Chemistry The Science in Context

Thomas R. Gilbert

Chapter 2

Atoms, lons, and Molecules: Matter Starts Here - all with Video Answers

Educators

+ 2 more educators

Chapter Questions

Problem 1

Alpha and beta particles emitted by a sample of pitchblende escape through a narrow channel in the shielding surrounding the sample and into an electrical field as shown in Figure P2.1. Which path in the figure corresponds to each form of radiation?
(FIGURE CAN'T COPY)

Amy Jiang

Amy Jiang

Numerade Educator

Problem 2

Does the radiation that follows the red path in Figure P2.1 penetrate solid objects better than the radiation following the green path? Explain your answer.
(FIGURE CAN'T COPY)

Amy Jiang

Numerade Educator

Problem 3

In Figure $\mathrm{P} 2.3$ the blue spheres represent nitrogen atoms and the red spheres represent oxygen atoms. The figure as a whole represents which of the following gases? (a) $\mathrm{N}_{2} \mathrm{O}_{3}$
(b) $\mathrm{N}_{7} \mathrm{O}_{11} ;$ (c) a mixture of $\mathrm{NO}_{2}$ and $\mathrm{NO} ;$ (d) a mixture of
$\mathrm{N}_{2}$ and $\mathrm{O}_{3}$
(FIGURE CAN'T COPY)

Amy Jiang

Numerade Educator

Problem 4

In Figure $P 2.4$ the black spheres represent carbon atoms and the red spheres represent oxygen atoms. Which of the following statements about the two equal-volume compartments is or are true?(FIGURE CAN'T COPY)
a. The compartment on the left contains $\mathrm{CO}_{2} ;$ the one on the right contains CO.
b. The compartments contain the same mass of carbon.
c. The ratio of oxygen to carbon in the gas in the left compartment is twice that of the gas in the right compartment.
d. The pressures inside the two compartments are equal. (Assume that the pressure of a gas is proportional to the number of particles in a given volume.)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 5

Which of the highlighted elements in Figure $\mathrm{P} 2.5$ is
(a) a reactive nonmetal, (b) a chemically inert gas,
(c) a reactive metal?
(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 6

Which of the highlighted elements in Figure P2.6 forms monatomic ions with a charge of (a) $1+,(\mathrm{b}) 2+,(\mathrm{c}) 3+$
(d) $1-,$ (e) $2-?$
(FIGURE CAN'T COPY)

Amy Jiang

Numerade Educator

Problem 7

Which of the highlighted elements in Figure $P 2.7$ forms an oxide with the following formula: (a) $\mathrm{XO} ;$ (b) $\mathrm{X}_{2} \mathrm{O}$
(c) $\mathrm{XO}_{2} ;$ (d) $\mathrm{X}_{2} \mathrm{O}_{3} ?$
(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 8

Which of the highlighted elements in Figure $\mathrm{P} 2.8$ forms an oxoanion with the following generic formula: (a) $\mathrm{XO}_{4}^{-}$
(b) $\mathrm{XO}_{4}^{2-} ;$ (c) $\mathrm{XO}_{4}^{3-} ;$ (d) $\mathrm{XO}_{3}^{-} ?$
(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 9

Which of the highlighted elements in Figure $\mathrm{P} 2.9$ is not formed by the fusion of lighter elements in the cores of giant stars?
(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 10

Use representations [A] through [I] in Figure P2.10 to answer questions a-f.
a. Which are covalent compounds?
b. Which are ionic compounds?
c. Which incorporates both covalent and ionic bonding?
d. Which two representations demonstrate the law of multiple proportions?
e. Which, if any, of the representations have the same empirical formula?
f. What are the names of the substances in $[\mathrm{D}],[\mathrm{F}]$ and $[\mathrm{H}]$ ?.
(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 11

Explain how the results of the gold-foil experiment led Rutherford to dismiss the plum-pudding model of the atom and create his own model based on a nucleus surrounded by electrons.

Amy Jiang

Numerade Educator

Problem 12

Had the plum-pudding model been valid, how would the results of the gold-foil experiment have differed from what Geiger and Marsden actually observed?

Amy Jiang

Numerade Educator

Problem 13

What properties of cathode rays led Thomson to conclude that they were not pure energy, but rather particles with an electric charge?

Amy Jiang

Numerade Educator

Problem 14

What would be observed if the charges on the plates of Millikan's apparatus (Figure 2.4 ) were reversed?

Ronald Prasad

Numerade Educator

Problem 15

What is meant by a weighted average?

Amy Jiang

Numerade Educator

Problem 16

Explain how natural abundance percentages are related to average atomic masses.

Amy Jiang

Numerade Educator

Problem 17

Explain the inherent redundancy in the nuclide symbol $_{Z}^{A} X .$

Amy Jiang

Numerade Educator

Problem 18

How are the mass number and atomic number of a nuclide related to the number of neutrons and protons in each of its nuclei?

