Chemistry

Raymond Chang, Jason Overby

Chapter 22

Nonmetallic Elements and Their Compounds - all with Video Answers

Educators

Chapter Questions

Problem 1

Without referring to Figure $22.1,$ state whether each of the following elements are metals, metalloids, or nonmetals: (a) $\mathrm{Cs},(\mathrm{b}) \mathrm{Ge},(\mathrm{c}) \mathrm{I},$ (d) $\mathrm{Kr},$ (e) $\mathrm{W}$, (f) $\mathrm{Ga},(\mathrm{g}) \mathrm{Te},(\mathrm{h}) \mathrm{Bi}$

Kyle Gassaway

Kyle Gassaway

Numerade Educator

Problem 2

List two chemical and two physical properties that distinguish a metal from a nonmetal.

Arpit Gupta

Numerade Educator

Problem 3

Make a list of physical and chemical properties of chlorine $\left(\mathrm{Cl}_{2}\right)$ and magnesium. Comment on their differences with reference to the fact that one is a metal and the other is a nonmetal.

Arpit Gupta

Numerade Educator

Problem 4

Carbon is usually classified as a nonmetal. However, the graphite used in "lead" pencils conducts electricity. Look at a pencil and list two nonmetallic properties of graphite.

Kyle Gassaway

Numerade Educator

Problem 5

Explain why hydrogen has a unique position in the periodic table.

Arpit Gupta

Numerade Educator

Problem 6

Describe two laboratory and two industrial preparations for hydrogen.

Kyle Gassaway

Numerade Educator

Problem 7

Hydrogen exhibits three types of bonding in its compounds. Describe each type of bonding with an example.

Kyle Gassaway

Numerade Educator

Problem 8

What are interstitial hydrides?

Kyle Gassaway

Numerade Educator

Problem 9

Give the name of (a) an ionic hydride and (b) a covalent hydride. In each case describe the preparation and give the structure of the compound.

Arpit Gupta

Numerade Educator

Problem 10

Describe what is meant by the "hydrogen economy."

Kyle Gassaway

Numerade Educator

Problem 11

Elements number 17 and 20 form compounds with hydrogen. Write the formulas for these two compounds and compare their chemical behavior in water.

Kyle Gassaway

Numerade Educator

Problem 12

Give an example of hydrogen as (a) an oxidizing agent and (b) a reducing agent.

Arpit Gupta

Numerade Educator

Problem 13

Compare the physical and chemical properties of the hydrides of each of the following elements: $\mathrm{Na}$, $\mathrm{Ca}, \mathrm{C}, \mathrm{N}, \mathrm{O}, \mathrm{Cl}$.

Arpit Gupta

Numerade Educator

Problem 14

Suggest a physical method that would enable you to separate hydrogen gas from neon gas.

Arpit Gupta

Numerade Educator

Problem 15

Write a balanced equation to show the reaction between $\mathrm{CaH}_{2}$ and $\mathrm{H}_{2} \mathrm{O}$. How many grams of $\mathrm{CaH}_{2}$ are needed to produce $26.4 \mathrm{~L}$ of $\mathrm{H}_{2}$ gas at $20^{\circ} \mathrm{C}$ and $746 \mathrm{mmHg} ?$

Arpit Gupta

Numerade Educator

Problem 16

How many kilograms of water must be processed to obtain $2.0 \mathrm{~L}$ of $\mathrm{D}_{2}$ at $25^{\circ} \mathrm{C}$ and 0.90 atm pressure? Assume that deuterium abundance is 0.015 percent and that recovery is 80 percent.

Kyle Gassaway

Numerade Educator

Problem 17

Predict the outcome of the following reactions:
(a) $\mathrm{CuO}(s)+\mathrm{H}_{2}(g) \longrightarrow$
(b) $\mathrm{Na}_{2} \mathrm{O}(s)+\mathrm{H}_{2}(g) \longrightarrow$

Arpit Gupta

Numerade Educator

Problem 18

Starting with $\mathrm{H}_{2}$, describe how you would prepare
(a) $\mathrm{HCl}$,
(b) $\mathrm{NH}_{3},$
(c) LiOH.

