The triatomic molecular ion H3 _ was first detected and characterized by J. J. Thomson

(a) Define the four atomic properties that are reviewed in the Interchapter. (b) To what do the three parts of the electron configuration (nl#) correlate? (c) Which part of the electron configuration is primarily associated with the size of the atom? (d) What is the major distinction between the outer electron configurations within a group and those within a period? (e) What correlation, if any, exists between the group number and the number of valence electrons?

(a) What trends, if any, exist for Zeff across a period and down a group? (b) How does Zeff influence atomic size, IE1, and EN across a period?

Iodine monochloride and elemental bromine have nearly the same molar mass and liquid density but very different boiling points. (a) What molecular property is primarily responsible for this difference in boiling point? What atomic property gives rise to it? Explain. (b) Which substance has a higher boiling point? Why?

How does the trend in atomic size differ from the trend in ionization energy? Explain.

How are bond energy, bond length, and reactivity related for similar compounds?

How are covalent and metallic bonding similar? How are they different?

If the leftmost element in a period combined with each of the others in the period, how would the type of bonding change from left to right? Explain in terms of atomic properties.

Why is rotation about the bond axis possible for singlebonded atoms but not double-bonded atoms?

Explain the horizontal irregularity in size of the most common ions of Period 3 elements.

Is S2_ larger or smaller than Cl_? Is Mg2_ larger or smaller than Na_? Explain.

How do each of the following correlate with the electronegativity of the elements: (a) the type of bonding in element oxides; (b) the acid-base behavior of element oxides?

(a) How does the metallic character of an element correlate with the acidity of its oxide? (b) What trends, if any, exist in oxide basicity across a period and down a group?

How are atomic size, IE1, and EN related to redox behavior of the elements in Groups 1A(1), 2A(2), 6A(16), and 7A(17)?

How do the physical properties of a network covalent solid and a molecular covalent solid differ? Why? (grouped in similar pairs)

Rank the following elements in order of increasing (a) atomic size: Ba, Mg, Sr (b) IE1: P, Na, Al (c) EN: Br, Cl, Se (d) no. of valence electrons: Bi, Ga, Sn

Rank the following elements in order of decreasing (a) atomic size: N, Si, P (b) IE1: Kr, K, Ar (c) EN: In, Rb, I (d) no. of valence electrons: Sb, S, Cs

Which of the following pairs react to form ionic compounds: (a) Cl and Br; (b) Na and Br; (c) P and Se; (d) H and Ba?

Which of the following pairs react to form covalent compounds: (a) Be and C; (b) Sr and O; (c) Ca and Cl; (d) P and F?

Draw a Lewis structure for a compound with a bond order of 2 throughout the molecule.

Draw a Lewis structure for a polyatomic ion with a fractional bond order throughout the molecule.

Rank the following in order of increasing bond length: SiCl4, CF4, GeBr4.

Rank the following in order of decreasing bond energy: NF3, NI3, NCl3.

Rank the following in order of increasing radius: (a) O2_, F_, Na_ (b) S2_, P3_, Cl_

Rank the following in order of decreasing radius: (a) Ca2_, K_, Ga3_ (b) Br_, Sr2_, Rb_

Rank O_, O2_, and O in order of increasing size.

Rank Tl3_, Tl, and Tl_ in order of decreasing size.

Which member of each pair gives the more basic solution in water: (a) CaO or SO3; (b) BeO or BaO; (c) CO2 or SO2; (d) P4O10 or K2O? For the pair in part (a), write an equation for the dissolving of each oxide to support your answer.

Which member of each pair gives the more acidic solution in water: (a) CO2 or SrO; (b) SnO or SnO2; (c) Cl2O or Na2O; (d) SO2 or MgO? For the pair in part (a), write an equation for the dissolving of each oxide to support your answer.

Which member of each pair has more covalent character in its bonds: (a) LiCl or KCl; (b) AlCl3 or PCl3; (c) NCl3 or AsCl3?

Which member of each pair has more ionic character in its bonds: (a) BeF2 or CaF2; (b) PbF2 or PbF4; (c) GeF4 or PF3?

Rank the following in order of increasing (a) Melting point: Na, Si, Ar (b) _Hfus: Rb, Cs, Li

Rank the following in order of decreasing (a) Boiling point: O2, Br2, As(s) (b) _Hvap: Cl2, Ar, I2

Hydrogen has only one proton, but its IE1 is much greater than that of lithium, which has three protons. Explain.