Amy Jiang

Numerade Educator

Problem 19

How many protons, neutrons, and electrons are there in the following atoms? (a) $^{14} \mathrm{C} ;$ (b) $^{59} \mathrm{Fe} ;$ (c) $^{90} \mathrm{Sr} ;$ (d) $^{210} \mathrm{Pb}$

Amy Jiang

Numerade Educator

Problem 20

How many protons, neutrons, and electrons are there in the following atoms? (a) $^{11} \mathrm{B} ;(\mathrm{b})^{19} \mathrm{F} ;(\mathrm{c})^{131} \mathrm{I}_{j}(\mathrm{d})^{222} \mathrm{Rn}$

Amy Jiang

Numerade Educator

Problem 21

If the mass number of an isotope is more than twice the atomic number, is the neutron-to-proton ratio less than, greater than, or equal to $1 ?$

Amy Jiang

Numerade Educator

Problem 22

In each of the following pairs of isotopes, which isotope has more protons and which has more neutrons? (a) $^{127}$ I or $^{131}$ I;
(b) $^{188} \operatorname{Re}$ or $^{188} \mathrm{W} ;(\mathrm{c})^{14} \mathrm{N}$ or $^{14} \mathrm{C}$

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 23

Fill in the missing information about atoms of the four nuclides in the following table.
$$\begin{array}{lllll}
\hline \text { Symbol } & ^{16} \mathrm{O} & ? & ? & ? \\
\hline \text { Number of Protons } & ? & 26 & ? & 79 \\
\hline \text { Number of Neutrons } & ? & 30 & ? & ? \\
\hline \text { Number of Electrons } & ? & ? & 50 & ? \\
\hline \text { Mass Number } & ? & ? & 118 & 197 \\
\hline
\end{array}$$

Amy Jiang

Numerade Educator

Problem 24

Fill in the missing information about atoms of the four nuclides in the following table.
$$\begin{array}{lcccc}
\hline \text { Symbol } & ^{27} \mathrm{Al} & ? & ? & ? \\
\hline \text { Number of Protons } & ? & 42 & ? & 92 \\
\hline \text { Number of Neutrons } & ? & 56 & ? & ? \\
\hline \text { Number of Electrons } & ? & ? & 60 & ? \\
\hline \text { Mass Number } & ? & ? & 143 & 238 \\
\hline
\end{array}$$

Amy Jiang

Numerade Educator

Problem 25

Boron, lithium, nitrogen, and neon each have two stable isotopes. In which of the following pairs of isotopes is the heavier isotope more abundant? (a) $^{\text {io }}$ B or $^{11}$ B (average atomic mass, $10.81 \mathrm{amu}$ ); (b) $^{6}$ Li or $^{7}$ Li (average atomic mass, $\left.6.941 \mathrm{amu}) ;(\mathrm{c})^{14} \mathrm{N} \text { or }^{15} \mathrm{N} \text { (average atomic mass, } 14.01 \mathrm{amu}\right)$
(d) $^{20}$ Ne or $^{22}$ Ne (average atomic mass, 20.18 amu)

Amy Jiang

Numerade Educator

Problem 26

The average atomic mass of copper is 63.546 amu. It is composed of copper- 63 and copper- 65 isotopes. The natural abundance of copper- $63(62.9296 \text { amu) is } 69.17 \% .$ What is the natural abundance of copper-65 $(64.9278$ amu)?

Amy Jiang

Numerade Educator

Problem 27

The 1997 mission to Mars included a small robot, the Sojourner, that analyzed the composition of Martian rocks. Magnesium oxide from a boulder dubbed "Barnacle Bill" was analyzed and found to have the following isotopic composition:
$$\begin{aligned}
&\\
&\begin{array}{cc}
\text { Mass (amu) } & \text { Natural Abundance (\%) } \\
\hline 39.9872 & 78.70 \\
\hline 40.9886 & 10.13 \\
\hline 41.9846 & 11.17 \\
\hline
\end{array}\\
&
\end{aligned}$$
If essentially all of the oxygen in the Martian $\mathrm{Mg} \mathrm{O}$ sample is oxygen-16 (which has an exact mass of 15.9948 amu), is the average atomic mass of magnesium on Mars the same as on Earth $(24.31 \mathrm{amu}) ?$

Ma Ednelyn Lim

Numerade Educator

Problem 28

Platinum has six isotopes: $^{190} \mathrm{Pt},^{192} \mathrm{Pt},^{194} \mathrm{Pt},^{195} \mathrm{Pt},^{196} \mathrm{Pt},$ and
$^{198} \mathrm{Pt}$
a. How many neutrons are there in each isotope?
b. The natural abundances of the six isotopes are $0.014 \%^{190} \mathrm{Pt}(189.96 \mathrm{amu}) ; 0.782 \%^{192} \mathrm{Pt}(191.96 \mathrm{amu})$
$32.967 \%^{194} \mathrm{Pt}(193.96 \mathrm{amu}) ; 33.832 \%^{195} \mathrm{Pt}(194.97 \mathrm{amu})$
$25.242 \%^{196} \mathrm{Pt}(195.97 \mathrm{amu}) ;$ and $7.163 \%^{198} \mathrm{Pt}$
$(197.97 \mathrm{amu}) .$ Calculate the average atomic mass of platinum and compare it with the value in the periodic table on the inside front cover.