Kyle Gassaway

Numerade Educator

Problem 19

Give an example of a carbide and a cyanide.

Kyle Gassaway

Numerade Educator

Problem 20

How are cyanide ions used in metallurgy?

Arpit Gupta

Numerade Educator

Problem 21

Briefly discuss the preparation and properties of carbon monoxide and carbon dioxide.

Kyle Gassaway

Numerade Educator

Problem 22

What is coal?

Anand Jangid

Numerade Educator

Problem 23

Explain what is meant by coal gasification.

Kyle Gassaway

Numerade Educator

Problem 24

Describe two chemical differences between CO and $\mathrm{CO}_{2}$.

Arpit Gupta

Numerade Educator

Problem 25

Describe the reaction between $\mathrm{CO}_{2}$ and $\mathrm{OH}^{-}$ in terms of a Lewis acid-base reaction such as that shown in Section 15.12 .

Nicole Krahulik

Nicole Krahulik

Numerade Educator

Problem 26

Draw a Lewis structure for the $\mathrm{C}_{2}^{2-}$ ion.

Kyle Gassaway

Numerade Educator

Problem 27

Balance the following equations:
(a) $\mathrm{Be}_{2} \mathrm{C}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow$
(b) $\mathrm{CaC}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow$

Arpit Gupta

Numerade Educator

Problem 28

Unlike $\mathrm{CaCO}_{3}, \mathrm{Na}_{2} \mathrm{CO}_{3}$ does not readily yield $\mathrm{CO}_{2}$ when heated. On the other hand, $\mathrm{NaHCO}_{3}$ undergoes thermal decomposition to produce $\mathrm{CO}_{2}$ and $\mathrm{Na}_{2} \mathrm{CO}_{3}$. (a) Write a balanced equation for the reaction. (b) How would you test for the $\mathrm{CO}_{2}$ evolved? [Hint: Treat the gas with limewater, an aqueous solution of $\left.\mathrm{Ca}(\mathrm{OH})_{2} .\right]$

Anand Jangid

Numerade Educator

Problem 29

Two solutions are labeled A and B. Solution A contains $\mathrm{Na}_{2} \mathrm{CO}_{3}$ and solution $\mathrm{B}$ contains $\mathrm{NaHCO}_{3}$. Describe how you would distinguish between the two solutions if you were provided with a $\mathrm{MgCl}_{2}$ solution. (Hint: You need to know the solubilities of $\mathrm{MgCO}_{3}$ and $\mathrm{MgHCO}_{3}$.)

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 30

Magnesium chloride is dissolved in a solution containing sodium bicarbonate. On heating, a white precipitate is formed. Explain what causes the precipitation.

Kyle Gassaway

Numerade Educator

Problem 31

A few drops of concentrated ammonia solution added to a calcium bicarbonate solution cause a white precipitate to form. Write a balanced equation for the reaction.

Kyle Gassaway

Numerade Educator

Problem 32

Sodium hydroxide is hygroscopic-that is, it absorbs moisture when exposed to the atmosphere. A student placed a pellet of $\mathrm{NaOH}$ on a watch glass. A few days later, she noticed that the pellet was covered with a white solid. What is the identity of this solid? (Hint: Air contains $\mathrm{CO}_{2}$.)

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 33

A piece of red-hot magnesium ribbon will continue to burn in an atmosphere of $\mathrm{CO}_{2}$ even though $\mathrm{CO}_{2}$ does not support combustion. Explain.

Arpit Gupta

Numerade Educator

Problem 34

Is carbon monoxide isoelectronic with nitrogen $\left(\mathrm{N}_{2}\right) ?$

Kyle Gassaway

Numerade Educator

Problem 35

Describe a laboratory and an industrial preparation of nitrogen gas.

Kyle Gassaway

Numerade Educator

Problem 36

What is meant by nitrogen fixation? Describe a process for fixation of nitrogen on an industrial scale.

Kyle Gassaway

Numerade Educator

Problem 37

Describe an industrial preparation of phosphorus.

Arpit Gupta

Numerade Educator

Problem 38

Why is the $\mathrm{P}_{4}$ molecule unstable?