Sketch a periodic table, and label the areas containing elements that give rise to the three types of hydrides. (grouped in similar pairs)

Draw Lewis structures for the following compounds, and predict which member of each pair will form hydrogen bonds: (a) NF3 or NH3 (b) CH3OCH3 or CH3CH2OH

Draw Lewis structures for the following compounds, and predict which member of each pair will form hydrogen bonds: (a) NH3 or AsH3 (b) CH4 or H2O

Complete and balance the following equations: (a) An active metal reacting with acid, (b) A saltlike (alkali metal) hydride reacting with water,

Complete and balance the following equations: (a) A saltlike (alkaline earth metal) hydride reacting with water, (b) Reduction of a metal halide by hydrogen to form a metal,

Compounds such as NaBH4, Al(BH4)3, and LiAlH4 are complex hydrides used as reducing agents in many syntheses. (a) Give the oxidation state of each element in these compounds. (b) Write a Lewis structure for the polyatomic anion in NaBH4, and predict its shape.

Unlike the F_ ion, which has an ionic radius close to 133 pm in all alkali metal fluorides, the ionic radius of H_ varies from 137 pm in LiH to 152 pm in CsH. Suggest an explanation for the large variability in the size of H_ but not F_.

How does the maximum oxidation number vary across a period in the main groups? Is the pattern in Period 2 different?

What correlation, if any, exists for the Period 2 elements between group number and the number of covalent bonds the element typically forms? How is the correlation different for elements in Periods 3 to 6?

Each of the chemically active Period 2 elements forms stable compounds that have bonds to fluorine. (a) What are the names and formulas of these compounds? (b) Does _EN increase or decrease left to right across the period? (c) Does percent ionic character increase or decrease left to right? (d) Draw Lewis structures for these compounds. PdCl2(aq) _ H2(g) CaH2(s) _ H2O(l) LiH(s) _ H2O(l) Al(s) _ HCl(aq)

Period 6 is unusual in several ways. (a) It is the longest period in the table. How many elements belong to Period 6? How many metals? (b) It contains no metalloids. Where is the metal/nonmetal boundary in Period 6?

An element forms an oxide, E2O3, and a fluoride, EF3. (a) Of which two groups might E be a member? (b) How does the group to which E belongs affect the properties of the oxide and the fluoride?

Fluorine lies between oxygen and neon in Period 2. Whereas atomic sizes and ionization energies of these three elements change smoothly, their electronegativities display a dramatic change. What is this change, and how do their electron configurations explain it?

Lithium salts are often much less soluble in water than the corresponding salts of other alkali metals. For example, at 18_C, the concentration of a saturated LiF solution is 1.0_10_2 M, whereas that of a saturated KF solution is 1.6 M. How would you explain this behavior?

The alkali metals play virtually the same general chemical role in all their reactions. (a) What is this role? (b) How is it based on atomic properties? (c) Using sodium, write two balanced equations that illustrate this role.

How do atomic properties account for the low densities of the Group 1A(1) elements? (grouped in similar pairs)

Each of the following properties shows a regular trend in Group 1A(1). Predict whether each increases or decreases down the group: (a) density; (b) ionic size; (c) E E bond energy; (d) IE1; (e) magnitude of _Hhydr of E_ ion.

Each of the following properties shows a regular trend in Group 1A(1). Predict whether each increases or decreases up the group: (a) melting point; (b) E E bond length; (c) hardness; (d) molar volume; (e) lattice energy of EBr.

Write a balanced equation for the formation from its elements of sodium peroxide, an industrial bleach.

Write a balanced equation for the formation of rubidium bromide through a reaction of a strong acid and a strong base.

Although the alkali metal halides can be prepared directly from the elements, the far less expensive industrial route is treatment of the carbonate or hydroxide with aqueous hydrohalic acid (HX) followed by recrystallization. Balance the reaction between potassium carbonate and aqueous hydriodic acid.

Lithium forms several useful organolithium compounds. Calculate the mass percent of Li in the following: (a) Lithium stearate (C17H35COOLi), a water-resistant grease used in cars because it does not harden at cold temperatures (b) Butyllithium (LiC4H9), a reagent in organic syntheses

How do Groups 1A(1) and 2A(2) compare with respect to reaction of the metals with water?

Alkaline earth metals are involved in two key diagonal relationships in the periodic table. (a) Give the two pairs of elements in these diagonal relationships. (b) For each pair, cite two similarities that demonstrate the relationship. (c) Why are the members of each pair so similar in behavior?

The melting points of alkaline earth metals are many times higher than those of the alkali metals. Explain this difference on the basis of atomic properties. Name three other physical properties for which Group 2A(2) metals have higher values than the corresponding 1A(1) metals. (grouped in similar pairs)

Write a balanced equation for each reaction: (a) Slaking of lime (treatment with water) (b) Combustion of calcium in air

Write a balanced equation for each reaction: (a) Thermal decomposition of witherite (barium carbonate) (b) Neutralization of stomach acid (HCl) by milk of magnesia (magnesium hydroxide)

Lime (CaO) is one of the most abundantly produced chemicals in the world. Write balanced equations for (a) The preparation of lime from natural sources (b) The use of slaked lime to remove SO2 from flue gases (c) The reaction of lime with arsenic acid (H3AsO4) to manufacture the insecticide calcium arsenate (d) The regeneration of NaOH in the paper industry by reaction of lime with aqueous sodium carbonate

In some reactions, Be behaves like a typical alkaline earth metal; in others, it does not. Complete and balance the following equations: (a) BeO(s) _ H2O(l) (b) BeCl2(l) _ Cl_(l; from molten NaCl) In which reaction does Be behave like the other Group 2A(2) members?

