Ch 24 - 30E

Problem 44E

Problem 45E

Problem 48E

Problem 46E

Problem 49E

Problem 50E

Problem 51E

Problem 53E What structural feature do hemoglobin, cytochrome c, and chlorophyll have in common? Step-by-step solution

Problem 54E Identify the central metal atom in each complex. a. hemoglobin b. carbonic anhydrase c. chlorophyll d. iron blue

Problem 56E

Problem 57

Problem 58E

Problem 59E Draw the Lewis diagrams for each ligand. Indicate the lone pair(s) that may be donated to the metal. Indicate any you expect to be bidentate or polydentate. a. NH3 b. SCN- c. H2O

Problem 60E

Problem 61E List all the different formulas for an octahedral complex made from a metal (M) and three different ligands (A, B, and C). Describe any isomers for each complex.

Problem 62E Amino acids, such as glycine (gly), form complexes with the trace metal ions found in the bloodstream. Glycine, whose structure is shown here, acts as a bidentate ligand coordinating with the nitrogen atom and one of the oxygen atoms.

Problem 66E Determine the color and approximate wavelength absorbed most strongly by each solution. a. blue solution b. red solution c. yellow solution

Problem 78E Two ligands, A and B, both form complexes with a particular metal ion. When the metal ion complexes with ligand A, the solution is green. When the metal ion complexes with ligand B, the solution is violet. Which of the two ligands results in the largest ?

Problem 65E Hexacyanomanganate(lll) ion is a low-spin complex. Draw the crystal field splitting diagram with electrons filled in appropriately. Is this complex paramagnetic or diamagnetic?

Problem 64E W, X, Y, and Z are different monodentate ligands. a. Is the square planar [NiWXYZ]2+ optically active? b. Is the tetrahedral [ZnWXYZ]2+ optically active?

Describe reactions that are characteristic of alkanes, alkenes, and alkynes.

What factor determines whether a carbon atom in a compound is chiral?

Give examples of a chiral substituted alkane and an achiral substituted alkane.

Draw all possible structural isomers for the following alkane: C7H16.

How many distinct chloropentanes, C5H11Cl, could be produced in the direct chlorination of n- pentane, CH3(CH2)3CH3? Draw the structure of each molecule.

Draw all possible isomers for the molecule C4H8.

Draw all possible isomers for the molecule C3H5Br.

The structural isomers of pentane, C5H12, have quite different boiling points (see Example 24.1). Explain the observed variation in boiling point, in terms of structure.

Discuss how you can determine which of the following compounds might be alkanes, cycloalkanes, alkenes, or alkynes, without drawing their formulas: (a) C6H12, (b) C4H6, (c) C5H12, (d) C7H14, (e) C3H4.

Draw the structures of cis-2-butene and trans-2-butene. Which of the two compounds would have the higher heat of hydrogenation? Explain.

Would you expect cyclobutadiene to be a stable molecule? Explain. HHCOC B EH B HECOCHH

How many different isomers can be derived from ethylene if two hydrogen atoms are replaced by a fluorine atom and a chlorine atom? Draw their structures and name them. Indicate which are structural isomers and which are geometric isomers.

Suggest two chemical tests that would help you distinguish between these two compounds: (a) CH3CH2CH2CH2CH3 (b) CH3CH2CH2CHCH2

Sulfuric acid (H2SO4) adds to the double bond of alkenes as H1 and 2OSO3H. Predict the products when sulfuric acid reacts with (a) ethylene and (b) propene

Acetylene is an unstable compound. It has a tendency to form benzene as follows: 3C2H2(g) C6H6(l) Calculate the standard enthalpy change in kilojoules per mole for this reaction at 25C.

