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Introduction to General, Organic and Biochemistry

Frederick A. Bettelheim, William H. Brown, Mary K. Campbell

Chapter 3

Chemical Bonds - all with Video Answers

Educators


Chapter Questions

03:13

Problem 1

Show how the following chemical changes obey the octet rule:
(a) A magnesium atom forms a magnesium ion, $\mathrm{Mg}^{2+}$
(b) A sulfur atom forms a sulfide ion, $\mathrm{S}^{2-}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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Problem 2

Judging from their relative positions in the Periodic Table, which element in each pair has the larger electronegativity?
(a) Lithium or potassium
(b) Nitrogen or phosphorus
(c) Carbon or silicon

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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03:40

Problem 3

Write the formulas for the ionic compounds formed from the following ions:
(a) Potassium ion and chloride ion
(b) Calcium ion and fluoride ion
(c) Iron(III) ion and oxide ion

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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02:36

Problem 4

Name these binary ionic compounds:
(a) $\mathrm{MgO}$
(b) $\mathrm{BaI}_{2}$
(c) $\mathrm{KCl}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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02:56

Problem 5

Write the formulas for these binary ionic compounds:
(a) Magnesium chloride
(b) Aluminum oxide
(c) Lithium iodide

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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03:15

Problem 6

Give each binary compound a systematic name and a common name.
(a) $\mathrm{FeO}$
(b) $\mathrm{Fe}_{2} \mathrm{O}_{3}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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03:22

Problem 7

Name these ionic compounds, each of which contains a polyatomic ion:
(a) $\mathrm{K}_{2} \mathrm{HPO}_{4}$
(b) $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}$
(c) $\mathrm{FeCO}_{3}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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03:59

Problem 8

Classify each bond as nonpolar covalent, polar covalent, or ionic.
(a) $\mathrm{S}-\mathrm{H}$
(b) $\mathrm{P}-\mathrm{H}$
(c) $\mathrm{C}-\mathrm{F}$
(d) $\mathrm{C}-\mathrm{Cl}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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02:45

Problem 9

Using the symbols $\delta-$ and $\delta+,$ indicate the polarity in each polar covalent bond.
(a) $\mathrm{C}-\mathrm{N}$
(b) $\mathrm{N}-\mathrm{O}$
(c) $\mathrm{C}-\mathrm{Cl}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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07:07

Problem 10

Draw a Lewis structure for each molecule. Each has only one possible order of attachment of its atoms, which is left for you to determine.
(a) Ethane, $\mathrm{C}_{2} \mathrm{H}_{6}$
(b) Chloromethane, $\mathrm{CH}_{3} \mathrm{Cl}$
(c) Hydrogen cyanide, HCN

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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03:47

Problem 11

Draw a Lewis structure of a covalent compound in which carbon has:
(a) Four single bonds
(b) Two single bonds and one double bond
(c) Two double bonds
(d) One single bond and one triple bond

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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05:22

Problem 12

Name these binary covalent compounds:
(a) $\mathrm{NO}_{2}$
(b) $\mathrm{PBr}_{3}$
(c) $\mathrm{SCl}_{2}$
(d) $\mathrm{BF}_{3}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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04:57

Problem 13

Draw the contributing structure indicated by the curved arrows. Be certain to show all valence electrons and all charges.

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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01:51

Problem 14

Which sets are valid pairs of contributing structures?

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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06:18

Problem 15

Predict all bond angles for these molecules:
(a) $\mathrm{CH}_{3} \mathrm{OH}$
(b) $\mathrm{CH}_{2} \mathrm{Cl}_{2}$
(c) $\mathrm{H}_{2} \mathrm{CO}_{3}$ (carbonic acid)

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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03:51

Problem 16

Which of these molecules are polar? Show the direction of the molecular dipole by using an arrow with a crossed tail.
(a) $\mathrm{H}_{2} \mathrm{S}$
(b) HCN
(c) $\mathrm{C}_{2} \mathrm{H}_{6}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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05:28

Problem 17

Answer true or false.
(a) The octet rule refers to the chemical bonding patterns of the first eight elements of the Periodic 'Table.
(b) The octet rule refers to the tendency of certain elements to react in such a way that they achieve an outer shell of eight valence electrons.
(c) In gaining electrons, an atom becomes a positively charged ion called a cation.
(d) When an atom forms an ion, only the number of valence electrons changes; the number of protons and neutrons in the nucleus does not change.
(e) In forming ions, Group 2 A elements typically lose two electrons to become cations with a charge of +2
(f) In forming an ion, a sodium atom $\left(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{1}\right)$ completes its valence shell by adding one electron to fill its 3 s shell $\left(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2}\right)$
(g) The elements of Group 6A typically react by accepting two electrons to become anions with a charge of -2
(h) With the exception of hydrogen, the octet rule applies to all elements in periods 1,2 and 3
(i) Atoms and the ions derived from them have very similar physical and chemical properties.

Rashmi Sinha
Rashmi Sinha
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03:35

Problem 18

How many electrons must each atom gain or lose to acquire an electron configuration identical to the noble gas nearest to it in atomic number?
(a) Li
(b) $\mathrm{Cl}$
(c) $\mathrm{P}$
(d) Al
(e) Sr
(f) $\mathrm{S}$
$(g) S i$
(h) $\mathrm{O}$

Ummatul Choudary
Ummatul Choudary
Numerade Educator
00:30

Problem 19

Show how each chemical change obeys the octet rule.
(a) Lithium forms Li $^{+}$
(b) Oxygen forms $\mathrm{O}^{2-}$

Lottie Adams
Lottie Adams
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00:36

Problem 20

Show how each chemical change obeys the octet rule.
(a) Hydrogen forms $\mathrm{H}^{-}$ (hydride ion)
(b) Aluminum forms $\mathrm{Al}^{3+}$

Lottie Adams
Lottie Adams
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03:51

Problem 21

Write the formula for the most stable ion formed by each element.
(a) $\mathrm{Mg}$
(b) $\mathbf{F}$
(c) $\mathrm{Al}$
(d) $\mathbf{S}$
(e) $\mathrm{K}$
(f) Br

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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02:06

Problem 22

Why is $\mathrm{Li}^{-}$ not a stable ion?

Hailey Tomashek
Hailey Tomashek
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02:31

Problem 23

Predict which ions are stable:
(a) $\mathrm{I}^{-}$
(b) $\mathrm{Se}^{2+}$
(c) $\mathrm{Na}^{+}$
(d) $\mathrm{S}^{2-}$
(e) $\mathrm{Li}^{2+}$
(f) $\mathrm{Ba}^{3+}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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01:13

Problem 24

Predict which ions are stable:
(a) $\mathrm{Br}^{2-}$
(b) $\mathrm{C}^{4-}$
(c) $\mathrm{Ca}^{+}$
(d) $A r^{+}$
(e) $\mathrm{Na}^{+}$
(f) $\mathrm{Cs}^{+}$

Lottie Adams
Lottie Adams
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01:17

Problem 25

Why are carbon and silicon reluctant to form ionic bonds?