How do the transition metals in Period 4 affect the pattern of ionization energies in Group 3A(13)? How does this pattern compare with that in Group 3B(3)?

How do the acidities of aqueous solutions of Tl2O and Tl2O3 compare with each other? Explain.

Despite the expected decrease in atomic size, there is an unexpected drop in the first ionization energy between Groups 2A(2) and 3A(13) in Periods 2 through 4. Explain this pattern in terms of electron configurations and orbital energies.

Many compounds of Group 3A(13) elements have chemical behavior that reflects an electron deficiency. (a) What is the meaning of electron deficiency? (b) Give two reactions that illustrate this behavior.

Borons chemistry is not typical of its group. (a) Cite three ways in which boron and its compounds differ significantly from the other 3A(13) members and their compounds. (b) What is the reason for these differences? (grouped in similar pairs)

Rank the following oxides in order of increasing aqueous acidity: Ga2O3, Al2O3, In2O3.

Rank the following hydroxides in order of increasing aqueous basicity: Al(OH)3, B(OH)3, In(OH)3.

Thallium forms the compound TlI3. What is the apparent oxidation state of Tl in this compound? Given that the anion is I3 _, what is the actual oxidation state of Tl? Draw the shape of the anion, giving its VSEPR class and bond angles. Propose a reason why the compound does not exist as (Tl3_)(I_)3.

Very stable dihalides of the Group 3A(13) metals are known. What is the apparent oxidation state of Ga in GaCl2? Given that GaCl2 consists of a Ga_ cation and a GaCl4 _ anion, what are the actual oxidation states of Ga? Draw the shape of the anion, giving its VSEPR class and bond angles.

Give the name and symbol or formula of a Group 3A(13) element or compound that fits each description or use: (a) Component of heat-resistant (Pyrex-type) glass (b) Manufacture of high-speed computer chips (c) Largest temperature range for liquid state of an element (d) Elemental substance with three-center, two-electron bonds (e) Metal protected from oxidation by adherent oxide coat (f) Mild antibacterial agent (e.g., for eye infections) (g) Toxic metal that lies between two other toxic metals

Indium (In) reacts with HCl to form a diamagnetic solid with the formula InCl2. (a) Write condensed electron configurations for In, In_, In2_, and In3_. (b) Which of these species is (are) diamagnetic and which paramagnetic? (c) What is the apparent oxidation state of In in InCl2? (d) Given your answers to parts (b) and (c), explain how InCl2 can be diamagnetic.

Use VSEPR theory to draw structures, with ideal bond angles, for boric acid and the anion it forms in reaction with water.

Boron nitride (BN) has a structure similar to graphite, but is a white insulator rather than a black conductor. It is synthesized by heating diboron trioxide with ammonia at about 1000oC. (a) Write a balanced equation for the formation of BN; water forms also. (b) Calculate _H_rxn for the production of BN (_H_f of BN is _254 kJ/mol). (c) Boron is obtained from the mineral borax, Na2B4O7 10H2O. How much borax is needed to produce 1.0 kg of BN, assuming 72% yield?

How does the basicity of SnO2 in water compare with that of CO2? Explain.

Nearly every compound of silicon has the element in the _4 oxidation state. In contrast, most compounds of lead have the element in the _2 state. (a) What general observation do these facts illustrate? (b) Explain in terms of atomic and molecular properties. (c) Give an analogous example from Group 3A(13).

The sum of IE1 through IE4 for Group 4A(14) elements shows a decrease from C to Si, a slight increase from Si to Ge, a decrease from Ge to Sn, and an increase from Sn to Pb. (a) What is the expected trend for IEs down a group? (b) Suggest a reason for the deviations in Group 4A(14). (c) Which group might show even greater deviations?

Give explanations for the large drops in melting point from C to Si and from Ge to Sn.

What is an allotrope? Name two Group 4A(14) elements that exhibit allotropism, and identify two of their allotropes.

Even though EN values vary relatively little down Group 4A(14), the elements change from nonmetal to metal. Explain.

How do atomic properties account for the enormous number of carbon compounds? Why dont other Group 4A(14) elements behave similarly? (grouped in similar pairs)

Draw a Lewis structure for (a) The cyclic silicate ion Si4O12 8_ (b) A cyclic hydrocarbon with formula C4H8

Draw a Lewis structure for (a) The cyclic silicate ion Si6O18 12_ (b) A cyclic hydrocarbon with formula C6H12

Show three units of a linear silicone polymer made from (CH3)2Si(OH)2 with some (CH3)3SiOH added to end the chain.

