atoms or ions of the other element, A. If A is a second-period
element, the oxidation state of hydrogen and the oxidation state of element A in the binary hydride
shown below are
A) +1 and -2.
B) +1 and -1.
C) -1 and +1.
D) -1 and +3.
104) What group of elements is most likely to form covalent molecular hydrides?
A) A
B) B
C) C
D) D
105) What group of elements is most likely to from ionic hydrides of the type MH2?
A) A
B) B
C) C
D) D
106) Which element shown on the periodic table above forms a covalent binary hydride with the
formula MX3?
A) element A
B) element B
C) element C
D) element D
107) Which element shown on the periodic table above forms an ionic binary hydride with the formula
MX2?
A) element A
B) element B
C) element C
D) element D
108) Which element shown on the periodic table above forms a covalent binary hydride with the
formula MX4?
A) element A
B) element B
C) element C
D) element D
109) Which element shown on the periodic table above forms an interstitial binary hydride with the
formula MXx?
A) element A
B) element B
C) element C
D) element D
110) Picture (a) shows p-orbital overlap between carbon and oxygen atoms; picture (b) shows p-orbital
overlap between silicon and oxygen atoms.
Based on these pictures, it is expected that
A) carbon and oxygen form better σ bonds than silicon and oxygen, so C-O single bonds are stronger
than Si-O single bonds.
B) silicon and oxygen form better σ bonds than carbon and oxygen, so Si-O single bonds are stronger
than C-O single bonds.
C) carbon and oxygen form better π bonds than silicon and oxygen, so C=O double bonds are stronger
than Si=O double bonds.
D) silicon and oxygen form better π bonds than carbon and oxygen, so Si=O double bonds are stronger
than C=O double bonds.
111) In the following picture of an oxide, darkly-shaded spheres represent oxygen atoms or ions and
lightly-shaded spheres represent atoms or ions of a second-row element in its highest oxidation state.
Tell whether the oxide is covalent or ionic and whether the oxide is acidic or basic.
A) covalent and acidic
B) covalent and basic
C) ionic and acidic
D) ionic and basic
112) In the following picture of an oxide, darkly-shaded spheres represent oxygen atoms or ions and
lightly-shaded spheres represent atoms or ions of a third-row element in its highest oxidation state. Tell
whether the oxide is covalent or ionic and whether the oxide is acidic or basic.
A) covalent and acidic
B) covalent and basic
C) ionic and acidic
D) ionic and basic
113) In the following picture of an oxide, darkly-shaded spheres represent oxygen atoms or ions and
lightly-shaded spheres represent atoms or ions of a second-row element in its highest oxidation state.
Tell whether the oxide is covalent or ionic and whether the oxide is acidic or basic.
A) covalent and acidic
B) covalent and basic
C) ionic and acidic
D) ionic and basic
114) In the following picture of an oxide, darkly-shaded spheres represent oxygen atoms or ions and
lightly-shaded spheres represent atoms or ions of a second-row element in its highest oxidation state.
Tell whether the oxide is covalent or ionic and whether the oxide is expected to be a gas (or a liquid) or
a high-melting solid.
A) covalent and gas or liquid
B) covalent and high-melting solid
C) ionic and liquid or gas
D) ionic and high-melting solid
115) In the following picture of an oxide, darkly-shaded spheres represent oxygen atoms or ions and
lightly-shaded spheres represent atoms or ions of a second-row element in its highest oxidation state.
Identify the element represented by the lightly-shaded spheres.
A) C
B) N
C) S
D) Si
116) In the following picture of an uncharged oxide, darkly-shaded spheres represent oxygen atoms or
ions and lightly-shaded spheres represent atoms or ions of a second- or third-row element in its highest
oxidation state. Identify the element represented by the lightly-shaded spheres.
A) Al
B) C
C) N
D) S
117) In the following picture of an oxide, darkly-shaded spheres represent oxygen atoms or ions and
lightly-shaded spheres represent atoms or ions of a second-row element in its highest oxidation state.
Identify the element represented by the lightly-shaded spheres.
A) C
B) Mg
C) N
D) Na
Look at the location of elements A, B, C, and D in the following periodic table. Consider the oxides that
form when the elements A-D are in their highest oxidation states.
118) Which oxide is the most ionic?
A) A
B) B
C) C
D) D
119) Which oxide is the most covalent?
A) A
B) B
C) C
D) D
120) Which oxide is the most acidic?
A) A
B) B
C) C
D) D
121) Which oxide is the most basic?
A) A
B) B
C) C
D) D
122) Which oxide is a solid with an infinitely extended three-dimensional crystal structure?