Lottie Adams
Lottie Adams
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01:53

Problem 26

Table $3-2$ shows the following ions of copper: $\mathrm{Cu}^{+}$ and $\mathrm{Cu}^{2+}$. Do these violate the octet rule? Explain.

Anupa Sharad Medhekar
Anupa Sharad Medhekar
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03:19

Problem 27

Answer true or false.
(a) For Group $1 \mathrm{A}$ and Group $2 \mathrm{A}$ elements, the name of the ion each forms is simply the name of the element followed by the word ion; for example, $\mathrm{Mg}^{2+}$ is named magnesium ion.
(b) $\mathrm{H}^{+}$ is named hydronium ion, and $\mathrm{H}^{-}$ is named hydride ion.
(c) The nucleus of $\mathrm{H}^{+}$ consists of one proton and one neutron.
(d) Many transition and inner transition elements form more than one positively charged ion.
(e) In naming metal cations with two different charges, the suffix -ous refers to the ion with a charge of +1 and $-$ic refers to the ion with a charge of +2
(f) $\mathrm{Fe}^{3+}$ may be named either iron(III) ion or ferric ion.
(g) The anion derived from a bromine atom is named bromine ion.
(h) The anion derived from an oxygen atom is named oxide ion.
(i) $\mathrm{HCO}_{3}^{-}$ is named hydrogen carbonate ion.
(j) The prefix $b i-$ in the name "bicarbonate" ion indicates that this ion has a charge of -2
(k) The hydrogen phosphate ion has a charge of +1 and the dihydrogen phosphate ion has a charge of +2
(l) The phosphate ion is $\mathrm{PO}_{3}^{4-}$
$(\mathrm{m})$ The nitrite ion is $\mathrm{NO}_{2}^{-},$ and the nitrate ion is $\mathrm{NO}_{3}^{-}$
(n) The carbonate ion is $\mathrm{CO}_{3}^{2-}$, and the hydrogen carbonate ion is $\mathrm{HCO}_{3}^{-}$

Crystal Wang
Crystal Wang
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02:58

Problem 28

Name each polyatomic ion.
(a) $\mathrm{HCO}_{3}^{-}$
(b) $\mathrm{NO}_{2}$
(c) $\mathrm{SO}_{4}^{2-}$
(d) $\mathrm{HSO}_{4}^{-}$
(e) $\mathrm{H}_{2} \mathrm{PO}_{4}^{-}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
07:16

Problem 29

Answer true or false.
(a) According to the Lewis model of bonding, atoms bond together in such a way that each atom participating in the bond acquires an outer-shell electron configuration matching that of the noble gas nearest to it in atomic number.
(b) Atoms that lose electrons to achieve a filled valence shell become cations and form ionic
bonds with anions.
(c) Atoms that gain electrons to achieve filled valence shells become anions and form ionic
bonds with cations.
(d) Atoms that share electrons to achieve filled valence shells form covalent bonds.
(e) Ionic bonds tend to form between elements on the left side of the Periodic Table, and covalent bonds tend to form between elements on the right side of the Periodic Table.
(f) Ionic bonds tend to form between a metal and a
nonmetal.
(g) When two nonmetals combine, the bond between them is usually covalent.
(h) Electronegativity is a measure of an atom's attraction for the electrons it shares in a chemical bond with another atom.
(i) Electronegativity generally increases with atomic number.
(j) Electronegativity generally increases with atomic weight.
(k) Electronegativity is a periodic property.
(1) Fluorine, in the upper-right corner of the Periodic Table, is the most electronegative element; hydrogen, in the upper-left corner, is the least electronegative element.
(m)Electronegativity depends on both the nuclear charge and the distance of the valence electrons from the nucleus.
(n) Electronegativity generally increases from left to right across a period of the Periodic 'Table.
(o) Electronegativity generally increases from top to bottom in a column of the Periodic Table.

Ummatul Choudary
Ummatul Choudary
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00:26

Problem 30

Why does electronegativity generally increase going up a column (group) of the Periodic Table?

Lottie Adams
Lottie Adams
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00:42

Problem 31

Why does electronegativity generally increase going from left to right across a row of the Periodic Table?

Lottie Adams
Lottie Adams
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01:02

Problem 32

Judging from their relative positions in the Periodic Table, which element in each pair has the larger electronegativity?
(a) $\mathrm{F}$ or $\mathrm{Cl}$
(b) $\mathrm{O}$ or $\mathrm{S}$
(c) $\mathrm{C}$ or $\mathrm{N}$
(d) $C$ or $F$

Lottie Adams
Lottie Adams
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01:42

Problem 33

Toward which atom are the bonding electrons shifted in a covalent bond between each of the following pairs:
(a) $\mathrm{H}$ and $\mathrm{Cl}$
(b) $\mathrm{N}$ and $\mathrm{O}$
(c) $\mathrm{C}$ and $\mathrm{O}$
(d) $\mathrm{Cl}$ and $\mathrm{Br}$
(e) $C$ and $s$
(f) $P$ and $S$
(g) $\mathrm{H}$ and $\mathrm{O}$

Lottie Adams
Lottie Adams
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00:49

Problem 34

Which of these bonds is the most polar? The least polar?
(a) $\mathrm{C}-\mathrm{N}$
(b) $\mathrm{C}-\mathrm{C}$
(c) $\mathrm{C}-\mathrm{O}$

Lottie Adams
Lottie Adams
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00:55

Problem 35

Classify each bond as nonpolar covalent, polar covalent, or ionic.
(a) $\mathrm{C}-\mathrm{Cl}$
(b) $\mathrm{C}-\mathrm{Li}$
(c) $\mathrm{C}-\mathrm{N}$

Lottie Adams
Lottie Adams
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03:31

Problem 36

Classify each bond as nonpolar covalent, polar covalent, or ionic.
(a) $C-B r$
(b) $\mathrm{S}-\mathrm{Cl}$
(c) $\mathrm{C}-\mathrm{P}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
00:53

Problem 37

Answer true or false.
(a) An ionic bond is formed by the combination of positive and negative ions.
(b) An ionic bond between two atoms forms by the transfer of one or more valence electrons from the atom of higher electronegativity to the atom of lower electronegativity.
(c) As a rough guideline, we say that an ionic bond will form if the difference in electronegativity between two atoms is approximately 1.9 or greater.
(d) In forming $\mathrm{NaCl}$ from sodium and chlorine atoms, one electron is transferred from the valence shell of sodium to the valence shell of chlorine.
(e) The formula of sodium sulfide is $\mathrm{Na}_{2} \mathrm{S}$
(f) The formula of calcium hydroxide is CaOH.
(g) The formula of aluminum sulfide is AlS.
(h) The formula of iron(III) oxide is $\mathrm{Fe}_{3} \mathrm{O}_{2}$
(i) Barium ion is $\mathrm{Ba}^{2+}$, and oxide ion is $\mathrm{O}^{2-}$; therefore, the formula of barium oxide is $\mathrm{Ba}_{2} \mathrm{O}_{2}$