Show two chains of three units each of a sheet silicone polymer made from (CH3)2Si(OH)2 with CH3Si(OH)3 added to crosslink the chains.

Zeolite A, Na12[(AlO2)12(SiO2)12] 27H2O, is used to soften water by replacing Ca2_ and Mg2_ with Na_. Hard water from a certain source is 4.5_10_3 M Ca2_ and 9.2_10_4 M Mg2_, and a pipe delivers 25,000 L of this hard water per day. What mass (in kg) of zeolite A is needed to soften a weeks supply of the water? (Assume zeolite A loses its capacity to exchange ions when 85 mol % of its Na_ has been lost.)

Give the name and symbol or formula of a Group 4A(14) element or compound that fits each description or use: (a) Hardest known natural substance (b) Medicinal antacid (c) Atmospheric gas implicated in the greenhouse effect (d) Waterproofing polymer based on silicon (e) Synthetic abrasive composed entirely of elements in the group (f) Product formed when coke burns in a limited supply of air (g) Toxic metal found in plumbing and paints

One similarity between B and Si is the explosive combustion of their hydrides in air. Write balanced equations for the combustion of B2H6 and of Si4H10.

Which Group 5A(15) elements form trihalides? Pentahalides? Explain.

As you move down Group 5A(15), the melting points of the elements increase and then decrease. Explain.

(a) What is the range of oxidation states shown by the elements of Group 5A(15) as you move down the group? (b) How does this range illustrate the general rule for the range of oxidation states in groups on the right side of the periodic table?

Bismuth(V) compounds are such powerful oxidizing agents that they have not been prepared in pure form. How is this fact consistent with the location of Bi in the periodic table?

Rank the following oxides in order of increasing acidity in water: Sb2O3, Bi2O3, P4O10, Sb2O5. (grouped in similar pairs)

Assuming acid strength relates directly to electronegativity of the central atom, rank H3PO4, HNO3, and H3AsO4 in order of increasing acid strength. _

Assuming acid strength relates directly to number of O atoms bonded to the central atom, rank H2N2O2 [or (HON)2]; HNO3 (or HONO2); and HNO2 (or HONO) in order of decreasing acid strength.

Complete and balance the following: (a) As(s) _ excess O2(g) (b) Bi(s) _ excess F2(g) (c) Ca3As2(s) _ H2O(l)

Complete and balance the following: (a) Excess Sb(s) _ Br2(l) (b) HNO3(aq) _ MgCO3(s) (c) K2HPO4(s)

Complete and balance the following: (a) N2(g) _Al(s) (b) PF5(g) _ H2O(l)

Complete and balance the following: (a) AsCl3(l) _ H2O(l) (b) Sb2O3(s) _ NaOH(aq)

Based on the relative sizes of F and Cl, predict the structure of PF2Cl3.

Use the VSEPR model to predict the structure of the cyclic ion P3O9 3_.

The pentafluorides of the larger members of Group 5A(15) have been prepared, but N can have only eight electrons. Aclaim has been made that, at low temperatures, a compound with the empirical formula NF5 forms. Draw a possible Lewis structure for this compound. (Hint: NF5 is ionic.)

Give the name and symbol or formula of a Group 5A(15) element or compound that fits each description or use: (a) Hydride produced at multimillion-ton level (b) Element(s) essential in plant nutrition (c) Hydride used to manufacture rocket propellants and drugs (d) Odd-electron molecule (two examples) (e) Amphoteric hydroxide with a 5A element in its _3 state (f) Phosphorus-containing water softener (g) Element that is an electrical conductor

In addition to those in Table 14.3, other less stable nitrogen oxides exist. Draw a Lewis structure for each of the following: (a) N2O2, a dimer of nitrogen monoxide with an N N bond (b) N2O2, a dimer of nitrogen monoxide with no N N bond (c) N2O3 with no N N bond (d) NO_ and NO3 _, products of the ionization of liquid N2O4

Nitrous oxide (N2O), the laughing gas used as an anesthetic by dentists, is made by thermal decomposition of solid NH4NO3. Write a balanced equation for this reaction. What are the oxidation states of N in NH4NO3 and in N2O?

Write balanced equations for the thermal decomposition of potassium nitrate (O2 is also formed in both cases): (a) at low temperature to the nitrite; (b) at high temperature to the metal oxide and nitrogen.

Rank the following in order of increasing electrical conductivity, and explain your ranking: Po, S, Se.

The oxygen and nitrogen families have some obvious similarities and differences. (a) State two general physical similarities between Group 5A(15) and 6A(16) elements. (b) State two general chemical similarities between Group 5A(15) and 6A(16) elements. (c) State two chemical similarities between P and S. (d) State two physical similarities between N and O. (e) State two chemical differences between N and O.