Amy Jiang

Numerade Educator

Problem 29

Use the following table of abundances and masses of five naturally occurring titanium isotopes to calculate the mass of $^{48} \mathrm{Ti}$
$$\begin{array}{ccc}
\hline \text { Symbol } & \text { Mass (amu) } & \text { Natural Abundance (\%) } \\
\hline^{46} \mathrm{Ti} & 45.95263 & 8.25 \\
\hline^{47} \mathrm{Ti} & 46.9518 & 7.44 \\
\hline^{48} \mathrm{Ti} & ? & 73.72 \\
\hline^{49} \mathrm{Ti} & 48.94787 & 5.41 \\
\hline^{50} \mathrm{Ti} & 49.9448 & 5.18 \\
\hline \text { Average } & 47.87 & \\
\hline
\end{array}$$

Amy Jiang

Numerade Educator

Problem 30

Use the following table of abundances and masses of the three naturally occurring argon isotopes to calculate the mass of $^{40} \mathrm{Ar}$.
$$\begin{array}{ccc}
\hline \text { Symbol } & \text { Mass (amu) } & \text { Natural Abundance (\%) } \\
\hline^{36} \mathrm{Ar} & 35.96755 & 0.337 \\
\hline^{38} \mathrm{Ar} & 37.96272 & 0.063 \\
\hline^{40} \mathrm{Ar} & ? & 99.60 \\
\hline \text { Average } & 39.948 & \\
\hline
\end{array}$$

Amy Jiang

Numerade Educator

Problem 31

Mendeleev ordered the elements in his version of the periodic table according to their atomic masses instead of their atomic numbers. Why?

Amy Jiang

Numerade Educator

Problem 32

Why did Mendeleev not include the noble gases in his version of the periodic table?

Amy Jiang

Numerade Educator

Problem 33

Mendeleev arranged the elements on the left side of his periodic table according to the formulas of the binary compounds they form with oxygen, and he used those formulas as column labels. For example, group 1 of the modern periodic table was labeled " $\mathrm{R}_{2} \mathrm{O}^{\prime \prime}$ in Mendeleev's table, where "R" represented one of the elements in the group. What labels did Mendeleev use for groups $2,3,$ and 4 of the modern periodic table?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 34

Mendeleev arranged the elements on the right side of his periodic table according to the formulas of the binary compounds they form with hydrogen, and he used those formulas as column labels. Which groups of the modern periodic table were labeled "HR," "H $_{2} \mathrm{R}, "$ and " $\mathrm{H}_{3} \mathrm{R}^{n}$ in Mendeleev's table, where "R" represented one of the elements in the group?

Nicole Smina

Numerade Educator

Problem 35

Which element is most likely to form a cation with a $2+$ charge? (a) $\mathrm{S} ;$ (b) $\mathrm{P} ;$ (c) $\mathrm{Be} ;$ (d) $\mathrm{Al}$

Amy Jiang

Numerade Educator

Problem 36

Which element is most likely to form an anion with a $2-$ charge? (a) $\mathrm{S} ;$ (b) $\mathrm{P} ;$ (c) $\mathrm{Be} ;$ (d) $\mathrm{Al}$

Amy Jiang

Numerade Educator

Problem 37

Which ions have the same number of electrons as an atom of argon? (a) $\mathrm{S}^{2-} ;$ (b) $\mathrm{P}^{3-} ;$ (c) $\mathrm{Be}^{2+} ;$ (d) $\mathrm{Ca}^{2+}$

Amy Jiang

Numerade Educator

Problem 38

Which ions have the same number of electrons as an atom of krypton? (a) $\mathrm{Se}^{2-} ;$ (b) $\mathrm{As}^{3-} ;$ (c) $\mathrm{Ca}^{2+} ;$ (d) $\mathrm{K}^{+}$

Amy Jiang

Numerade Educator

Problem 39

Classify each of the following third-row elements as a metal, a metalloid, or a nonmetal: (a) $\mathrm{Mg} ;$ (b) $\mathrm{Al} ;$ (c) $\mathrm{Si}$
(d) $\mathrm{S} ;$ (e) $\mathrm{Ar}$

Amy Jiang

Numerade Educator

Problem 40

Classify each of the following fourth-row elements as a metal, a metalloid, or a nonmetal: (a) $\mathrm{Ti} ;$ (b) $\mathrm{Ni} ;$ (c) $\mathrm{As}$
(d) $\mathrm{Se} ;$ (e) $\mathrm{Kr}$

Amy Jiang

Numerade Educator

Problem 41

Classify each of the following fourth-row elements as an alkali metal, an alkaline earth metal, a transition metal, a halogen, or a noble gas: (a) $\mathrm{Br} ;$ (b) $\mathrm{Ca} ;$ (c) $\mathrm{K} ;$ (d) $\mathrm{Kr} ;$ (e) $\mathrm{V}$

Amy Jiang

Numerade Educator

Problem 42

Which element in the second row of the periodic table is
(a) a halogen; (b) an alkali metal; (c) an alkaline earth metal; (d) a noble gas?