Lottie Adams
Lottie Adams
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03:09

Problem 38

Complete the chart by writing formulas for the compounds formed:
$$\begin{array}{|l|l|l|l|l|l|l|l|}
\hline & \mathrm{Br}^{-} & \mathrm{MnO}_{4}^{-} & \mathrm{O}^{2-} & \mathrm{NO}_{3}^{-} & \mathrm{SO}_{4}^{2-} & \mathrm{PO}_{4}^{3-} & \mathrm{OH}^{-} \\
\hline \mathrm{Li}^{*} & & & & & & & \\
\hline \mathrm{Ca}^{2+} & & & & & & & \\
\hline \mathrm{Co}^{3+} & & & & & & & \\
\hline \mathrm{K}^{*} & & & & & & & \\
\hline \mathrm{Cu}^{2+} & & & & & & & \\
\hline
\end{array}$$

Crystal Wang
Crystal Wang
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00:57

Problem 39

Write a formula for the ionic compound formed from each pair of elements.
(a) Sodium and bromine
(b) Sodium and oxygen
(c) Aluminum and chlorine
(d) Barium and chlorine
(e) Magnesium and oxygen

Lottie Adams
Lottie Adams
Numerade Educator
01:21

Problem 40

Although not a transition metal, lead can form $\mathrm{Pb}^{2+}$ and $\mathrm{Pb}^{4+}$ ions. Write the formula for the compound formed between each of these lead ions and the following anions:
(a) Chloride ion
(b) Hydroxide ion
(c) Oxide ion

Lottie Adams
Lottie Adams
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00:36

Problem 41

Describe the structure of sodium chloride in the solid state.

Lottie Adams
Lottie Adams
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01:01

Problem 42

What is the charge on each ion in these compounds?
(a) CaS
(b) $\mathrm{MgF}_{2}$
(c) $\mathrm{Cs}_{2} \mathrm{O}$
(d) $\mathrm{ScCl}_{3}$
(e) $\mathrm{Al}_{2} \mathrm{S}_{3}$

Lottie Adams
Lottie Adams
Numerade Educator
00:55

Problem 43

Write the formula for the compound formed from the following pairs of ions:
(a) Iron(III) ion and hydroxide ion
(b) Barium ion and chloride ion
(c) Calcium ion and phosphate ion
(d) Sodium ion and permanganate ion

Lottie Adams
Lottie Adams
Numerade Educator
00:38

Problem 44

Write the formula for the ionic compound formed from the following pairs of ions:
(a) Iron(II) ion and chloride ion
(b) Calcium ion and hydroxide ion
(c) Ammonium ion and phosphate ion
(d) Tin(II) ion and fluoride ion

Shazia Naz
Shazia Naz
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01:20

Problem 45

Which formulas are not correct? For each that is not correct, write the correct formula.
(a) Ammonium phosphate; $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{PO}_{4}$
(b) Barium carbonate; $\mathrm{Ba}_{2} \mathrm{CO}_{3}$
(c) Aluminum sulfide; $\mathrm{Al}_{2} \mathrm{S}_{3}$
(d) Magnesium sulfide; MgS

Lottie Adams
Lottie Adams
Numerade Educator
02:43

Problem 46

Which formulas are not correct? For each that is not correct, write the correct formula.
(a) Calcium oxide; $\mathrm{CaO}_{2}$
(b) Lithium oxide; $\mathrm{LiO}$
(c) Sodium hydrogen phosphate; $\mathrm{NaHPO}_{4}$
(d) Ammonium nitrate; $\mathrm{NH}_{4} \mathrm{NO}_{3}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
01:11

Problem 47

Answer true or false.
(a) The name of a binary ionic compound consists of the name of the positive ion followed by the name of the negative ion.
(b) In naming binary ionic compounds, it is necessary to state the number of each ion present in the compound.
(c) The formula of aluminum oxide is $\mathrm{Al}_{2} \mathrm{O}_{3}$
(d) Both copper(II) oxide and cupric oxide are acceptable names for CuO.
(e) The systematic name for $\mathrm{Fe}_{2} \mathrm{O}_{3}$ is iron(II) oxide.
(f) The systematic name for $\mathrm{FeCO}_{3}$ is iron carbonate.
(g) The systematic name for $\mathrm{NaH}_{2} \mathrm{PO}_{4}$ is sodium dihydrogen phosphate.
(h) The systematic name for $\mathrm{K}_{2} \mathrm{HPO}_{4}$ is dipotassium hydrogen phosphate.
(i) The systematic name for $\mathrm{Na}_{2} \mathrm{O}$ is sodium oxide.
(j) The systematic name for $\mathrm{PCl}_{3}$ is potassium chloride.
(k) The formula of ammonium carbonate is $\mathrm{NH}_{4} \mathrm{CO}_{3}$

Lottie Adams
Lottie Adams
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00:32

Problem 48

Potassium chloride and potassium bicarbonate are used as potassium dietary supplements. Write the formula of each compound.

Lottie Adams
Lottie Adams
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00:26

Problem 49

Potassium nitrite has been used as a vasodilator and as an antidote for cyanide poisoning. Write the formula of this compound.

Lottie Adams
Lottie Adams
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01:04

Problem 50

Name the polyatomic ion(s) in each compound.
(a) $\mathrm{Na}_{2} \mathrm{SO}_{3}$
(b) $\mathrm{KNO}_{3}$
(c) $\mathrm{Cs}_{2} \mathrm{CO}_{3}$
$(d) \mathrm{NH}_{4} \mathrm{OH}$
(e) $\mathrm{K}_{2} \mathrm{HPO}_{4}$
$(f) \mathrm{Ca}\left(\mathrm{ClO}_{4}\right)_{2}$

Lottie Adams
Lottie Adams
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06:18

Problem 51

Write the formulas for the ions present in each compound.
(a) NaBr
(b) $\mathrm{FeSO}_{3}$
(c) $\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{2}$
(d) $\mathrm{KH}_{2} \mathrm{PO}_{4}$
$(\mathrm{e}) \mathrm{NaHCO}_{3}$
$(f) B a\left(N O_{3}\right)_{2}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
04:22