Arpit Gupta

Numerade Educator

Problem 39

Nitrogen can be obtained by (a) passing ammonia over red-hot copper(II) oxide and (b) heating ammonium dichromate [one of the products is $\mathrm{Cr}(\mathrm{III})$ oxide $] .$ Write a balanced equation for each preparation.

Arpit Gupta

Numerade Educator

Problem 40

Write balanced equations for the preparation of sodium nitrite by heating (a) sodium nitrate, (b) sodium nitrate with carbon.

Kyle Gassaway

Numerade Educator

Problem 41

Sodium amide $\left(\mathrm{NaNH}_{2}\right)$ reacts with water to produce sodium hydroxide and ammonia. Describe this reaction as a Brønsted acid-base reaction.

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 42

Write a balanced equation for the formation of urea, $\left(\mathrm{NH}_{2}\right)_{2} \mathrm{CO},$ from carbon dioxide and ammonia. Should the reaction be run at high or low pressure to maximize the yield?

Arpit Gupta

Numerade Educator

Problem 43

Some farmers believe that lightning helps produce a better crop. What is the scientific basis for this belief?

Anand Jangid

Numerade Educator

Problem 44

At $620 \mathrm{~K}$ the vapor density of ammonium chloride relative to hydrogen $\left(\mathrm{H}_{2}\right)$ under the same conditions of temperature and pressure is $14.5,$ although, according to its formula mass, it should have a vapor density of $26.8 .$ How would you account for this discrepancy?

Arpit Gupta

Numerade Educator

Problem 45

Explain, giving one example in each case, why nitrous acid can act as both a reducing agent and an oxidizing agent.

Kyle Gassaway

Numerade Educator

Problem 46

Explain why nitric acid can be reduced but not oxidized.

Arpit Gupta

Numerade Educator

Problem 47

Write a balanced equation for each of the following processes: (a) On heating, ammonium nitrate produces nitrous oxide. (b) On heating, potassium nitrate produces potassium nitrite and oxygen gas. (c) On heating, lead nitrate produces lead(II) oxide, nitrogen dioxide $\left(\mathrm{NO}_{2}\right),$ and oxygen gas.

Kyle Gassaway

Numerade Educator

Problem 48

Explain why, under normal conditions, the reaction of zinc with nitric acid does not produce hydrogen.

Arpit Gupta

Numerade Educator

Problem 49

Potassium nitrite can be produced by heating a mixture of potassium nitrate and carbon. Write a balanced equation for this reaction. Calculate the theoretical yield of $\mathrm{KNO}_{2}$ produced by heating $57.0 \mathrm{~g}$ of $\mathrm{KNO}_{3}$ with an excess of carbon.

Kyle Gassaway

Numerade Educator

Problem 50

Predict the geometry of nitrous oxide, $\mathrm{N}_{2} \mathrm{O},$ by the VSEPR method and draw resonance structures for the molecule. (Hint: The atoms are arranged as NNO.)

Arpit Gupta

Numerade Educator

Problem 51

Consider the reaction
$$\mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{NO}(g)$$
Given that the $\Delta G^{\circ}$ for the reaction at $298 \mathrm{~K}$ is $173.4 \mathrm{~kJ} / \mathrm{mol},$ calculate (a) the standard free energy of formation of $\mathrm{NO},$ (b) $K_{P}$ for the reaction, $(\mathrm{c}) K_{\mathrm{c}}$ for the reaction.

Arpit Gupta

Numerade Educator

Problem 52

From the data in Appendix $2,$ calculate $\Delta H^{\circ}$ for the synthesis of NO (which is the first step in the manufacture of nitric acid) at $25^{\circ} \mathrm{C}$ :
$$4 \mathrm{NH}_{3}(g)+5 \mathrm{O}_{2}(g) \longrightarrow 4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(l)$$

Arpit Gupta

Numerade Educator

Problem 53

Explain why two $\mathrm{N}$ atoms can form a double bond or a triple bond, whereas two $\mathrm{P}$ atoms normally can form only a single bond.