Predict products when HBr is added to (a) 1-butene and (b) 2-butene

Geometric isomers are not restricted to compounds containing the CC bond. For example, certain disubstituted cycloalkanes can exist in the cis and the trans forms. Label the following molecules as the cis and trans isomer, of the same compound: (a) (b) H A A H H A A H Cl A A H Cl A A H H A A Cl Cl A A H

Which of the following amino acids are chiral: (a) CH3CH(NH2)COOH, (b) CH2(NH2)COOH, (c) CH2(OH)CH(NH2)COOH?

Name the following compounds: CH3OCHOCH2OCH2OCH3 CH3 A (a) CH3OCHOOCHOCHOCH3 C2H5 A CH3 A CH3 A (b) CH3OCH2OCHOCH2OCH3 A CH2OCH2OCH3 (c) CH2PCHOCHOCHPCH2 CH3 A (d) CH3OC COCH2OCH3 (e) OOO CH3OCH2OCHOCHPCH2 A (f)

Write structural formulas for the following organic compounds: (a) 3-methylhexane, (b) 1,3,5- trichlorocyclohexane, (c) 2,3-dimethylpentane, (d) 2-bromo- 4-phenylpentane, (e) 3,4,5- trimethyloctane.

Write structural formulas for the following compounds: (a) trans-2-pentene, (b) 2-ethyl-1-butene, (c) 4- ethyl-trans-2-heptene, (d) 3-phenyl-butyne.

Comment on the extra stability of benzene compared to ethylene. Why does ethylene undergo addition reactions while benzene usually undergoes substitution reactions?

Benzene and cyclohexane molecules both contain six-membered rings. Benzene is a planar molecule, and cyclohexane is nonplanar. Explain.

Write structures for the following compounds: (a) 1-bromo-3-methylbenzene, (b) 1-chloro-2- propylbenzene, (c) 1,2,4,5-tetramethylbenzene

Name the following compounds: (a) Cl A A CH3 HCl NO2 A A NO2 HCH2CH3 (b) CH3 A A CH3 (c) H3C E ECH3

What are functional groups? Why is it logical and useful to classify organic compounds according to their functional groups?

Draw the Lewis structure for each of the following functional groups: alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine.

Draw structures for molecules with the following formulas: (a) CH4O, (b) C2H6O, (c) C3H6O2, (d) C3H8O.

Classify each of the following molecules as alcohol, aldehyde, ketone, carboxylic acid, amine, or ether: (a) CH3OCH2CH3 (b) CH3CH2NH2 (c) CH3OCH2OC J O G H (d) CH3OCOCH2OCH3 B O (e) HOCOOH O B (f) CH3CH2CH2OH OCH2OCOOCOOH NH2 A A H O B (g)

Generally aldehydes are more susceptible to oxidation in air than are ketones. Use acetaldehyde and acetone as examples and show why ketones such as acetone are more stable than aldehydes in this respect.

Complete the following equation and identify the products: HCOOH 1 CH3OH

A compound has the empirical formula C5H12O. Upon controlled oxidation, it is converted into a compound of empirical formula C5H10O, which behaves as a ketone. Draw possible structures for the original compound and the final compound

A compound having the molecular formula C4H10O does not react with sodium metal. In the presence of light, the compound reacts with Cl2 to form three compounds having the formula C4H9OCl. Draw a structure for the original compound that is consistent with this information

Predict the product or products of each of the following reactions: (a) CH3CH2OH 1 HCOOH (b) HOC C OOO OCH3 H2 88n CPC HBr 888n C2H5 G H D D H G H (c)

Identify the functional groups in each of the following molecules: (a) CH3CH2COCH2CH2CH3 (b) CH3COOC2H5 (c) CH3CH2OCH2CH2CH2CH3

Draw all the possible structural isomers for the molecule having the formula C7H7Cl. The molecule contains one benzene ring.