Problem 52

Name these ionic compounds:
(a) $\mathrm{NaF}$
(b) $\mathrm{MgS}$
(c) $\mathrm{Al}_{2} \mathrm{O}_{3}$
(d) $\mathrm{BaCl}_{2}$
(e) $\mathrm{Ca}\left(\mathrm{HSO}_{3}\right)_{2}$
(f) KI
$(g) \operatorname{Sr}_{3}\left(P O_{4}\right)_{2}$
(h) $\mathrm{Fe}(\mathrm{OH})_{2}$
(i) $\mathrm{NaH}_{2} \mathrm{PO}_{4}$
(j) $\mathrm{Pb}\left(\mathrm{CH}_{3} \mathrm{COO}\right)_{2}$
(k) $\mathrm{BaH}_{2}$
(1) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{HPO}_{4}$

Ummatul Choudary
Ummatul Choudary
Numerade Educator
00:52

Problem 53

Write formulas for the following ionic compounds:
(a) Potassium bromide
(b) Calcium oxide
(c) Mercury(II) oxide
(d) Copper(II) phosphate
(e) Lithium sulfate
(f) Iron(III) sulfide

Lottie Adams
Lottie Adams
Numerade Educator
00:38

Problem 54

Write formulas for the following ionic compounds:
(a) Ammonium hydrogen sulfite
(b) Magnesium acetate
(c) Strontium dihydrogen phosphate
(d) Silver carbonate
(e) Strontium chloride
(f) Barium permanganate
(g) Aluminum perchlorate

Lottie Adams
Lottie Adams
Numerade Educator
06:28

Problem 55

Answer true or false.
(a) A covalent bond is formed between two atoms whose difference in electronegativity is less than 1.9
(b) If the difference in electronegativity between two atoms is zero (they have identical electronegativities $),$ then the two atoms will not form a covalent bond.
(c) A covalent bond formed by sharing two electrons is called a double bond.
(d) In the hydrogen molecule $\left(\mathrm{H}_{2}\right),$ the shared pair of electrons completes the valence shell of each hydrogen.
(e) In the molecule $\mathrm{CH}_{4}$, each hydrogen has an electron configuration like that of helium and carbon has an electron configuration like that of neon.
(f) In a polar covalent bond, the more electronegative atom has a partial negative charge $(\delta-)$ and the less electronegative atom has a partial positive charge $(\delta+)$
(g) These bonds are arranged in order of increasing polarity $\mathrm{C}-\mathrm{H}<\mathrm{N}-\mathrm{H}<\mathrm{O}-\mathrm{H}$
(h) These bonds are arranged in order of increasing polarity $\mathrm{H}-\mathrm{F}<\mathrm{H}-\mathrm{Cl}<\mathrm{H}-\mathrm{Br}$
(i) A polar bond has a dipole with the negative end located at the more electronegative atom.
(j) In a single bond, two atoms share one pair of electrons; in a double bond, they share two pairs of electrons; and in a triple bond, they share three pairs of electrons.
(k) The Lewis structure for ethane, $C_{2} H_{6},$ must show eight valence electrons.
(1) The Lewis structure for formaldehyde, $\mathrm{CH}_{2} \mathrm{O}$ must show 12 valence electrons.
(m) The Lewis structure for the ammonium ion, $\mathrm{NH}_{4}^{+},$ must show nine valence electrons.
(n) Atoms of third-period elements can hold more than eight electrons in their valence shells.

Crystal Wang
Crystal Wang
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01:10

Problem 56

How many covalent bonds are normally formed by each element?
(a) $\mathrm{N}$
(b) $\mathrm{F}$
(c) $\mathrm{C}$
(d) Br
(e) $\mathrm{O}$

Lottie Adams
Lottie Adams
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00:31

Problem 57

What is:
(a) A single bond?
(b) A double bond?
(c) A triple bond?

Lottie Adams
Lottie Adams
Numerade Educator
03:08

Problem 58

In Section $2-3 \mathrm{B}$, we saw that there are seven diatomic elements.
(a) Draw Lewis structures for each of these diatomic elements.
(b) Which diatomic elements are gases at room temperature? Which are liquids? Which are solids?

Crystal Wang
Crystal Wang
Numerade Educator
04:29

Problem 59

Draw a Lewis structure for each covalent compound.
(a) $\mathrm{CH}_{4}$
(b) $\mathrm{C}_{2} \mathrm{H}_{2}$
(c) $\mathrm{C}_{2} \mathrm{H}_{4}$
(d) $\mathrm{BF}_{3}$
(e) $\mathrm{CH}_{2} \mathrm{O}$
(f) $\mathrm{C}_{2} \mathrm{Cl}_{6}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
00:50

Problem 60

What is the difference between a molecular formula, a structural formula, and a Lewis structure?

Lottie Adams
Lottie Adams
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05:51

Problem 61

State the total number of valence electrons in each molecule.
(a) $\mathrm{NH}_{3}$
(b) $\mathrm{C}_{3} \mathrm{H}_{6}$
(c) $\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}$
(d) $\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}$
(e) $\mathrm{CCl}_{4}$
(f) $\mathrm{HNO}_{2}$
$(g) C C l_{2} F_{2}$
(h) $\mathrm{O}_{2}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
01:12

Problem 62

Draw a Lewis structure for each of the following molecules and ions. In each case, the atoms can be connected in only one way.
(a) $\mathrm{Br}_{2}$
(b) $\mathrm{H}_{2} \mathrm{S}$
(c) $\mathrm{N}_{2} \mathrm{H}_{4}$
(d) $\mathrm{N}_{2} \mathrm{H}_{2}$
(e) $\mathrm{CN}^{-}$
(f) $\mathrm{NH}_{4}^{+}$
$(g) N_{2}$
(h) $\mathrm{O}_{2}$

Lottie Adams
Lottie Adams
Numerade Educator
01:00

Problem 63

What is the difference between (a) a bromine atom,
(b) a bromine molecule, and (c) a bromide ion? Draw the Lewis structure for each.

Lottie Adams
Lottie Adams
Numerade Educator
01:35

Problem 64

Acetylene $\left(\mathrm{C}_{2} \mathrm{H}_{2}\right),$ hydrogen cyanide $(\mathrm{HCN}),$ and nitrogen $\left(\mathrm{N}_{2}\right)$ each contain a triple bond. Draw a Lewis structure for each molecule. Which of these are polar molecules, and which are nonpolar molecules?

Lottie Adams
Lottie Adams
Numerade Educator
00:44

Problem 65

Why can't hydrogen have more than two electrons in its valence shell?

Lottie Adams
Lottie Adams
Numerade Educator
01:04

Problem 66

Why can't second-row elements have more than eight electrons in their valence shells? That is, why does the octet rule work for second-row elements?

Lottie Adams
Lottie Adams
Numerade Educator
01:14

Problem 67

Why does nitrogen have three bonds and one unshared pair of electrons in covalent compounds?

Lottie Adams
Lottie Adams
Numerade Educator
01:20

Problem 68

Draw a Lewis structure of a covalent compound in which nitrogen has:
(a) Three single bonds and one unshared pair of electrons
(b) One single bond, one double bond, and one unshared pair of electrons
(c) One triple bond and one unshared pair of electrons

Lottie Adams
Lottie Adams
Numerade Educator
00:57

Problem 69

Why does oxygen have two bonds and two unshared pairs of electrons in covalent compounds?