A molecular property of the Group 6A(16) hydrides changes abruptly down the group. This change has been explained in terms of a change in orbital hybridization. (a) Between what periods does the change occur? (b) What is the change in the molecular property? (c) What is the change in hybridization? (d) What other group displays a similar change? (grouped in similar pairs)

Complete and balance the following: (a) NaHSO4(aq) _ NaOH(aq) (b) S8(s) _ excess F2(g) (c) FeS(s) _ HCl(aq) (d) Te(s) _ I2(s)

Complete and balance the following: (a) H2S(g) _ O2(g) (b) SO3(g) _ H2O(l) (c) SF4(g) _ H2O(l) (d) Al2Se3(s) _ H2O(l)

Is each oxide basic, acidic, or amphoteric in water: (a) SeO2; (b) N2O3; (c) K2O; (d) BeO; (e) BaO?

Is each oxide basic, acidic, or amphoteric in water: (a) MgO; (b) N2O5; (c) CaO; (d) CO2; (e) TeO2?

Rank the following hydrides in order of increasing acid strength: H2S, H2O, H2Te.

Rank the following species in order of decreasing acid strength: H2SO4, H2SO3, HSO3 _.

Describe the physical changes observed when solid sulfur is heated from room temperature to 440_C and then poured quickly into cold water. Explain the molecular changes responsible for the macroscopic changes.

Give the name and symbol or formula of a Group 6A(16) element or compound that fits each description or use: (a) Unreactive gas used as an electrical insulator (b) Unstable allotrope of oxygen (c) Oxide having sulfur with the same O.N. as in sulfuric acid (d) Air pollutant produced by burning sulfur-containing coal (e) Powerful dehydrating agent (f) Compound used in solution in the photographic process (g) Gas in trace amounts in air that tarnishes silver

Give the oxidation state of sulfur in (a) S8; (b) SF4; (c) SF6; (d) H2S; (e) FeS2; (f) H2SO4; (g) Na2S2O3 5H2O.

Disulfur decafluoride is intermediate in reactivity between SF4 and SF6. It disproportionates at 150_C to these monosulfur fluorides. Write a balanced equation for this reaction, and give the oxidation state of S in each compound.

(a) Give the physical state and color of each halogen at STP. (b) Explain the change in physical state down Group 7A(17) in terms of molecular properties. _

(a) What are the common oxidation states of the halogens? (b) Give an explanation based on electron configuration for the range and values of the oxidation states of chlorine. (c) Why is fluorine an exception to the pattern of oxidation states found for the other group members?

How many electrons does a halogen atom need to complete its octet? Give examples of the ways a Cl atom can do so.

Select the stronger bond in each pair: (a) Cl Cl or Br Br (b) Br Br or I I (c) F F or Cl Cl. Why doesnt the F F bond strength follow the group trend?

In addition to interhalogen compounds, many interhalogen ions exist. Would you expect interhalogen ions with a 1_ or a 1_ charge to have an even or odd number of atoms? Explain.

(a) A halogen (X2) disproportionates in base in several steps to X_ and XO3 _. Write the overall equation for the disproportionation of Br2 to Br_ and BrO3 _. (b) Write a balanced equation for the reaction of ClF5 with aqueous base (see the reaction of BrF5 shown on p. 614). (grouped in similar pairs)

Complete and balance the following equations. If no reaction occurs, write NR: (a) Rb(s) _ Br2(l) (b) I2(s) _ H2O(l ) (c) Br2(l) _ I_(aq) (d) CaF2(s) _ H2SO4(l)

Complete and balance the following equations. If no reaction occurs, write NR: (a) H3PO4(l ) _ NaI(s) (b) Cl2(g) _ I_(aq) (c) Br2(l ) _ Cl_(aq) (d) ClF(g) _ F2(g)

Rank the following acids in order of increasing acid strength: HClO, HClO2, HBrO, HIO.

Rank the following acids in order of decreasing acid strength: HBrO3, HBrO4, HIO3, HClO4.

Give the name and symbol or formula of a Group 7A(17) element or compound that fits each description or use: (a) Used in etching glass (b) Naturally occurring source (ore) of fluorine (c) Oxide used in bleaching paper pulp and textiles (d) Weakest hydrohalic acid (e) Compound used to prevent goiter (thyroid disorder) (f) Element that is produced in the largest quantity (g) Organic chloride used to make plastics

An industrial chemist treats solid NaCl with concentrated H2SO4 and obtains gaseous HCl and NaHSO4. When she substitutes solid NaI for NaCl, gaseous H2S, solid I2, and S8 are obtained but no HI. (a) What type of reaction did the H2SO4 undergo with NaI? (b) Why does NaI, but not NaCl, cause this type of reaction? (c) To produce HI(g) by the reaction of NaI with an acid, how does the acid have to differ from sulfuric acid?

Rank the halogens Cl2, Br2, and I2 in order of increasing oxidizing strength based on their products with metallic Re: ReCl6, ReBr5, ReI4. Explain your ranking.

Which noble gas is the most abundant in the universe? In Earths atmosphere?

What oxidation states does Xe show in its compounds?