Amy Jiang

Numerade Educator

Problem 43

Molecules of the explosive called TNT contain atoms of hydrogen and of the second-row elements in groups $14,15,$ and $16 .$ Which three elements are these?

Amy Jiang

Numerade Educator

Problem 44

Phosgene, a colorless, poisonous gas, was used as a chemical weapon during World War I. Despite its name, molecules of phosgene contain no atoms of phosphorus. Instead, they contain atoms of carbon, of the group 16 element in the second row of the periodic table, and of the group 17 element in the third row. What are the names and the atomic numbers of these last two elements?

Amy Jiang

Numerade Educator

Problem 45

The catalytic converters used to remove pollutants from automobile exhaust contain the compounds of several fairly expensive elements, including those described below. Which elements are they?
a. The group 10 transition metal in the fifth row of the periodic table.
b. The transition metal whose symbol is to the left of your answer to part (a).
c. The transition metal whose symbol is directly below your answer to part (a).

Amy Jiang

Numerade Educator

Problem 46

Compounds containing chlorine have long been used to disinfect the water in swimming pools, but in recent years a compound of a less corrosive halogen has become a popular alternative disinfectant. What is the name of this fourth-row element?

Amy Jiang

Numerade Educator

Problem 47

How does Dalton's atomic theory of matter explain the fact that when water is decomposed into hydrogen and oxygen gas, the volume of hydrogen is always twice that of oxygen?

Amy Jiang

Numerade Educator

Problem 48

In the internal combustion engines that power most automobiles, nitrogen and oxygen may combine to form NO. When NO in automobile exhaust is released into the atmosphere, it reacts with more oxygen, forming $\mathrm{NO}_{2},$ a key ingredient in smog. How do these reactions illustrate Dalton's law of multiple proportions?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 49

Describe the types of elements that combine to form molecular compounds and the types that combine to form ionic compounds.

Amy Jiang

Numerade Educator

Problem 50

How do the properties of ionic compounds differ from those of molecular compounds?

Amy Jiang

Numerade Educator

Problem 51

Cobalt forms two sulfides: $\operatorname{CoS}$ and $\mathrm{Co}_{2} \mathrm{S}_{3} .$ Predict the ratio of the two masses of sulfur that combine with a fixed mass of cobalt to form $\operatorname{CoS}$ and $\mathrm{Co}_{2} \mathrm{S}_{3}$

Amy Jiang

Numerade Educator

Problem 52

Lead forms two oxides: $\mathrm{PbO}$ and $\mathrm{Pb} \mathrm{O}_{2} .$ Predict the ratio of the two masses of oxygen that combine with a fixed mass of lead to form $\mathrm{PbO}$ and $\mathrm{PbO}_{2}$.

Amy Jiang

Numerade Educator

Problem 53

When $5.0 \mathrm{g}$ of sulfur is combined with $5.0 \mathrm{g}$ of oxygen, $10.0 \mathrm{g}$ of sulfur dioxide $\left(\mathrm{SO}_{2}\right)$ is formed. What mass of oxygen would be required to convert $5.0 \mathrm{g}$ of sulfur into sulfur trioxide $\left(\mathrm{SO}_{3}\right) ?$

Audrey Fleming

Numerade Educator

Problem 54

Nitrogen monoxide (NO) is $46.7 \%$ nitrogen by mass. Use the law of multiple proportions to calculate the mass percentage of nitrogen in nitrogen dioxide ( $\mathrm{NO}_{2}$ ).

Amy Jiang

Numerade Educator

Problem 55

Fill in the missing information in the following table of monatomic ions.$$\begin{array}{lcccc}
\hline \text { Symbol } & ^{35} \mathrm{Cl}^{-} & ? & ? & ? \\
\hline \text { Number of Protons } & ? & 11 & ? & 82 \\
\hline \text { Number of Neutrons } & ? & 12 & 46 & ? \\
\hline \text { Number of Electrons } & ? & 10 & 36 & 80 \\
\hline \text { Mass Number } & ? & ? & 81 & 210 \\
\hline
\end{array}$$

Amy Jiang

Numerade Educator

Problem 56

Fill in the missing information in the following table of monatomic ions.
$$\begin{array}{lcccc}
\hline \text { Symbol } & ^{137} \mathrm{Cs}^{+} & ? & ? & ? \\
\hline \text { Number of Protons } & ? & 30 & ? & 40 \\
\hline \text { Number of Neutrons } & ? & 34 & 16 & ? \\
\hline \text { Number of Electrons } & ? & 28 & 18 & 36 \\
\hline \text { Mass Number } & ? & ? & 32 & 90 \\
\hline
\end{array}$$