Lottie Adams
Lottie Adams
Numerade Educator
01:19

Problem 70

Draw a Lewis structure of a covalent compound in which oxygen has:
(a) Two single bonds and two unshared pairs of electrons
(b) One double bond and two unshared pairs of electrons

Lottie Adams
Lottie Adams
Numerade Educator
01:03

Problem 71

The ion $\mathrm{O}^{6+}$ has a complete outer shell. Why is this ion not stable?

Lottie Adams
Lottie Adams
Numerade Educator
01:54

Problem 72

Draw a Lewis structure for a molecule in which a carbon atom is bonded by a double bond to (a) another carbon atom, (b) an oxygen atom, and (c) a nitrogen atom.

Lottie Adams
Lottie Adams
Numerade Educator
09:43

Problem 73

Which of the following molecules have an atom that does not obey the octet rule (not all of these are stable molecules)?
(a) $\mathrm{BF}_{3}$
(b) $\mathrm{CF}_{2}$
(c) $\mathrm{BeF}_{2}$
(d) $\mathrm{C}_{2} \mathrm{H}_{4}$
(e) $\mathrm{CH}_{3}$
(f) $\mathrm{N}_{2}$
$(g) N O$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
03:17

Problem 74

Answer true or false.
(a) A binary covalent compound contains two kinds of atoms.
(b) The two types of atoms in a binary covalent compound are named in this order: first the more electronegative element and then the less electronegative element.
(c) The name for $\mathrm{SF}_{2}$ is sulfur difluoride.
(d) The name for $\mathrm{CO}_{2}$, is carbon dioxide.
(e) The name for $C O$ is carbon oxide.
(f) The name for HBr is hydrogen bromide.
(g) The name for $\mathrm{CCl}_{4}$ is carbon tetrachloride.

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
01:04

Problem 75

Name these binary covalent compounds.
(a) $\mathrm{SO}_{2}$
(b) $\mathrm{SO}_{3}$
(c) $\mathrm{PCl}_{3}$
(d) $\mathrm{CS}_{2}$

Lottie Adams
Lottie Adams
Numerade Educator
01:19

Problem 76

Write two acceptable contributing structures for the bicarbonate ion, $\mathrm{HCO}_{3}^{-}$ and show by the use of curved arrows how the first contributing structure is converted to the second.

Lottie Adams
Lottie Adams
Numerade Educator
02:11

Problem 77

Ozone, $\mathrm{O}_{3}$, is an unstable blue gas with a characteristic pungent odor. In an ozone molecule, the connectivity of the atoms is $\mathrm{O}-\mathrm{O}-\mathrm{O}$ and both $\mathrm{O}-\mathrm{O}$ bonds are equivalent.
(a) How many valence electrons must be present in an acceptable Lewis structure for an ozone molecule?
(b) Write two equivalent resonance contributing structures for ozone. Be certain to show any positive or negative charges that may be present in your contributing structures. By equivalent contributing structures, we mean that each has the same pattern of bonding.
(c) Show by the use of curved arrows how the first of your contributing structures may be converted to the second.
(d) Based on your contributing structures, predict the $\mathrm{O}-\mathrm{O}-\mathrm{O}$ bond angle in ozone.
(e) Explain why the following is not an acceptable contributing structure for an ozone molecule:
$$\ddot{\mathrm{O}}-\ddot{\mathrm{O}}-\ddot{\mathrm{O}}$$

Lottie Adams
Lottie Adams
Numerade Educator
02:36

Problem 78

Nitrous oxide, $\mathrm{N}_{2} \mathrm{O}$, laughing gas, is a colorless, nontoxic, tasteless, and odorless gas. It is used as an inhalation anesthetic in dental and other surgeries. Because nitrous oxide is soluble in vegetable oils (fats), it is used commercially as a propellant in whipped toppings.
(a) How many valence electrons are present in a molecule of $\mathrm{N}_{2} \mathrm{O} ?$
(b) Write two equivalent contributing structures for this molecule. The connectivity in nitrous oxide is $\mathrm{N}-\mathrm{N}-\mathrm{O}$
(c) Explain why the following is not an acceptable contributing structure:
$$: \mathrm{N}-\mathrm{N}-\ddot{\mathrm{O}}$$

Lottie Adams
Lottie Adams
Numerade Educator
01:21

Problem 79

Answer true or false.
(a) The letters VSEPR stand for valence-shell electron-pair repulsion.
(b) In predicting bond angles about a central atom in a covalent molecule, the VSEPR model considers only shared electron pairs (electron pairs involved in forming covalent bonds)
(c) The VSEPR model treats the two electron pairs of a double bond as one region of electron density and the three electron pairs of a triple bond as one region of electron density.
(d) In carbon dioxide, $\mathrm{O}=\mathrm{C}=\mathrm{O},$ carbon is surrounded by four pairs of electrons and the
VSEPR model predicts $109.5^{\circ}$ for the $\mathrm{O}-\mathrm{C}-\mathrm{O}$ bond angle.
(e) For a central atom surrounded by three regions of electron density, the VSEPR model predicts bond angles of $120^{\circ}$
(f) The geometry about a carbon atom surrounded by three regions of electron density is described as trigonal planar.
(g) For a central atom surrounded by four regions of electron density, the VSEPR model predicts bond angles of $360^{\circ} / 4=90^{\circ}$
(h) For the ammonia molecule, $\mathrm{NH}_{3}$, the VSEPR model predicts H - N-H bond angles of $109.5^{\circ}$
(i) For the ammonium ion, $\mathrm{NH}_{4}^{+},$ the VSEPR model predicts $\mathrm{H}-\mathrm{N}-\mathrm{H}$ bond angles of $109.5^{\circ}$
(j) The VSEPR model applies equally well to covalent compounds of carbon, nitrogen, and oxygen.
(k) In water, $\mathrm{H}-\mathrm{O}-\mathrm{H}$, the oxygen atom forms covalent bonds to two other atoms, and therefore, the VSEPR model predicts an H-O-H bond angle of $180^{\circ}$
(l) If you fail to consider unshared pairs of valence electrons when you use the VSEPR model, you will arrive at an incorrect prediction.
(m) Given the assumptions of the VSEPR model, the only bond angles it predicts for compounds of carbon, nitrogen, and oxygen are $109.5^{\circ}, 120^{\circ}$ and $180^{\circ}$

Lottie Adams
Lottie Adams
Numerade Educator
01:57

Problem 80

State the shape of a molecule whose central atom is surrounded by:
(a) Two regions of electron density
(b) Three regions of electron density
(c) Four regions of electron density

Lottie Adams
Lottie Adams
Numerade Educator
01:32

Problem 81

Hydrogen and oxygen combine in different ratios to form $\mathrm{H}_{2} \mathrm{O}$ (water) and $\mathrm{H}_{2} \mathrm{O}_{2}$ (hydrogen peroxide).
(a) How many valence electrons are found in $\mathrm{H}_{2} \mathrm{O} ?$ $\operatorname{In} \mathrm{H}_{2} \mathrm{O}_{2} ?$
(b) Draw Lewis structures for each molecule in part
(a). Be certain to show all valence electrons.
(c) Using the VSEPR model, predict the bond angles about the oxygen atom in water and about each oxygen atom in hydrogen peroxide.