Arpit Gupta

Numerade Educator

Problem 54

When $1.645 \mathrm{~g}$ of white phosphorus are dissolved in $75.5 \mathrm{~g}$ of $\mathrm{CS}_{2},$ the solution boils at $46.709^{\circ} \mathrm{C}$
whereas pure $\mathrm{CS}_{2}$ boils at $46.300^{\circ} \mathrm{C}$. The molal boiling-point elevation constant for $\mathrm{CS}_{2}$ is $2.34^{\circ} \mathrm{C} / \mathrm{m}$. Calculate the molar mass of white phosphorus and give the molecular formula.

Arpit Gupta

Numerade Educator

Problem 55

Starting with elemental phosphorus, $\mathrm{P}_{4}$, show how you would prepare phosphoric acid.

Arpit Gupta

Numerade Educator

Problem 56

Dinitrogen pentoxide is a product of the reaction between $\mathrm{P}_{4} \mathrm{O}_{10}$ and $\mathrm{HNO}_{3}$. Write a balanced equation for this reaction. Calculate the theoretical yield of $\mathrm{N}_{2} \mathrm{O}_{5}$ if $79.4 \mathrm{~g}$ of $\mathrm{P}_{4} \mathrm{O}_{10}$ are reacted with an excess of $\mathrm{HNO}_{3}$. (Hint: One of the products is $\mathrm{HPO}_{3}$.)

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 57

Explain why (a) $\mathrm{NH}_{3}$ is more basic than $\mathrm{PH}_{3}$ (b) $\mathrm{NH}_{3}$ has a higher boiling point than $\mathrm{PH}_{3}$, (c) $\mathrm{PCl}_{5}$ exists but $\mathrm{NCl}_{5}$ does not, $(\mathrm{d}) \mathrm{N}_{2}$ is more inert than $\mathrm{P}_{4}$.

Kyle Gassaway

Numerade Educator

Problem 58

What is the hybridization of phosphorus in the phosphonium ion, $\mathrm{PH}_{4}^{+} ?$.

Kyle Gassaway

Numerade Educator

Problem 59

Describe one industrial and one laboratory preparation of $\mathrm{O}_{2}$.

Arpit Gupta

Numerade Educator

Problem 60

Give an account of the various kinds of oxides that exist and illustrate each type by two examples.

Kyle Gassaway

Numerade Educator

Problem 61

Hydrogen peroxide can be prepared by treating barium peroxide with sulfuric acid. Write a balanced equation for this reaction.

Arpit Gupta

Numerade Educator

Problem 62

Describe the Frasch process for obtaining sulfur.

Arpit Gupta

Numerade Educator

Problem 63

Describe the contact process for the production of sulfuric acid.

Kyle Gassaway

Numerade Educator

Problem 64

How is hydrogen sulfide generated in the laboratory?

Kyle Gassaway

Numerade Educator

Problem 65

Draw molecular orbital energy level diagrams for $\mathrm{O}_{2}, \mathrm{O}_{2}^{-},$ and $\mathrm{O}_{2}^{2-}$.

Arpit Gupta

Numerade Educator

Problem 66

One of the steps involved in the depletion of ozone in the stratosphere by nitric oxide may be represented as
$$\mathrm{NO}(g)+\mathrm{O}_{3}(g) \longrightarrow \mathrm{NO}_{2}(g)+\mathrm{O}_{2}(g)$$
From the data in Appendix 2 calculate $\Delta G^{\circ}, K_{P}$, and $K_{\mathrm{c}}$ for the reaction at $25^{\circ} \mathrm{C}$

Arpit Gupta

Numerade Educator

Problem 67

Hydrogen peroxide is unstable and decomposes readily:
$$2 \mathrm{H}_{2} \mathrm{O}_{2}(a q) \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{O}_{2}(g)$$
This reaction is accelerated by light, heat, or a catalyst. (a) Explain why hydrogen peroxide sold in drugstores comes in dark bottles. (b) The concentrations of aqueous hydrogen peroxide solutions are normally expressed as percent by mass. In the decomposition of hydrogen peroxide, how many liters of oxygen gas can be produced at STP from $15.0 \mathrm{~g}$ of a 7.50 percent hydrogen peroxide solution?