Amy Jiang

Numerade Educator

Problem 57

Which of these compounds consist of molecules, and which consist of ions? (a) $\mathrm{P}_{4} \mathrm{O}_{10} ;$ (b) $\mathrm{Sr} \mathrm{Cl}_{2} ;$ (c) $\mathrm{MgF}_{2} ;$ (d) $\mathrm{SO}_{3}$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 58

Which of these compounds consist of molecules, and which consist of ions? (a) $\mathrm{Mg}_{3} \mathrm{N}_{2} ;$ (b) $\mathrm{BaS} ;$ (c) $\mathrm{AgCl} ;$ (d) $\mathrm{NCl}_{3}$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 59

Would compounds formed from each pair of elements contain covalent bonds or ionic bonds? (a) cesium and fluorine; (b) nitrogen and chlorine; (c) carbon and oxygen;
(d) magnesium and oxygen

Amy Jiang

Numerade Educator

Problem 60

Would compounds formed from each pair of elements contain covalent bonds or ionic bonds? (a) silver and oxygen;
(b) sulfur and oxygen; (c) carbon and hydrogen; (d) barium and nitrogen

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 61

Give the total number of atoms in a formula unit of these compounds: (a) $\mathrm{LaF}_{3} ;$ (b) $\mathrm{In}_{2} \mathrm{S}_{3} ;$ (c) $\mathrm{Na}_{3} \mathrm{P} ;$ (d) $\mathrm{Ca}_{3} \mathrm{N}_{2}$

Amy Jiang

Numerade Educator

Problem 62

Give the total number of atoms in a formula unit of these compounds: (a) $\operatorname{In}_{2} \mathrm{O}_{3} ;$ (b) $\mathrm{CeS}_{2} ;$ (c) $\mathrm{TIF}_{3} ;$ (d) $\mathrm{CaO}$

Amy Jiang

Numerade Educator

Problem 63

Consider a mythical element $\mathrm{X}$, which forms only two oxoanions: $\mathrm{XO}_{2}^{2-}$ and $\mathrm{XO}_{3}^{2-} .$ Which of the two has a name that ends in -ite?

Amy Jiang

Numerade Educator

Problem 64

Concerning the oxoanions in Problem $2.63,$ would the name of either of them require a prefix such as bypo-or per-? Explain why or why not.

Amy Jiang

Numerade Educator

Problem 65

What is the role of Roman numerals in the names of the compounds formed by transition metals?

Amy Jiang

Numerade Educator

Problem 66

Why do the names of the ionic compounds formed by the alkali metals and by the alkaline earth metals not include Roman numerals?

Amy Jiang

Numerade Educator

Problem 67

What are the names of these compounds of nitrogen and oxygen? (a) $\mathrm{NO}_{3} ;$ (b) $\mathrm{N}_{2} \mathrm{O}_{5} ;$ (c) $\mathrm{N}_{2} \mathrm{O}_{4} ;$ (d) $\mathrm{NO}_{2}$

Amy Jiang

Numerade Educator

Problem 68

What are the names of these compounds of nitrogen and oxygen? (a) $\mathrm{N}_{2} \mathrm{O}_{3} ;$ (b) $\mathrm{NO} ;$ (c) $\mathrm{N}_{2} \mathrm{O} ;$ (d) $\mathrm{N}_{4} \mathrm{O}$

Amy Jiang

Numerade Educator

Problem 69

What are the formulas and names of the ionic compounds containing the following pairs of elements? (a) sodium and sulfur; (b) strontium and chlorine; (c) aluminum and oxygen; (d) lithium and hydrogen

Amy Jiang

Numerade Educator

Problem 70

What are the formulas and names of the ionic compounds containing the following pairs of elements? (a) potassium and bromine; (b) calcium and hydrogen; (c) lithium and nitrogen; (d) aluminum and chlorine

Amy Jiang

Numerade Educator

Problem 71

Milk of magnesia is a slurry of $\mathrm{Mg}(\mathrm{OH})_{2}$ in water. What is the chemical name of this compound?

Amy Jiang

Numerade Educator

Problem 72

Smelling salts are an antidote for fainting, made of $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3},$ which smells of ammonia. What is the chemical name of $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3} ?$

Amy Jiang

Numerade Educator

Problem 73

What are the names of these sodium compounds? (a) $\mathrm{Na}_{2} \mathrm{O}$
(b) $\mathrm{Na}_{2} \mathrm{S} ;$ (c) $\mathrm{Na}_{2} \mathrm{SO}_{4} ;$ (d) $\mathrm{NaNO}_{3} ;$ (e) $\mathrm{NaNO}_{2}$

Amy Jiang

Numerade Educator

Problem 74

What are the names of these potassium compounds?
(a) $\mathrm{K}_{3} \mathrm{PO}_{4} ;$ (b) $\mathrm{K}_{2} \mathrm{O} ;$ (c) $\mathrm{K}_{2} \mathrm{SO}_{3} ;$ (d) $\mathrm{KNO}_{3} ;$ (e) $\mathrm{KNO}_{2}$