Lottie Adams
Lottie Adams
Numerade Educator
02:44

Problem 82

Hydrogen and nitrogen combine in different ratios to form three compounds: $\mathrm{NH}_{3}\left(\text { ammonia) }, \mathrm{N}_{2} \mathrm{H}_{4}\right.$ (hydrazine), and $\mathrm{N}_{2} \mathrm{H}_{2}$ (diimide).
(a) How many valence electrons must the Lewis structure of each molecule show?
(b) Draw a Lewis structure for each molecule.
(c) Predict the bond angles about the nitrogen atom(s) in each molecule.

Lottie Adams
Lottie Adams
Numerade Educator
05:31

Problem 83

Predict the shape of each molecule.
(a) $\mathrm{CH}_{4}$
(b) $\mathrm{PH}_{3}$
(c) $\mathrm{CHF}_{3}$
$(d) \operatorname{SO}_{2}$
$(\mathrm{e}) \mathrm{SO}_{3}$
(f) $\mathrm{CCl}_{2} \mathrm{F}_{2}$
$(g) N H_{3}$
(h) $\mathrm{PCl}_{3}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
01:46

Problem 84

Predict the shape of each ion.
(a) $\mathrm{NO}_{2}^{-}$
(b) $\mathrm{NH}_{4}^{+}$
(c) $\mathrm{CO}_{3}^{2-}$

Lottie Adams
Lottie Adams
Numerade Educator
01:26

Problem 85

Answer true or false.
(a) To predict whether a covalent molecule is polar or nonpolar, you must know both the polarity of each bond and the geometry (shape) of the molecule.
(b) A molecule may have two or more polar bonds and still be nonpolar.
(c) All molecules with polar bonds are polar.
(d) If water were a linear molecule with an $\mathrm{H}-\mathrm{O}-\mathrm{H}$ bond angle of $180^{\circ},$ water would be a nonpolar molecule.
(e) $\mathrm{H}_{2} \mathrm{O}$ and $\mathrm{NH}_{3}$ are polar molecules, but $\mathrm{CH}_{4}$ is nonpolar.
(f) In methanol, $\mathrm{CH}_{3} \mathrm{OH}$, the $\mathrm{O}-\mathrm{H}$ bond is more polar than the $\mathrm{C}-\mathrm{O}$ bond.
(g) Dichloromethane, $\mathrm{CH}_{2} \mathrm{Cl}_{2}$, is polar, but tetrachloromethane, $\mathrm{CCl}_{4},$ is nonpolar.
(h) Ethanol, $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$, the alcohol of alcoholic beverages, has polar bonds, has a net dipole, and is a polar molecule.

Lottie Adams
Lottie Adams
Numerade Educator
01:38

Problem 86

Both $\mathrm{CO}_{2}$ and $\mathrm{SO}_{2}$ have polar bonds. Account for the fact that $\mathrm{CO}_{2}$ is nonpolar and $\mathrm{SO}_{2}$ is polar.

Lottie Adams
Lottie Adams
Numerade Educator
03:24

Problem 87

Consider the molecule boron trifluoride, $\mathrm{BF}_{3}$
(a) Write a Lewis structure for $\mathrm{BF}_{3}$
(b) Predict the $F-B-F$ bond angles using the VSEPR model.
(c) Does $\mathrm{BF}_{3}$ have polar bonds? Is it a polar molecule?

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
00:29

Problem 88

Is it possible for a molecule to have polar bonds and yet have no dipole? Explain.

Lottie Adams
Lottie Adams
Numerade Educator
00:54

Problem 89

Is it possible for a molecule to have no polar bonds and yet have a dipole? Explain.

Lottie Adams
Lottie Adams
Numerade Educator
03:27

Problem 90

In each case, tell whether the bond is ionic, polar covalent, or nonpolar covalent.
(a) $\mathrm{Br}_{2}$
(b) BrCl
(c) $\mathrm{HCl}$
(d) $\operatorname{Sr} \mathrm{F}_{2}$
(e) $\operatorname{SiH}_{4}$
(f) $\mathrm{CO}$
$(g) N_{2}$
(h) $\mathrm{CsCl}$

Crystal Wang
Crystal Wang
Numerade Educator
01:44

Problem 91

Account for the fact that chloromethane, $\mathrm{CH}_{3} \mathrm{Cl}$ which has only one polar $\mathrm{C}-\mathrm{Cl}$ bond, is a polar molecule, but carbon tetrachloride, $\mathrm{CCl}_{4},$ which has four polar $\mathrm{C}-\mathrm{Cl}$ bonds, is a nonpolar molecule.

Lottie Adams
Lottie Adams
Numerade Educator
00:44

Problem 92

(Chemical Connections 3 A) What are the three main inorganic components of one dry mixture currently used to create synthetic bone?

Lottie Adams
Lottie Adams
Numerade Educator
00:31

Problem 93

(Chemical Connections $3 \mathrm{B}$ ) Why is sodium iodide often present in the table salt we buy at the grocery store?

Lottie Adams
Lottie Adams
Numerade Educator
00:37

Problem 94

(Chemical Connections $3 \mathrm{B}$ ) What is a medical use of barium sulfate?

Lottie Adams
Lottie Adams
Numerade Educator
00:31

Problem 95

(Chemical Connections $3 \mathrm{B}$ ) What is a medical use of potassium permanganate?

Lottie Adams
Lottie Adams
Numerade Educator
00:39

Problem 96

(Chemical Connections 3 A) What is the most prevalent metal ion in bone and tooth enamel?

Lottie Adams
Lottie Adams
Numerade Educator
00:38

Problem 97

(Chemical Connections $3 \mathrm{C}$ ) In what way does the gas nitric oxide, NO, contribute to the acidity of acid rain?

Lottie Adams
Lottie Adams
Numerade Educator
00:42

Problem 98

Explain why argon does not form either (a) ionic bonds or (b) covalent bonds.

Lottie Adams
Lottie Adams
Numerade Educator
01:12

Problem 99

Knowing what you do about covalent bonding in compounds of carbon, nitrogen, and oxygen and given the fact that silicon is just below carbon in the Periodic Table, phosphorus is just below nitrogen, and sulfur is just below oxygen, predict the molecular formula for the compound formed by
(a) silicon and chlorine,
(b) phosphorus and hydrogen, and
(c) sulfur and hydrogen.