Kyle Gassaway

Numerade Educator

Problem 68

What are the oxidation numbers of $\mathrm{O}$ and $\mathrm{F}$ in $\mathrm{HFO} ?$

Arpit Gupta

Numerade Educator

Problem 69

Oxygen forms double bonds in $\mathrm{O}_{2}$, but sulfur forms single bonds in $\mathrm{S}_{8}$. Explain.

Arpit Gupta

Numerade Educator

Problem 70

In 2008 , about 48 million tons of sulfuric acid were produced in the United States. Calculate the amount of sulfur (in grams and moles) used to produce that amount of sulfuric acid.

Nicole Krahulik

Nicole Krahulik

Numerade Educator

Problem 71

Sulfuric acid is a dehydrating agent. Write balanced equations for the reactions between sulfuric acid and the following substances:
(a) $\mathrm{HCOOH}$
(b) $\mathrm{H}_{3} \mathrm{PO}_{4}$
(c) $\mathrm{HNO}_{3}$, (d) $\mathrm{HClO}_{3}$. (Hint: Sulfuric acid is not decomposed by the dehydrating action.)

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 72

Calculate the amount of $\mathrm{CaCO}_{3}$ (in grams) that would be required to react with $50.6 \mathrm{~g}$ of $\mathrm{SO}_{2}$ emitted by a power plant.

Arpit Gupta

Numerade Educator

Problem 73

$\mathrm{SF}_{6}$ exists but $\mathrm{OF}_{6}$ does not. Explain.

Arpit Gupta

Numerade Educator

Problem 74

Explain why $\mathrm{SCl}_{6}, \mathrm{SBr}_{6},$ and $\mathrm{SI}_{6}$ cannot be prepared.

Arpit Gupta

Numerade Educator

Problem 75

Compare the physical and chemical properties of $\mathrm{H}_{2} \mathrm{O}$ and $\mathrm{H}_{2} \mathrm{~S}$.

Kyle Gassaway

Numerade Educator

Problem 76

The bad smell of water containing hydrogen sulfide can be removed by the action of chlorine. The reaction is
$$\mathrm{H}_{2} \mathrm{~S}(a q)+\mathrm{Cl}_{2}(a q) \longrightarrow 2 \mathrm{HCl}(a q)+\mathrm{S}(s)$$
If the hydrogen sulfide content of contaminated water is 22 ppm by mass, calculate the amount of $\mathrm{Cl}_{2}$ (in grams) required to remove all the $\mathrm{H}_{2} \mathrm{~S}$ from $2.0 \times 10^{2}$ gallons of water. ( 1 gallon $=3.785$ L.)

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 77

Describe two reactions in which sulfuric acid acts as an oxidizing agent.

Arpit Gupta

Numerade Educator

Problem 78

Concentrated sulfuric acid reacts with sodium iodide to produce molecular iodine, hydrogen sulfide, and sodium hydrogen sulfate. Write a balanced equation for the reaction.

Arpit Gupta

Numerade Educator

Problem 79

Describe an industrial method for preparing each of the halogens.

Arpit Gupta

Numerade Educator

Problem 80

Name the major uses of the halogens.

Arpit Gupta

Numerade Educator

Problem 81

Metal chlorides can be prepared in a number of ways: (a) direct combination of metal and molecular chlorine, (b) reaction between metal and hydrochloric acid, (c) acid-base neutralization, (d) metal carbonate treated with hydrochloric acid, (e) precipitation reaction. Give an example for each type of preparation.

Arpit Gupta

Numerade Educator

Problem 82

Sulfuric acid is a weaker acid than hydrochloric acid. Yet hydrogen chloride is evolved when concentrated sulfuric acid is added to sodium chloride. Explain.

Arpit Gupta

Numerade Educator

Problem 83

Show that chlorine, bromine, and iodine are very much alike by giving an account of their behavior (a) with hydrogen, (b) in producing silver salts, (c) as oxidizing agents, and (d) with sodium hydroxide. (e) In what respects is fluorine not a typical halogen element?