Amy Jiang

Numerade Educator

Problem 75

What are the formulas of these compounds? (a) potassium sulfide; (b) potassium selenide; (c) rubidium sulfate;
(d) rubidium nitrite; (e) magnesium sulfate

Amy Jiang

Numerade Educator

Problem 76

What are the formulas of these compounds? (a) rubidium nitride; (b) potassium selenite; (c) rubidium sulfite;
(d) rubidium nitrate; (e) magnesium sulfite

Amy Jiang

Numerade Educator

Problem 77

What are the formulas of these compounds? (a) sodium hypobromite; (b) potassium sulfate; (c) lithium iodate;
(d) magnesium nitrite

Amy Jiang

Numerade Educator

Problem 78

What are the formulas of these compounds? (a) potassium tellurite; (b) sodium arsenate; (c) calcium selenite;
(d) potassium chlorate

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 79

Which compound is magnesium nitrite? (a) $\mathrm{Mg}_{3} \mathrm{N}$
(b) $\mathrm{Mg}\left(\mathrm{NO}_{2}\right)_{2} ;$ (c) $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2} ;$ (d) $\mathrm{Mg}(\mathrm{NO})_{2}$

Amy Jiang

Numerade Educator

Problem 80

Which compound is lithium phosphate? (a) $\mathrm{Li}_{3} \mathrm{P}$
(b) $\mathrm{Li}_{3} \mathrm{PO}_{3} ;(\mathrm{c}) \mathrm{Li}_{3} \mathrm{PO}_{4} ;(\mathrm{d}) \mathrm{Li}_{2}\left(\mathrm{PO}_{4}\right)_{3}$

Amy Jiang

Numerade Educator

Problem 81

Which of these chemical names is followed by a chemical formula that does not fit the name? (a) calcium oxide, $\mathrm{CaO}$
(b) lithium sulfate, $\operatorname{LiSO}_{4} ;$ (c) barium sulfide, BaS;
(d) potassium oxide, $\mathrm{K}_{2} \mathrm{O}$

Amy Jiang

Numerade Educator

Problem 82

Which of these chemical names is followed by a chemical formula that does not fit the name? (a) aluminum nitride, AlN; (b) aluminum sulfate, $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} ;$ (c) potassium chloride, $\mathrm{KCl}_{2} ;$ (d) cesium sulfate, $\mathrm{C} \mathrm{s}_{2} \mathrm{SO}_{4}$

Amy Jiang

Numerade Educator

Problem 83

The most abundant cations in blood plasma are $\mathrm{Na}^{+}, \mathrm{K}^{+}, \mathrm{Mg}^{2+},$ and $\mathrm{Ca}^{2+} .$ Two of the principal anions are $\mathrm{Cl}^{-}$ and $\mathrm{HPO}_{4}^{-} .$ Write the formulas of the eight ionic compounds these cations and anions form.

Amy Jiang

Numerade Educator

Problem 84

Evaporation of seawater gives a mixture of ionic compounds containing sodium combined with chloride, sulfate, carbonate, bicarbonate, bromide, fluoride, and tetrahydroborate, $\mathrm{B}(\mathrm{OH})_{4}^{-} .$ Write the chemical formulas of all these compounds.

Amy Jiang

Numerade Educator

Problem 85

What are the names of these compounds? (a) $\mathrm{Cr}_{2} \mathrm{Te}_{3}$
(b) $\mathrm{V}_{2}\left(\mathrm{SO}_{4}\right)_{3} ;$ (c) $\mathrm{Fe}_{2} \mathrm{CrO}_{4} ;$ (d) $\mathrm{MnO}$

Amy Jiang

Numerade Educator

Problem 86

What are the names of these compounds? (a) $\mathrm{FePO}_{4}$
(b) $\mathrm{CuSO}_{4} ;$ (c) $\mathrm{Ag}_{2} \mathrm{CO}_{3} ;$ (d) $\mathrm{Zn}\left(\mathrm{NO}_{2}\right)_{2}$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 87

What are the formulas for these transition metal compounds? (a) zinc dichromate; (b) iron(III) acetate;
(c) mercury(I) peroxide; (d) scandium thiocyanate

Amy Jiang

Numerade Educator

Problem 88

What are the formulas for these transition metal compounds? (a) mercury(II) hydroxide; (b) silver perchlorate; (c) manganese(IV) nitrate; (d) vanadium(IV) oxide

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 89

What are the formulas of the following copper minerals?
(a) cuprite, copper( $I$ ) oxide; (b) chalcocite, copper(I) sulfide; (c) covellite, copper(1I) sulfide

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 90

What are the names of the cobalt oxides with the following formulas? (a) $\mathrm{CoO} ;$ (b) $\mathrm{Co}_{2} \mathrm{O}_{3} ;$ (c) $\mathrm{CoO}_{2}$

Jorge Villanueva

Jorge Villanueva

Numerade Educator

Problem 91

What is the name of each of the following acids? (a) HF;
(b) $\mathrm{HBrO}_{3} ;$ (c) $\mathrm{HBr} ;$ (d) $\mathrm{HIO}_{4}$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 92

What are the formulas of the following acids? (a) selenous acid; (b) hydrocyanic acid; (c) phosphoric acid; (d) nitrous acid

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 93

What classes of organic compounds contain no heteroatoms?