Lottie Adams
Lottie Adams
Numerade Educator
01:14

Problem 100

Use the valence-shell electron-pair repulsion model to predict the shape of a molecule in which a central atom is surrounded by five regions of electron density-as, for example, in phosphorus pentafluoride, $\mathrm{PF}_{5}$. (Hint: Use molecular models or if you do not have a set handy, use marshmallows or gumdrops and toothpicks.)

Lottie Adams
Lottie Adams
Numerade Educator
04:21

Problem 101

Use the valence-shell electron-pair repulsion model to predict the shape of a molecule in which a central atom is surrounded by six regions of electron density, as, for example, in sulfur hexa-fluoride, $\mathrm{SF}_{6}$

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
00:42

Problem 102

Chlorine dioxide, $\mathrm{ClO}_{2}$, is a yellow to reddish yellow gas at room temperature. This strong oxidizing agent is used for bleaching cellulose, paper pulp, and textiles and for water purification. It was the gas used to kill anthrax spores in the anthraxcontaminated Hart Senate Office Building.
(a) How many valence electrons are present in $\mathrm{ClO}_{2}$ ?
(b) Draw a Lewis structure for this molecule. (Hint:
The order of attachment of atoms in this molecule is $\mathrm{O}-\mathrm{Cl}-\mathrm{O}$. Chlorine is a third-period element, and its valence shell may contain more than eight electrons.)

Lottie Adams
Lottie Adams
Numerade Educator
00:35

Problem 103

Using the information in Figure $2-16$, estimate the $\mathrm{H}-\mathrm{O}$ and $\mathrm{H}-\mathrm{S}$ distances (the atom-atom distances $)$ in $\mathrm{H}_{2} \mathrm{O}$ and $\mathrm{H}_{2} \mathrm{S}$, respectively.

Lottie Adams
Lottie Adams
Numerade Educator
01:53

Problem 104

Arrange the single covalent bonds within each set in order of increasing polarity.
(a) $\mathrm{C}-\mathrm{H}, \mathrm{O}-\mathrm{H}, \mathrm{N}-\mathrm{H}$
(b) $\mathrm{C}-\mathrm{H}, \mathrm{C}-\mathrm{Cl}, \mathrm{C}-\mathrm{I}$
(c) $\mathrm{C}-\mathrm{C}, \mathrm{C}-\mathrm{O}, \mathrm{C}-\mathrm{N}$

Lottie Adams
Lottie Adams
Numerade Educator
01:20

Problem 105

Consider the structure of Vitamin E shown below, which is found most abundantly in wheat germ oil, sunflower, and safflower oils:
(a) Identify the various types of geometries present in each central atom using VSEPR theory.
(b) Determine the various relative bond angles associated with each central atom using VSEPR theory.
(c) Which is the most polar bond in Vitamin E?
(d) Would you predict Vitamin E to be polar or nonpolar?

Lottie Adams
Lottie Adams
Numerade Educator
01:24

Problem 106

Consider the structure of Penicillin G shown below, an antibiotic used to treat bacterial infections caused by gram-positive organisms, derived from Penicillium fungi:
(a) Identify the various types of geometries present in each central atom using VSEPR theory.
(b) Determine the various relative bond angles associated with each central atom using VSEPR theory.
(c) Which is the most polar bond in Penicillin G?
(d) Would you predict Penicillin G to be polar or nonpolar?

Lottie Adams
Lottie Adams
Numerade Educator
01:07

Problem 107

Ephedrine, a molecule at one time found in the dietary supplement ephedra, has been linked to adverse health reactions, such as heart attacks, strokes, and heart palpitations. The use of ephedra in dietary supplements is now banned by the FDA.
(a) Which is the most polar bond in ephedra?
(b) Would you predict ephedra to be polar or nonpolar?

Lottie Adams
Lottie Adams
Numerade Educator
00:57

Problem 108

Allene, $\mathrm{C}_{3} \mathrm{H}_{4},$ has the structural formula $\mathrm{CH}_{2}=\mathrm{C}=\mathrm{CH}_{2}$
(a) Describe the shape of this molecule.
(b) Is allene polar or nonpolar?

Lottie Adams
Lottie Adams
Numerade Educator
04:21

Problem 109

Until several years ago, the two chlorofluorocarbons (CFCs) most widely used as heat transfer media in refrigeration systems were Freon-11 (trichlorofluoromethane, $\mathrm{CCl}_{3} \mathrm{F}$ ) and Freon-12 (dichlorodifluoromethane, $\mathrm{CCl}_{2} \mathrm{F}_{2}$ ). Draw a three-dimensional representation of each molecule and indicate the direction of its polarity.

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
00:28

Problem 110

Name and write the formula for the fluorinecontaining compound present in fluoridated toothpastes and dental gels.

Lottie Adams
Lottie Adams
Numerade Educator
00:23

Problem 111

If you read the labels of sun-blocking lotions, you will find that a common UV-blocking agent is a compound containing zinc. Name and write the formula of this zinc-containing compound.

Lottie Adams
Lottie Adams
Numerade Educator
00:25

Problem 112

On packaged table salt, it is common to see a label stating that the salt "supplies iodide, a necessary nutrient." Name and write the formula of the iodinecontaining nutrient compound found in iodized salt.

Lottie Adams
Lottie Adams
Numerade Educator
01:08

Problem 113

We are constantly warned about the dangers of "lead-based" paints. Name and write the formula for a lead-containing compound found in lead-based paints.

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
00:32

Problem 114

If you read the labels of several liquid and tablet antacid preparations, you will find that in many of them, the active ingredients are compounds containing hydroxide ions. Name and write formulas for these hydroxide ion-containing compounds.

Lottie Adams
Lottie Adams
Numerade Educator
00:36

Problem 115

Iron forms $\mathrm{Fe}^{2+}$ and $\mathrm{Fe}^{3+}$ ions. Which ion is found
in over-the-counter preparations intended to treat "iron-poor blood"?