Why do the noble gases have such low boiling points?

Explain why Xe, and to a limited extent Kr, form compounds, whereas He, Ne, and Ar do not.

(a) Why do stable xenon fluorides have an even number of F atoms? (b) Why do the ionic species XeF3 _ and XeF7 _ have odd numbers of F atoms? (c) Predict the shape of XeF3 _.

Xenon tetrafluoride reacts with antimony pentafluoride to form the following ionic complex: [XeF3]_ [SbF6]_. (a) Which of the following illustrates the molecular shapes of the reactants and product? (b) How, if at all, does the hybridization of xenon change in the reaction?

Given the following information, calculate the heat of solution of the hydronium ion:

The electronic transition in Na from 3p1 to 3s1 gives rise to a bright yellow-orange emission at 589.2 nm. What is the energy of this transition?

Unlike other Group 2A(2) metals, beryllium reacts like aluminum and zinc with concentrated aqueous base to release hydrogen gas and form oxoanions of formula M(OH)4 n_. Write equations for the reactions of these three metals with NaOH.

The interhalogen IF undergoes the reaction depicted below (I is purple and F is green): (a) Write the balanced equation. (b) Name the interhalogen product. (c) What type of reaction is shown? (d) If each molecule of IF represents 2.50_10_3 mol, what mass of each product forms?

Cyclopropane (C3H6), the smallest cyclic hydrocarbon, is reactive for the same reason white phosphorus is. Use bond properties and valence bond theory to explain its high reactivity.

Thionyl chloride (SOCl2) is a sulfur oxohalide used industrially to dehydrate metal halide hydrates. (a) Write a balanced equation for its reaction with magnesium chloride hexahydrate, in which SO2 and HCl form along with the metal halide. (b) Draw a Lewis structure of SOCl2 with minimal formal charges.

The main reason alkali metal dihalides (MX2) do not form is the high IE2 of the metal. (a) Why is IE2 so high for alkali metals? (b) The IE2 for Cs is 2255 kJ/mol, low enough for CsF2 to form exothermically (_H_f _ _125 kJ/mol). This compound cannot be synthesized, however, because CsF forms with a much greater release of heat (_H_f _ _530 kJ/mol). Thus, the breakdown of CsF2 to CsF happens readily. Write the equation for this breakdown, and calculate the heat of reaction per mole of CsF.

Semiconductors made from elements in Groups 3A(13) and 5A(15) are typically prepared by direct reaction of the elements at high temperature. An engineer treats 32.5 g of molten gallium with 20.4 L of white phosphorus vapor at 515 K and 195 kPa. If purification losses are 7.2% by mass, how many grams of gallium phosphide will be prepared?

Two substances with empirical formula HNO are hyponitrous acid ( _ 62.04 g /mol) and nitroxyl ( _ 31.02 g/mol). (a) What is the molecular formula of each species? (b) For each species, draw the Lewis structure having the lowest formal charges. (Hint: Hyponitrous acid has an N N bond.) (c) Predict the shape around the N atoms of each species. (d) When hyponitrous acid loses two protons, it forms the hyponitrite ion. Draw cis and trans forms of this ion.

The species CO, CN_, and C2 2_ are isoelectronic. (a) Draw their Lewis structures. (b) Draw their MO diagrams (assume 2s-2p mixing, as in N2), and give the bond order and electron configuration for each.

The Ostwald process is a series of three reactions used for the industrial production of nitric acid from ammonia. (a) Write a series of balanced equations for the Ostwald process. (b) If NO is not recycled, how many moles of NH3 are consumed per mole of HNO3 produced? (c) In a typical industrial unit, the process is very efficient, with a 96% yield for the first step. Assuming 100% yields for the subsequent steps, what volume of concentrated aqueous nitric acid (60.% by mass; d _ 1.37 g/mL) can be prepared for each cubic meter of a gas mixture that is 90.% air and 10.% NH3 by volume at the industrial conditions of 5.0 atm and 850._C?

Buckminsterfullerene (C60) is a soccer-ballshaped molecule with a C atom at each vertex. It crystallizes in a facecentered cubic unit cell that contains 240 C atoms and has a density of only 1.693 g/cm3, less than half that of diamond. Calculate the volume and edge length of the unit cell, and suggest a reason for the low density despite the closest packing.

Perhaps surprisingly, some pure liquid interhalogens that contain fluorine have high electrical conductivity. The explanation is that one molecule transfers a fluoride ion to another molecule. Write the equation that would explain the high electrical conductivity of bromine trifluoride.

All common plant fertilizers contain nitrogen compounds. Determine the mass % of N in (a) ammonia; (b) ammonium nitrate; (c) ammonium hydrogen phosphate.

Producer gas is a fuel formed by passing air over red-hot coke (amorphous carbon). What mass of a producer gas that consists of 25% CO, 5.0% CO2, and 70.% N2 by mass can be formed from 1.75 metric tons of coke, assuming an 87% yield?