Amy Jiang

Numerade Educator

Problem 94

What classes of organic compounds contain oxygen atoms?

Amy Jiang

Numerade Educator

Problem 95

What classes of organic compounds contain nitrogen atoms? Does any class of organic compounds contain both oxygen and nitrogen atoms?

Amy Jiang

Numerade Educator

Problem 96

Are organic compounds made of covalent or ionic bonds $=$ Do they exist as molecules or as ionic lattices?

Amy Jiang

Numerade Educator

Problem 97

To which class of organic compounds does each of the following compounds belong?
a. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}$ (octane-a
principal component of gasoline)
b. $\mathrm{HC} \equiv \mathrm{CH}$ (ethyne, also known as acetylene-used in welding torches)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 98

To which class of organic compounds does each of the following compounds belong?
a. $\mathrm{CH}_{3} \mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2} \mathrm{CH}_{3}$ (diethyl ether-once used
as anesthesia for surgery)
b. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}$ (butanol-a component of
brake fluids and perfumes)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 99

What is the functional group present in propyl acetate (the substance responsible for the smell of pears; Figure $\mathrm{P} 2.99) ?$
(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 100

What two functional groups are present in glycine (the simplest amino acid; Figure $\mathrm{P} 2.100$ )?
(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 101

Write brief (one-sentence) definitions of chemistry and cosmology, and then give as many examples as you can of how the two sciences are related.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 102

In the history of the universe, which of these particles formed first, and which formed last? (a) deuteron;
(b) neutron; (c) proton; (d) quark

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 103

Chemists do not include quarks in the category of subatomic particles. Why?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 104

Why did early nucleosynthesis last such a short time?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 105

In the current cosmological model, the volume of the universe is increasing with time. How might this expansion affect the density of the universe?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 106

Most of the ions in the solar wind emitted by the Sun are hydrogen ions. The ions of which element should be next most abundant?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 107

The molecular compounds $\mathrm{HClO}, \mathrm{HClO}_{2},$ and $\mathrm{HClO}_{4}$ are three of the four common oxoacids of chlorine. Give the formula and chemical name of the fourth oxoacid of chlorine.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 108

One reaction in the process of carbon fusion in massive stars involves the combination of two carbon- 12 nuclei to form the nucleus of a new element and an alpha particle. Write an equation that describes this process.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 109

A process called neon fusion takes place in massive stars. In one of the reactions in this process, an alpha particle combines with a neon- 21 nucleus to produce another element and a neutron. Write an equation that describes this process.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 110

In April 1897,J.J. Thomson presented the results of his experiment with cathode-ray tubes (Figure $\mathrm{P} 2.110$ ) in which he proposed that the rays were actually beams of negatively charged particles, which he called "corpuscles."
a. What is the name we use for these particles today?
b. Why did the beam deflect when passed between electrically charged plates, as shown in Figure P2.110?
c. If the polarity of the plates was switched, how would the position of the light spot on the phosphorescent screen change?
d. If the voltage on the plates was reduced by half, how would the position of the light spot change?(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 111

Suppose the electrically charged discs at the end of the cathode-ray tube were replaced with a radioactive source, as shown in Figure P2.111. Also suppose the radioactive material inside the source emits $\alpha$ and $\beta$ particles. The only way for either kind of particle to escape the source is through a narrow channel drilled through a block of lead.
a. How many light spots do you expect to see on the phosphorescent screen?
b. What are their positions relative to the electrical plates, and which particle produces which spot?(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 112

Suppose the radioactive material inside the source in the apparatus shown in Figure P2.111 emits protons and $\alpha$ particles, and suppose both kinds of particles have the same velocities.
A Mow many light spots do you expect to see on the phosphorescent screen?
b. What are their positions on the screen (above, at, or below the center)? Which particle produces which spot?
(FIGURE CAN'T COPY)

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 113

Cosmologists estimate that the matter in the early universe was $75 \%$ hydrogen- 1 and $25 \%$ helium- 4 by mass, when atoms first formed.
a. Assuming these proportions are correct, what was the ratio of hydrogen to helium atoms in the early universe?
b. The ratio of hydrogen to helium atoms in our solar system is slightly less than $10: 1 .$ Compare this value with the value you calculated in part (a).
c. Propose a hypothesis that accounts for the difference in composition between the solar system and the early universe.
d. Describe an experiment that would test your hypothesis.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 114