Arpit Gupta

Numerade Educator

Problem 84

A 375 -gallon tank is filled with water containing $167 \mathrm{~g}$ of bromine in the form of $\mathrm{Br}^{-}$ ions. How many liters of $\mathrm{Cl}_{2}$ gas at 1.00 atm and $20^{\circ} \mathrm{C}$ will be required to oxidize all the bromide to molecular bromine?

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 85

Draw structures for (a) (HF) $_{2}$, (b) $\mathrm{HF}_{2}^{-}$.

Kyle Gassaway

Numerade Educator

Problem 86

Hydrogen fluoride can be prepared by the action of sulfuric acid on sodium fluoride. Explain why hydrogen bromide cannot be prepared by the action of the same acid on sodium bromide.

Kyle Gassaway

Numerade Educator

Problem 87

Aqueous copper(II) sulfate solution is blue. When aqueous potassium fluoride is added to the $\mathrm{CuSO}_{4}$ solution, a green precipitate is formed. If aqueous potassium chloride is added instead, a bright-green solution is formed. Explain what happens in each case.

Adriano Chikande

Adriano Chikande

Numerade Educator

Problem 88

What volume of bromine $\left(\mathrm{Br}_{2}\right)$ vapor measured at $100^{\circ} \mathrm{C}$ and $700 \mathrm{mmHg}$ pressure would be obtained if $2.00 \mathrm{~L}$ of dry chlorine $\left(\mathrm{Cl}_{2}\right),$ measured at $15^{\circ} \mathrm{C}$ and $760 \mathrm{mmHg}$, were absorbed by a potassium bromide solution?

Arpit Gupta

Numerade Educator

Problem 89

Use the VSEPR method to predict the geometries of the following species: (a) $\mathrm{I}_{3}^{-},$ (b) $\mathrm{SiCl}_{4},$ (c) $\mathrm{PF}_{5}$, (d) $\mathrm{SF}_{4}$.

Kyle Gassaway

Numerade Educator

Problem 90

Iodine pentoxide, $\mathrm{I}_{2} \mathrm{O}_{5}$, is sometimes used to remove carbon monoxide from the air by forming carbon dioxide and iodine. Write a balanced equation for this reaction and identify species that are oxidized and reduced.

Arpit Gupta

Numerade Educator

Problem 91

Write a balanced equation for each of the following reactions: (a) Heating phosphorous acid yields phosphoric acid and phosphine $\left(\mathrm{PH}_{3}\right) .$ (b) Lithium carbide reacts with hydrochloric acid to give lithium chloride and methane. (c) Bubbling HI gas through an aqueous solution of $\mathrm{HNO}_{2}$ yields molecular iodine and nitric oxide. (d) Hydrogen sulfide is oxidized by chlorine to give $\mathrm{HCl}$ and $\mathrm{SCl}_{2}$.

Arpit Gupta

Numerade Educator

Problem 92

(a) Which of the following compounds has the greatest ionic character: $\mathrm{PCl}_{5}, \mathrm{SiCl}_{4}, \mathrm{CCl}_{4}, \mathrm{BCl}_{3} ?$
(b) Which of the following ions has the smallest ionic radius: $\mathrm{F}^{-}, \mathrm{C}^{4-}, \mathrm{N}^{3-}, \mathrm{O}^{2-} ?(\mathrm{c})$ Which of the
following atoms has the highest ionization energy: $\mathrm{F}, \mathrm{Cl}, \mathrm{Br}, \mathrm{I} ?(\mathrm{~d})$ Which of the following oxides is
most acidic: $\mathrm{H}_{2} \mathrm{O}, \mathrm{SiO}_{2}, \mathrm{CO}_{2} ?$

Jorge Villanueva

Jorge Villanueva

Numerade Educator

Problem 93

Both $\mathrm{N}_{2} \mathrm{O}$ and $\mathrm{O}_{2}$ support combustion. Suggest one physical and one chemical test to distinguish between the two gases.