A) A
B) B
C) C
D) D
123) Which oxide has the highest melting point?
A) A
B) B
C) C
D) D
124) Which oxide has the lowest melting point?
A) A
B) B
C) C
D) D
125) The oxide of which element, identified by letters A, B, C, and D in the following periodic table, is
most acidic in its highest oxidation state?
A) A
B) B
C) C
D) D
126) The oxide of which element, identified by letters A, B, C, and D in the following periodic table, is
most basic in its highest oxidation state?
A) A
B) B
C) C
D) D
127) Look at the location of elements A, B, C, and D in the following periodic table. The oxide of which
element in its highest oxidation state can react with both H+(aq) and OH–(aq)?
A) A
B) B
C) C
D) D
128) Look at the location of elements A, B, C, and D in the following periodic table. The oxide of which
element in its highest oxidation state is a liquid?
A) A
B) B
C) C
D) D
129) The following molecular orbital energy level diagram shows the energies and occupancies of the
MOs derived from the atomic 2p orbitals for an oxygen-containing binary compound of potassium. This
compound is a
A) peroxide having a stronger O-O bond than O2.
B) peroxide having a weaker O-O bond than O2.
C) superoxide having a stronger O-O bond than O2.
D) superoxide having a weaker O-O bond than O2.
130) The following molecular orbital energy level diagram shows the energies and occupancies of the
MOs derived from the atomic 2p orbitals for an oxygen-containing binary compound of potassium. This
compound is a
A) peroxide having a stronger O-O bond than O2.
B) peroxide having a weaker O-O bond than O2.
C) superoxide having a stronger O-O bond than O2.
D) superoxide having a weaker O-O bond than O2.
131) The following molecular orbital energy level diagram shows the energies and occupancies of the
MOs derived from the atomic 2p orbitals for an oxygen-containing binary compound of potassium. This
compound is a
A) peroxide that is attracted by magnetic fields.
B) peroxide that is repelled by magnetic fields.
C) superoxide that is attracted by magnetic fields.
D) superoxide that is repelled by magnetic fields.
132) The following molecular orbital energy level diagram shows the energies and occupancies of the
MOs derived from the atomic 2p orbitals for an oxygen-containing binary compound of potassium. This
compound is a
A) peroxide that is attracted by magnetic fields.
B) peroxide that is repelled by magnetic fields.
C) superoxide that is attracted by magnetic fields.
D) superoxide that is repelled by magnetic fields.
18.2 Algorithmic Questions
1) How many grams of H2 gas can be produced by the reaction of 54.0 grams of Al(s) with an excess of
dilute hydrochloric acid in the reaction shown below?
2 Al(s) + 6 HCl(aq) → 2 AlCl3(aq) + 3 H2(g)
A) 2.68 g
B) 4.04 g
C) 6.05 g
D) 12.1 g
2) How many grams of zinc metal are required to produce 2.00 liters of hydrogen gas at STP according
to the chemical equation shown below?
Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g)
A) 0. 171 g
B) 5.83 g
C) 11.7 g
D) 131 g
3) How many grams of calcium hydride are required to produce 4.56 L of hydrogen gas at 25.0°C and
0.975 atm pressure according to the chemical equation shown below?
CaH2(s) + 2 H2O(l) → Ca(OH)2(aq) + 2 H2(g)
A) 3.82 g
B) 7.64 g
C) 15.3 g
D) 45.6 g
4) How many liters of hydrogen gas can be generated by reacting 9.25 grams of barium hydride with
water at 20°C and 755 mm Hg pressure according to the chemical equation shown below?
BaH2(s) + 2 H2O(l) → Ba(OH)2(aq) + 2 H2(g)
A) 0. 219 L
B) 0. 799 L
C) 1.60 L
D) 3.21 L
5) How many grams of water are required to produce 5.50 L of hydrogen gas at 25.0°C and 755 mm Hg
pressure according to the chemical equation shown below?
BaH2(s) + 2 H2O(l) → Ba(OH)2(aq) + 2 H2(g)
A) 2.01 g
B) 4.02 g
C) 4.07 g
D) 8.04 g
6) How many liters of hydrogen gas are needed to produce 100.0 grams of water at 25.0°C and 1.00 atm
pressure according to the chemical equation shown below?
2 H2(g) + O2(g) → 2 H2O(l)
A) 67.9 L
B) 136 L
C) 203 L
D) 407 L
7) What is the total volume of the mixture of hydrogen gas and oxygen gas can be obtained from the
electrolysis of 110.0 grams of water at 25.0°C and 1.00 atm pressure according to the chemical equation
shown below?