Lottie Adams
Lottie Adams
Numerade Educator
01:12

Problem 116

Read the labels of several multivitamin/multimineral formulations. Among their components, you will find a number of so-called trace minerals-minerals required in the diet of a healthy adult in amounts less than $100 \mathrm{mg}$ per day or present in the body in amounts less than $0.01 \%$ of total body weight. Following are 18 trace minerals. Name at least one form of each trace mineral present in multivitamin formulations.
(a) Phosphorus
(b) Magnesium
(c) Potassium
(d) Iron
(e) Calcium
(f) Zinc
$(g)$ Manganese
(h) Titanium
(i) Silicon
(j) Copper
(k) Boron
(l) Molybdenum
$(\mathrm{m}) \mathrm{Chromium}$
(n) Iodine
(o) Selenium
(p) Vanadium
(q) Nickel
(r) Tin

Lottie Adams
Lottie Adams
Numerade Educator
00:59

Problem 117

Write formulas for these compounds.
(a) Calcium sulfite, which is used in preserving cider and other fruit juices
(b) Calcium hydrogen sulfite, which is used in dilute aqueous solutions for washing casks in brewing to prevent souring and cloudiness of beer and to prevent secondary fermentation
(c) Calcium hydroxide, which is used in mortar, plaster, cement, and other building and paving materials
(d) Calcium hydrogen phosphate, which is used in animal feeds and as a mineral supplement in cereals and other foods

Lottie Adams
Lottie Adams
Numerade Educator
02:51

Problem 118

Many paint pigments contain transition metal compounds. Name the compounds in these pigments using a Roman numeral to show the charge on a transition metal ion.
(a) Yellow, CdS
(b) Green, $\mathrm{Cr}_{2} \mathrm{O}_{3}$
(c) White, $\mathrm{TiO}_{2}$
(d) Purple, $\mathrm{Mn}_{3}\left(\mathrm{PO}_{4}\right)_{2}$
(e) Blue, $\mathrm{Co}_{2} \mathrm{O}_{3}$
(f) Ochre, $\mathrm{Fe}_{2} \mathrm{O}_{3}$

Crystal Wang
Crystal Wang
Numerade Educator
01:44

Problem 119

Perchloroethylene, which is a liquid at room temperature, is one of the most widely used solvents for commercial dry cleaning. It is sold for this purpose under several trade names, including Perclene Does this molecule have polar bonds? Is it a polar molecule? Does it have a dipole?

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
04:11

Problem 120

Vinyl chloride is the starting material for the production of poly(vinyl chloride), abbreviated PVC. Its recycling code is "V". The major use of PVC is for tubing in residential and commercial construction (Section $12-7$ ).
(a) Complete the Lewis structure for vinyl chloride by showing all unshared pairs of electrons.
(b) Predict the $\mathrm{H}-\mathrm{C}-\mathrm{H}, \mathrm{H}-\mathrm{C}-\mathrm{C},$ and $\mathrm{Cl}-\mathrm{C}-\mathrm{H}$
bond angles in this molecule.
(c) Does vinyl chloride have polar bonds? Is it a polar molecule? Does it have a dipole?

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
05:49

Problem 121

Tetrafluoroethylene is the starting material for the production of poly(tetrafluoroethylene), PTFE, a polymer that is widely used for the preparation of nonstick coatings on kitchenware (Section $12-7$ ). The most widely known trade name for this product is Teflon".
(a) Complete the Lewis structure for tetrafluoroethylene by showing all unshared pairs of electrons.
(b) Predict the $\mathrm{F}-\mathrm{C}-\mathrm{F}$ and $\mathrm{F}-\mathrm{C}-\mathrm{C}$ bond angles in this molecule.
(c) Does tetrafluoroethylene have polar bonds? Is it a polar molecule? Does it have a dipole?

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator
01:04

Problem 122

Some of the following structural formulas are incorrect because they contain one or more atoms that do not have their normal number of covalent bonds. Which
structural formulas are incorrect, and which atom or atoms in each have the incorrect number of bonds?

Lottie Adams
Lottie Adams
Numerade Educator
00:51

Problem 123

Sodium borohydride, $\mathrm{NaBH}_{4}$, has found wide use as a reducing agent in organic chemistry. It is an ionic compound composed of one sodium ion, $\mathrm{Na}^{+}$, and one borohydride ion, $\mathrm{BH}_{4}^{-}$
(a) How many valence electrons are present in the borohydride ion?
(b) Draw a Lewis structure for the borohydride ion.
(c) Predict the $\mathrm{H}-\mathrm{B}-\mathrm{H}$ bond angles in the borohydride ion.

Lottie Adams
Lottie Adams
Numerade Educator
02:39

Problem 124

Given your answer to Problem $3-123$ and knowing that aluminum is immediately below boron in column $3 \mathrm{A}$ of the Periodic Table, propose a structure for lithium aluminum hydride, another widely used reducing agent in organic chemistry.

Crystal Wang
Crystal Wang
Numerade Educator
10:16

Problem 125

In Chapter $27,$ you will learn that adenosine $5^{\prime}$ triphosphate (ATP) serves as a common currency into which the energy gained from food is converted and stored for use during muscle contraction. Consider the structure of ATP ( $\mathbf{\boldsymbol { }}$ refer to the structure at bottom of page)
(a) Identify the various types of geometries present in each central atom using VSEPR theory.
(b) Determine the various relative bond angles associated with each central atom using VSEPR theory.
(c) What is the most polar bond in ATP?
(d) Would you predict ATP to be polar or nonpolar?

Natalie Johns
Natalie Johns
Numerade Educator
01:00

Problem 126

Androstenedione, a muscle-building dietary supplement that is allowed in baseball but is banned in professional football, college athletics, and the Olympic sports (see Chemical Connections $21 \mathrm{C}$ ), has the following formula:
(a) Identify the various types of geometries present in each central atom using VSEPR theory.
(b) Determine the various relative bond angles associated with each central atom using VSEPR theory.
(c) What is the most polar bond in androstenedione?
(d) Would you predict androstenedione to be polar or nonpolar?

Lottie Adams
Lottie Adams
Numerade Educator
01:32

Problem 127

Amoxicillin is an antibiotic used to treat bacterial infections caused by susceptible microorganisms. Consider the skeletal structure of amoxicillin ( $\mathbf{v}$ refer to the structure at bottom of page). where all the bonded atoms are shown but double bonds, triple bonds, and/or lone pairs are missing:
(a) Complete the structure of amoxicillin.
(b) Identify the various types of geometries present in each central atom using VSEPR theory.
(c) Determine the various relative bond angles associated with each central atom using VSEPR theory.
(d) What is the most polar bond in Amoxicillin?
(e) Would you predict amoxicillin to be polar or nonpolar?
(f) Is amoxicillin expected to possess resonance? Explain why or why not.

Lottie Adams
Lottie Adams
Numerade Educator
06:45

Problem 128

Cyclopropane, an anesthetic with extreme reactivity under normal conditions, consists of three carbon atoms linked to each other to form a ring with a for$\operatorname{mula} \mathrm{C}_{3} \mathrm{H}_{6}$
(a) Based on this description, draw a Lewis structure for this molecule.
(b) Identify the geometry present in each central carbon atom using VSEPR theory.
(c) What is the predicted bond angle associated with each central carbon atom using VSEPR theory?
(d) What do you predict is the actual observed C-C-C bond angle, given the shape and size of the ring?
(e) Explain why cyclopropane is considerably less stable than other three-carbon compounds that do not contain a ring.

Anupa Sharad Medhekar
Anupa Sharad Medhekar
Numerade Educator