Kyle Gassaway

Numerade Educator

Problem 94

What is the change in oxidation number for the following reaction?
$$3 \mathrm{O}_{2} \longrightarrow 2 \mathrm{O}_{3}$$

Kyle Gassaway

Numerade Educator

Problem 95

Describe the bonding in the $\mathrm{C}_{2}^{2-}$ ion in terms of the molecular orbital theory.

Kyle Gassaway

Numerade Educator

Problem 96

Starting with deuterium oxide $\left(\mathrm{D}_{2} \mathrm{O}\right),$ describe how you would prepare
(a) $\mathrm{NaOD}$
(b) DCl,
(c) $\mathrm{ND}_{3}$
(d) $\mathrm{C}_{2} \mathrm{D}_{2}$
(e) $\mathrm{CD}_{4}$,
(f) $\mathrm{D}_{2} \mathrm{SO}_{4}$.

Arpit Gupta

Numerade Educator

Problem 97

Solid $\mathrm{PCl}_{5}$ exists as $\left[\mathrm{PCl}_{4}^{+}\right]\left[\mathrm{PCl}_{6}^{-}\right] .$ Draw Lewis structures for these ions. Describe the hybridization state of the $\mathrm{P}$ atoms.

Arpit Gupta

Numerade Educator

Problem 98

Consider the Frasch process. (a) How is it possible to heat water well above $100^{\circ} \mathrm{C}$ without turning it into steam? (b) Why is water sent down the outermost pipe? (c) Why would excavating a mine and digging for sulfur be a dangerous procedure for obtaining the element?

Arpit Gupta

Numerade Educator

Problem 99

Predict the physical and chemical properties of astatine, a radioactive element and the last member of Group 7A.

Arpit Gupta

Numerade Educator

Problem 100

Lubricants used in watches usually consist of longchain hydrocarbons. Oxidation by air forms solid polymers that eventually destroy the effectiveness of the lubricants. It is believed that one of the initial steps in the oxidation is removal of a hydrogen atom (hydrogen abstraction). By replacing the hydrogen atoms at reactive sites with deuterium atoms, it is possible to substantially slow the overall oxidation rate. Why? (Hint: Consider the kinetic isotope effect.)

Anand Jangid

Numerade Educator

Problem 101

How are lightbulbs frosted? (Hint: Consider the action of hydrofluoric acid on glass, which is made of silicon dioxide.

Anand Jangid

Numerade Educator

Problem 102

Life evolves to adapt to its environment. In this respect, explain why life most frequently needs oxygen for survival, rather than the more abundant nitrogen.

Arpit Gupta

Numerade Educator

Problem 103

As mentioned in Chapter 3 , ammonium nitrate is the most important nitrogen-containing fertilizer in the world. Given only air and water as starting materials and any equipment and catalyst at your disposal, describe how you would prepare ammonium nitrate. State conditions under which you can increase the yield in each step.

Anand Jangid

Numerade Educator

Problem 104

As we saw in Section $21.2,$ the reduction of iron oxides is accomplished by using carbon monoxide as a reducing agent. Starting with coke in a blast furnace, the following equilibrium plays a key role in the extraction of iron:
$$\mathrm{C}(s)+\mathrm{CO}_{2}(g) \rightleftharpoons 2 \mathrm{CO}(g)$$
Use the data in Appendix 2 to calculate the equilibrium constant at $25^{\circ} \mathrm{C}$ and $1000^{\circ} \mathrm{C}$. Assume $\Delta H^{\circ}$ and $\Delta S^{\circ}$ to be independent of temperature.

David Collins

Numerade Educator

Problem 105

Assuming ideal behavior, calculate the density of gaseous HF at its normal boiling point $\left(19.5^{\circ} \mathrm{C}\right)$. The experimentally measured density under the same conditions is $3.10 \mathrm{~g} / \mathrm{L}$. Account for the discrepancy between your calculated value and the experimental result.

Arpit Gupta

Numerade Educator

Problem 106

A 10.0 -g sample of white phosphorus was burned in an excess of oxygen. The product was dissolved in enough water to make $500 \mathrm{~mL}$ of solution. Calculate the $\mathrm{pH}$ of the solution at $25^{\circ} \mathrm{C}$.

Arpit Gupta

Numerade Educator