2 H2O(l) → 2 H2(g) + O2(g)
A) 74.7 L
B) 149 L
C) 224 L
D) 447 L
8) How many mL of O2 gas at 25°C and 755 mm Hg pressure can be produced from the thermal
decomposition of 0. 300 grams of KClO3(s) according to the chemical equation shown below?
2 KClO3(s) → 2 KCl(s) + 3 O2(g)
A) 30.1 mL
B) 40.2 mL
C) 90.4 mL
D) 181 mL
9) How many grams of KCl(s) are produced from the thermal decomposition of KClO3(s) which
produces 50.0 mL of O2(g) at 25°C and 1.00 atm pressure according to the chemical equation shown
below?
2 KClO3(s) → 2 KCl(s) + 3 O2(g)
A) 0. 102 g
B) 0. 152 g
C) 0. 167 g
D) 0. 304 g
10) How many liters of oxygen gas can be produced at STP from the decomposition of 0.250 L of 3.00
M H2O2 in the reaction according to the chemical equation shown below?
A) 8.41 L
B) 11.2 L
C) 16.8 L
D) 33.6 L
11) What is the total volume of hydrogen gas and oxygen gas that can be produced from the thermal
decomposition of 0. 0425 grams of H2O2 at 700°C and 755 mm Hg according to the chemical equation
shown below?
H2O2(l) → H2(g) + O2(g)
A) 50.2 mL
B) 100 mL
C) 151 mL
D) 201 mL
12) How many liters of O2 gas at 25°C and 1.00 atm pressure are needed to react with 60.25 grams of
potassium hydride according to the chemical equation shown below?
2 KH(s) + O2(g) → H2O(l) + K2O(s)
A) 9.19 L
B) 18.4 L
C) 36.8 L
D) 73.5 L
13) How many milliliters of ozone gas at at 25.0°C and 1.00 atm pressure are needed to react with 45.00
mL of a 0. 400 M aqueous solution of KI according to the chemical equation shown below?
O3(g) + 2 I–(aq) + H2O(l) → O2(g) + I2(s) + 2 OH–(aq)
A) 220. mL
B) 441 mL
C) 661 mL
D) 881 mL
14) Water accounts for approximately two-thirds of the mass of the adult human body. If an adult human
has a mass of 145 pounds, how many water molecules are there in the adult human’s body?
A) 96.7 molecules
B) 2.43 × 103 molecules
C) 1.47 × 1027 molecules
D) 2.20 × 1027 molecules
15) When 1.800 grams of anhydrous magnesium chloride were exposed to moist air, water was
absorbed by the sample. If the resulting hydrated compound has a mass of 2.481 grams, what is the
chemical formula of the hydrate?
A) MgCl2∙ H2O
B) MgCl2∙ 2H2O
C) MgCl2∙ 3H2O
D) MgCl2∙ 4H2O
16) A 0.954-gram sample of hydrated magnesium sulfate, MgSO4∙ xH2O, is heated until all of the
water is driven off. If 0.465 grams of anhydrous MgSO4 is obtained, how many water molecules
combine with each formula unit of magnesium sulfate in the hydrate?
A) 5
B) 6
C) 7
D) 8
17) When 0.350 grams of anhydrous copper(II) sulfate is exposed to moist air, it absorbs water. If the
hydrated copper compound has a mass of 0.508 grams, what is the chemical formula of the hydrate?
A) CuSO4∙ 2H2O
B) CuSO4∙ 3H2O
C) CuSO4∙ 4H2O
D) CuSO4∙ 5H2O
18.3 Short Answer Questions
1) Hydrogen has three isotopes,
1H
1
,
2H
1
, and
3H
1
, which are called ________, ________, and
________, respectively.
2) An example of an isotope effect is the difference in the dissociation of D2O compared to H2O, as
shown below.
H2O(l) ⇌ H+(aq) + OH–(aq) K =1.0 × 10-14
D2O(l) ⇌ D+(aq) + OD–(aq) K =2.0 × 10-15
A neutral H2O solution has a pH = ________, whereas a neutral D2O solution has a pH = pD =
________.
3) An example of an isotope effect is the difference in the dissociation of D2O compared to H2O, as
shown below.
H2O(l) ⇌ H+(aq) + OH–(aq) K =1.0 × 10-14
T2O(l) ⇌ T+(aq) + OT–(aq) K =6.0 × 10-16
A neutral H2O solution has a pH = ________, whereas a neutral T2O solution has a pH = pD =
________.
4) At 25°C the dissociation constant Kw for D2O is 0.195 × 10-14. What is the molar concentration of
OD– in 0.025 M DCl?