Given these data C2H4(g) 1 3O2(g) 2CO2(g) 1 2H2O(l) H 5 21411 kJ/mol 2C2H2(g) 1 5O2(g) 4CO2(g) 1 2H2O(l) H 5 22599 kJ/mol H2(g) 1 1 2O2(g) H2O(l) H 5 2285.8 kJ/mol calculate the heat of hydrogenation for acetylene: C2H2(g) 1 H2(g) C2H4(g)

State which member of each of the following pairs of compounds is the more reactive and explain why: (a) propane and cyclopropane, (b) ethylene and methane, (c) acetaldehyde and acetone.

State which of the following types of compounds can form hydrogen bonds with water molecules: (a) carboxylic acids, (b) alkenes, (c) ethers, (d) aldehydes, (e) alkanes, (f) amines.

An organic compound is found to contain 37.5 percent carbon, 3.2 percent hydrogen, and 59.3 percent fluorine by mass. The following pressure and volume data were obtained for 1.00 g of this substance at 90C: P (atm) V (L) 2.00 0.332 1.50 0.409 1.00 0.564 0.50 1.028 The molecule is known to have no dipole moment. (a) What is the empirical formula of this substance? (b) Does this substance behave as an ideal gas? (c) What is its molecular formula? (d) Draw the Lewis structure of this molecule and describe its geometry. (e) What is the systematic name of this compound?

State at least one commercial use for each of the following compounds: (a) 2-propanol (isopropanol), (b) acetic acid, (c) naphthalene, (d) methanol, (e) ethanol, (f) ethylene glycol, (g) methane, (h) ethylene.

How many liters of air (78 percent N2, 22 percent O2 by volume) at 20C and 1.00 atm are needed for the complete combustion of 1.0 L of octane, C8H18, a typical gasoline component that has a density of 0.70 g/mL?

How many carbon-carbon sigma bonds are present in each of the following molecules? (a) 2- butyne, (b) anthracene (see Figure 24.7), (c) 2,3-dimethylpentane

How many carbon-carbon sigma bonds are present in each of the following molecules? (a) benzene, (b) cyclobutane, (c) 3-ethyl-2-methylpentane

The combustion of 20.63 mg of compound Y, which contains only C, H, and O, with excess oxygen gave 57.94 mg of CO2 and 11.85 mg of H2O. (a) Calculate how many milligrams of C, H, and O were present in the original sample of Y. (b) Derive the empirical formula of Y. (c) Suggest a plausible structure for Y if the empirical formula is the same as the molecular formula.

Draw all the structural isomers of compounds with the formula C4H8Cl2. Indicate which isomers are chiral and give them systematic names.

The combustion of 3.795 mg of liquid B, which contains only C, H, and O, with excess oxygen gave 9.708 mg of CO2 and 3.969 mg of H2O. In a molar mass determination, 0.205 g of B vaporized at 1.00 atm and 200.0C and occupied a volume of 89.8 mL. Derive the empirical formula, molar mass, and molecular formula of B and draw three plausible structures.

Beginning with 3-methyl-1-butyne, show how you would prepare the following compounds: CH2PCOCHOCH3 CH3 A Br A (a) CH2BrOCBr2OCHOCH3 CH3 A (b) CH3OCHOCHOCH3 CH3 A Br A (c)

Indicate the asymmetric carbon atoms in the following compounds: CH3OCH2OCHOCHOCONH2 CH3 A A NH2 O B (a) H A A H H A A Br H A A (b) Br

Suppose benzene contained three distinct single bonds and three distinct double bonds. How many different isomers would there be for dichlorobenzene (C6H4Cl2)? Draw all your proposed structures.

Write the structural formula of an aldehyde that is a structural isomer of acetone.

Draw structures for the following compounds: (a) cyclopentane, (b) cis-2-butene, (c) 2-hexanol, (d) 1,4-dibromobenzene, (e) 2-butyne.

Name the classes to which the following compounds belong: (a) C4H9OH (b) CH3OC2H5 (c) C2H5CHO (d) C6H5COOH (e) CH3NH2

Ethanol, C2H5OH, and dimethyl ether, CH3OCH3, are structural isomers. Compare their melting points, boiling points, and solubilities in water.