Potassium forms three compounds with oxygen: $\mathrm{K}_{2} \mathrm{O}$ (potassium oxide), $\mathrm{K}_{2} \mathrm{O}_{2}$ (potassium peroxide), and $\mathrm{KO}_{2}$ (potassium superoxide). Elemental potassium is rarely encountered; it reacts violently with water and is very corrosive to human tissue. Potassium superoxide is used in self-contained breathing apparatuses as a source of oxygen for use in mines, submarines, and spacecraft. Potassium peroxide binds carbon dioxide and is used to scrub (remove) toxic $\mathrm{CO}_{2}$ from the air in submarines. Predict the ratio of the masses of oxygen that combine with a fixed mass of potassium in $\mathrm{K}_{2} \mathrm{O}, \mathrm{K}_{2} \mathrm{O}_{2},$ and $\mathrm{KO}_{2}$

Kim Trang Nguyen

Kim Trang Nguyen

Numerade Educator

Problem 115

Historians and archaeologists often apply the term "Bronze Age" to the period in Mediterranean and Middle Eastern history when bronze was the preferred material for making weapons, tools, and other metal objects. Ancient bronze was an alloy prepared by blending molten copper $(88 \% \text { by mass })$ and tin $(12 \% \text { by mass }) .$ What is the ratio of copper to tin atoms in a piece of bronze with this composition?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 116

In his version of the periodic table, Mendeleev arranged elements according to the formulas of the compounds they formed with hydrogen and oxygen. The elements in one of his eight groups formed compounds with the generic formulas $\mathrm{MH}_{3}$ and $\mathrm{M}_{2} \mathrm{O}_{5},$ where $\mathrm{M}$ was the symbol of an element in the group. Which Roman numeral did Mendeleev assign to this group?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 117

In the Mendeleev table in Figure $2.11,$ there are no symbols for elements with predicted atomic masses of 44
$68,$ and 72
a. Which elements are these?
b. Mendeleev anticipated the later discovery of these three elements and gave them the tentative names
ekaaluminum, ekaboron, and ekasilicon, reflecting the probability that their properties would resemble those of aluminum, boron, and silicon, respectively. What are the modern names of ekaaluminum, ekaboron, and ekasilicon?
c. When were these elements finally discovered? To answer this question you may wish to consult a reference such as webelements.com.
(FIGURE CAN'T COPY)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 118

In chemical nomenclature, the prefix thio- is used to indicate that a sulfur atom has replaced an oxygen atom in the structure of a molecule or a polyatomic ion.
a. With this rule in mind, write the formula for the thiosulfate ion.
b. What is the formula of sodium thiosulfate?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 119

There are two stable isotopes of gallium. Their masses are 68.92558 and 70.9247050 amu. If the average atomic mass of gallium is 69.7231 amu, what is the natural abundance of the lighter isotope?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 120

There are two stable isotopes of bromine. Their masses are 78.9183 and 80.9163 amu. If the average atomic mass of bromine is 79.9091 amu, what is the natural abundance of the heavier isotope?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 121

Using the information in the previous question:
a. Predict the possible masses of individual molecules of $\mathrm{Br}_{2}$
b. Calculate the natural abundance of molecules with each of the masses predicted in part (a) in a sample of Br $_{2}$.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 122

There are three stable isotopes of magnesium. Their masses are $23.9850,24.9858,$ and 25.9826 amu. If the average atomic mass of magnesium is 24.3050 amu and the natural abundance of the lightest isotope is $78.99 \%,$ what are the natural abundances of the other two isotopes?

Ronald Prasad

Numerade Educator

Problem 123

Write the names and formulas of the following compounds from this list of elements: Li, Fe, Al, O, C, and N.
a. A molecular substance $A B_{2},$ where $A$ is a group 14 element and $\mathrm{B}$ is a group 16 element
b. An ionic compound $\mathrm{C}_{3} \mathrm{D}$, where $\mathrm{C}$ is a group 1 element and $D$ is a group 15 element

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 124

Write the chemical symbol of each of the following species:
(a) a cation with a mass number of $24,$ an atomic number of
12, and a charge of $2+;$ (b) a member of group 15 that has a charge of $3+, 48$ electrons, and 70 neutrons; (c) a noble gas atom with 48 neutrons.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 125

Predict some physical and chemical properties of radium (Ra). Predict the melting points of $\mathrm{RaCl}_{2}$ and $\mathrm{RaO}$. (Hint:
research the melting points of the other alkaline earth element chlorides and oxides.)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 126

From their positions in the periodic table, predict which of the following elements would be good electrical conductors: $\mathrm{Ti}, \mathrm{Ne}, \mathrm{N}, \mathrm{Ag}, \mathrm{Tb}, \mathrm{Br},$ and $\mathrm{Mo}$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 127

Argon has a larger average atomic mass than potassium, yet it is placed before potassium in the modern periodic table. Explain.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 128

It takes nearly twice the energy to remove an electron from a helium atom as it does to remove an electron from a hydrogen atom. Propose an explanation for this.

Catherine Lemar

Catherine Lemar

Numerade Educator