5) At 25°C the dissociation constant Kw for T2O is 0.06 × 10-14. What is the molar concentration of
OT– in 0.025 M TCl?
6) The first step in the steam-hydrocarbon re-forming process for the industrial preparation of hydrogen
is shown below.
H2O(g) + CH4(g) CO(g) + 3 H2(g)
In this reaction the atom that is oxidized is ________, which undergoes an oxidation number change
from ________ to ________.
7) Binary hydrides can be classified as covalent, ionic, or metallic. NaH, HCl, and NH3 are classified as
________, ________, and ________ binary hydrides, respectively.
8) Sodium hydride, NaH, reacts with water as shown in the equation below.
NaH(s) + H2O(l) → H2(g) + Na+(aq) + OH–(aq)
In this reaction the oxidation number of hydrogen in NaH, H2O, H2, and OH– is ________, ________,
________, and ________, respectively.
9) The strongest force that must be overcome in order to melt LiH, SiH4, H2S, and HF is ________,
________, ________, and ________, respectively.
10) Of LiH, SiH4, H2S, and HF, the binary hydrides expected to have the lowest and highest melting
points are ________ and ________, respectively.
11) An element that forms a basic oxide tends to form a hydride that is ________ (covalent, ionic).
12) An element that forms a covalent hydride tends to form an oxide that is ________ (acidic, basic).
13) A reaction occurs when 0.2105 g of CaH2 is dissolved in enough water to make 250 mL of solution.
This solution will have a pH = ________.
14) A reaction occurs when 0.2105 g of CaH2 is dissolved in enough water to make 250 mL of solution
will generate ________ liters of hydrogen gas at 0.972 atm and 21°C
15) The preparation of oxygen by the thermal decomposition of potassium chlorate is shown below.
2 KClO3(s) 2 KCl(s) + 3 O2(g)
In this reaction the atom that is reduced is ________, which undergoes an oxidation number change
from ________ to ________.
16) The direct methanol fuel cell (DMFC), a galvanic cell proposed for use in consumer products,
employs the overall reaction shown below. How many liters of oxygen at 25°C and 1.00 atm are
required to completely react with 0.641 g of CH3OH?
2 CH3OH(aq) + 3 O2(g) → 2 CO2(g) + 4 H2O(l)
17) The carbon atom in CO2 is π-bonded to two oxygen atoms. The silicon atom in SiO2 is ________-
bonded to ________ oxygen atoms.
18) Binary oxides can be classified as acidic, amphoteric, or basic. MgO, Al2O3, and SO3 are classified
as ________, ________, and ________ oxides, respectively.
19) Of Na2O, SO2, and SO3, equimolar aqueous solutions of ________ would be most acidic and of
________ would be most basic.
20) The high-temperature superconductor, YBa2Cu3O7 can be prepared by the reaction shown below.
2 Y2O3 + 8 BaO + 12 CuO + O2 → 4 YBa2Cu3O7
How many liters of oxygen at 800°C and 1.00 atm are required to completely react with 452 g of Y2O3?
21) Superoxide ion, O2–, peroxide ion, O22-, and oxide ion, O2-, contain ________, ________, and
________ unpaired electrons, respectively.
22) Of O2, O2–, and O22-, the oxygen-oxygen bond length is expected to be longest in ________ and
shortest in ________.
23) Hydrogen peroxide can act as an oxidizing agent or a reducing agent. The reaction of hydrogen
peroxide with permanganate ion in acidic solution is shown below.
H2O2(aq) + 2 MnO4–(aq) + 6 H+ → 5 O2(g) + 2 Mn2+(aq) + 8 H2O(l)
In this reaction hydrogen peroxide acts as the ________ agent, and the ________ atom undergoes a
change in oxidation number from ________ to ________.
24) The oxygen-oxygen bond order in ozone, O3, is ________. The oxygen-oxygen bond in O3 is
________ than the oxygen-oxygen bond in O2, so O3 is ________ reactive than O2.
25) Gas hydrates are solids in which a gas is encased in a polyhedral cage formed of water molecules.
One gas hydrate structure has the general formula Gx(H2O)46. Xenon forms a gas hydrate having the
composition 55.90% Xe, 4.93% H, and 39.17% O. What is the value of x in the xenon gas hydrate
Xex(H2O)46?
26) Anhydrous magnesium sulfate can be used as a drying agent to remove moisture from the
atmosphere. If the only product of this reaction is magnesium sulfate heptahydrate, how many grams of
water can be removed by 0.500 kg of magnesium sulfate?