Gaseous F2 reacts with water to form HF and O2. In NaOH solution, F2 forms F_, water, and oxygen difluoride (OF2), a highly toxic gas and powerful oxidizing agent. The OF2 reacts with excess OH_, forming O2, water, and F_. (a) For each reaction, write a balanced equation, give the oxidation state of O in all compounds, and identify the oxidizing and reducing agents. (b) Draw a Lewis structure for OF2, and predict its shape.

What is a disproportionation reaction, and which of the following fit the description? (a) I2(s) _ KI(aq) KI3(aq) (b) 2ClO2(g) _ H2O(l) HClO3(aq) _ HClO2(aq) (c) Cl2(g) _ 2NaOH(aq) NaCl(aq) _ NaClO(aq) _ H2O(l) (d) NH4NO2(s) N2(g) _ 2H2O(g) (e) 3MnO4 2_(aq) _ 2H2O(l) 2MnO4 _(aq) _ MnO2(s) _ 4OH_(aq) (f) 3AuCl(s) AuCl3(s) _ 2Au(s)

Explain the following observations: (a) In reactions with Cl2, phosphorus forms PCl5 in addition to the expected PCl3, but nitrogen forms only NCl3. (b) Carbon tetrachloride is unreactive toward water, but silicon tetrachloride reacts rapidly and completely. (To give what?) (c) The sulfur-oxygen bond in SO4 2_ is shorter than expected for an S O single bond. (d) Chlorine forms ClF3 and ClF5, but ClF4 is unknown.

Which group(s) of the periodic table is (are) described by each of the following general statements? (a) The elements form compounds of VSEPR class AX3E. (b) The free elements are strong oxidizing agents and form monatomic ions and oxoanions. (c) The atoms form compounds by combining with two other atoms that donate one electron each. (d) The free elements are strong reducing agents, show only one nonzero oxidation state, and form mainly ionic compounds. (e) The elements can form stable compounds with only three bonds, but as a central atom, they can accept a pair of electrons from a fourth atom without expanding their valence shell. (f) Only larger members of the group are chemically active.

Diiodine pentaoxide (I2O5) was discovered by Joseph Gay-Lussac in 1813, but its structure was unknown until 1970! Like Cl2O7, it can be prepared by the dehydration-condensation of the corresponding oxoacid. (a) Name the precursor oxoacid, write a reaction for formation of the oxide, and draw a likely Lewis structure. (b) Data show that the bonds to the terminal O are shorter than the bonds to the bridging O. Why? (c) I2O5 is one of the few chemicals that can oxidize CO rapidly and completely; elemental iodine forms in the process. Write a balanced equation for this reaction.

An important starting material for the manufacture of polyphosphazenes is the cyclic molecule (NPCl2)3. The molecule has a symmetrical six-membered ring of alternating N and P atoms, with the Cl atoms bonded to the P atoms. The nitrogenphosphorus bond length is significantly less than that expected for an N P single bond. (a) Draw a likely Lewis structure for the molecule. (b) How many lone pairs of electrons do the ring atoms have? (c) What is the order of the nitrogen-phosphorus bond?

Potassium fluotitanate (K2TiF6), a starting material for producing other titanium salts, is made by dissolving titanium(IV) oxide in concentrated HF, adding aqueous KF, and then heating to dryness to drive off excess HF. The impure solid is recrystallized by dissolving in hot water and then cooling to 0_C, which leaves excess KF in solution. For the reaction of 5.00 g of TiO2, 250. mL of hot water is used to recrystallize the product. How many grams of purified K2TiF6 are obtained? (Solubility of K2TiF6 in water at 0_C is 0.60 g/100 mL.)

Bromine monofluoride (BrF) disproportionates to bromine gas and bromine tri- and pentafluorides. Use the following to find _H_rxn for the decomposition of BrF to its elements:

Account for the following facts: (a) Ca2_ and Na_ have very nearly the same radii. (b) CaF2 is insoluble in water, but NaF is quite soluble. (c) Molten BeCl2 is a poor electrical conductor, whereas molten CaCl2 is an excellent one.

Cake alum (aluminum sulfate) is used as a flocculating agent in water purification. The floc is a gelatinous precipitate of aluminum hydroxide that carries small suspended particles and bacteria out of solution for removal by filtration. (a) The hydroxide is formed by the reaction of the aluminum ion with water. Write the equation for this reaction. (b) The acidity from this reaction is partially neutralized by the sulfate ion. Write an equation for this reaction.

Carbon tetrachloride is made by passing Cl2 in the presence of a catalyst through liquid CS2 near its boiling point. Disulfur dichloride (S2Cl2) also forms, in addition to the byproducts SCl2 and CCl3SCl. How many grams of CS2 reacted if excess Cl2 yielded 50.0 g of CCl4 and 0.500 g of CCl3SCl? Is it possible to determine how much S2Cl2 and SCl2 also formed? Explain.

H2 may act as a reducing agent or an oxidizing agent, depending on the substance reacting with it. Using, in turn, sodium or chlorine as the other reactant, write balanced equations for the two reactions, and characterize the redox role of hydrogen.

P4 is prepared by heating phosphate rock [principally Ca3(PO4)2] with sand and coke: ] How many kilograms of phosphate rock are needed to produce 315 mol of P4, assuming that the conversion is 90.% efficient?

Element E forms an oxide of general structure A and a chloride of general structure B: For the anion EF5 _, what is (a) the molecular shape; (b) the hybridization of E; (c) the O.N. of E?

From its formula, one might expect CO to be quite polar, but its dipole moment is actually low (0.11 D). (a) Draw the Lewis structure for CO. (b) Calculate the formal charges. (c) Based on your answers to parts (a) and (b), explain why the dipole moment is so low.

In addition to Al2Cl6, aluminum forms other species with bridging halide ions to two aluminum atoms. One such species is the ion Al2Cl7 _. The ion is symmetrical, with a 180_ Al Cl Al bond angle. (a) What orbitals does Al use to bond with the Cl atoms? (b) What is the shape around each Al? (c) What is the hybridization of the central Cl? (d) What do the shape and hybridization suggest about the presence of lone pairs of electrons on the central Cl?

When an alkaline earth carbonate is heated, it releases CO2, leaving the metal oxide. The temperature at which each Group 2A(2) carbonate yields a CO2 partial pressure of 1 atm is Carbonate Temperature (_C) MgCO3 542 CaCO3 882 SrCO3 1155 BaCO3 1360 (a) Suggest a reason for this trend. (b) Mixtures of CaCO3 and MgO are used to absorb dissolved silicates from boiler water. How would you prepare a mixture of CaCO3 and MgO from dolomite, which contains CaCO3 and MgCO3?

The bond angles in the nitrite ion, nitrogen dioxide, and the nitronium ion (NO2 _) are 115_, 134_, and 180_, respectively. Explain these values using Lewis structures and VSEPR theory.

A common method for producing a gaseous hydride is to treat a salt containing the anion of the volatile hydride with a strong acid. (a) Write an equation for each of the following examples: (1) the production of HF from CaF2; (2) the production of HCl from NaCl; (3) the production of H2S from FeS. (b) In some cases even a weak acid such as water will suffice if the anion of the salt has a sufficiently strong attraction for protons. An example is the production of PH3 from Ca3P2 and water. Write the equation for this reaction. (c) By analogy, predict the products and write the equation for the reaction of Al4C3 with water.

Chlorine trifluoride was formerly used in the production of uranium hexafluoride for the U.S. nuclear industry: How many grams of UF6 can form from 1.00 metric ton of uranium ore that is 1.55% by mass uranium and 12.75 L of chlorine trifluoride (d _ 1.88 g/mL)?

Chlorine is used to make bleach solutions containing 5.25% NaClO (by mass). Assuming 100% yield in the reaction producing NaClO from Cl2, how many liters of Cl2(g) at STP will be needed to make 1000. L of bleach solution (d _ 1.07 g/mL)?

The triatomic molecular ion H3 _ was first detected and characterized by J. J. Thomson using mass spectrometry. Use the bond energy of H2 (432 kJ/mol) and the proton affinity of H2 (H2 _ H_ H3 _; _H__337 kJ/mol) to calculate the heat of reaction for

An atomic hydrogen torch is used for cutting and welding thick sheets of metal. When H2 passes through an electric arc, the molecules decompose into atoms, which react with O2 at the end of the torch. Temperatures in excess of 5000_C are reached, which can melt all metals. Write equations for the breakdown of H2 to H atoms and for the subsequent overall reaction of the H atoms with oxygen. Use Appendix B to find the standard heat of each reaction per mole of product.

In aqueous hydrogen fluoride solution, an important species is the ion HF2 _, which has the bonding arrangement FHF_. Draw the Lewis structure for this ion, and explain how it arises.

Which of the following oxygen ions are paramagnetic: O_, O_, O2_, O2_?

Copper(II) hydrogen arsenite (CuHAsO3) is a green pigment once used in wallpaper. In damp conditions, mold metabolizes this compound to trimethylarsine [(CH3)3As], a highly toxic gas. (a) Calculate the mass percent of As in each compound. (b) How much CuHAsO3 must react to reach a toxic level in a room that measures 12.35 m _ 7.52 m _ 2.98 m (arsenic is toxic at 0.50 mg/m3)?

Hydrogen peroxide can act as either an oxidizing agent or a reducing agent. (a) When H2O2 is treated with aqueous KI, I2 forms. In which role is H2O2 acting? What is the oxygencontaining product formed? (b) When H2O2 is treated with aqueous KMnO4, the purple color of MnO4 _ disappears and a gas forms. In which role is H2O2 acting? What is the oxygencontaining product formed?