Amines are Brnsted bases. The unpleasant smell of fish is due to the presence of certain amines. Explain why cooks often add lemon juice to suppress the odor of fish (in addition to enhancing the flavor).

You are given two bottles, each containing a colorless liquid. You are told that one liquid is cyclohexane and the other is benzene. Suggest one chemical test that would allow you to distinguish between these two liquids

Give the chemical names of the following organic compounds and write their formulas: marsh gas, grain alcohol, wood alcohol, rubbing alcohol, antifreeze, mothballs, chief ingredient of vinegar.

The compound CH3CCCH3 is hydrogenated to an alkene using platinum as the catalyst. Predict whether the product is the pure trans isomer, the pure cis isomer, or a mixture of cis and trans isomers. Based on your prediction, comment on the mechanism of the heterogeneous catalysis.

How many asymmetric carbon atoms are present in each of the following compounds? H A A Cl H A A H H A A H (a) HOCOCOCOCl OH A A H CH3 A A H (b) H3COCOOCOCH2OH CH2OH A C A H OH A C A H OH A C A H H A C A OH H A C A HO (c) O

Isopropanol is prepared by reacting propylene (CH3CHCH2) with sulfuric acid, followed by treatment with water. (a) Show the sequence of steps leading to the product. What is the role of sulfuric acid? (b) Draw the structure of an alcohol that is an \ isomer of isopropanol. (c) Is isopropanol a chiral molecule? (d) What property of isopropanol makes it useful as a rubbing alcohol?

When a mixture of methane and bromine vapor is exposed to light, the following reaction occurs slowly: CH4(g) 1 Br2(g) CH3Br(g) 1 HBr(g) Suggest a mechanism for this reaction. (Hint: Bromine vapor is deep red; methane is colorless.)

Under conditions of acid catalysis, alkenes react with water to form alcohols. As in the case with hydrogen halides, the addition reaction in the formation of alcohols is also governed by Markovnikovs rule. An alkene of approximate molar mass of 42 g reacts with water and sulfuric acid to produce a compound that reacts with acidic potassium dichromate solution to produce a ketone. Identify all the compounds in the preceding steps.

2-Butanone can be reduced to 2-butanol by reagents such as lithium aluminum hydride (LiAlH4). (a) Write the formula of the product. Is it chiral? (b) In reality, the product does not exhibit optical activity. Explain.

Write the structures of three alkenes that yield 2-methylbutane on hydrogenation.

An alcohol was converted to a carboxylic acid with acidic potassium dichromate. A 4.46-g sample of the acid was added to 50.0 mL of 2.27 M NaOH and the excess NaOH required 28.7 mL of 1.86 M HCl for neutralization. What is the molecular formula of the alcohol?

Write the structural formulas of the alcohols with the formula C6H13O and indicate those that are chiral. Show only the C atoms and the OH groups

Fat and oil are names for the same class of compounds, called triglycerides, which contain three ester groups CH2OOOCOR A A A CHOOOCOR? A A A CH2OOOCOR? O B O B O B A fat or oil where R, R9, and R represent long hydrocarbon chains. (a) Suggest a reaction that leads to the formation of a triglyceride molecule, starting with glycerol and carboxylic acids (see p. 474 for structure of glycerol). (b) In the old days, soaps were made by hydrolyzing animal fat with lye (a sodium hydroxide solution). Write an equation for this reaction. (c) The difference between fats and oils is that at room temperature, the former are solids and the latter are liquids. Fats are usually produced by animals, whereas oils are commonly found in plants. The melting points of these substances are determined by the number of CC bonds (or the extent of unsaturation) presentthe larger the number of CC bonds, the lower the melting point and the more likely that the substance is a liquid. Explain. (d) One way to convert liquid oil to solid fat is to hydrogenate the oil, a process by which some or all of the CC bonds are converted to CC bonds. This procedure prolongs shelf life of the oil by removing the more reactive CC group and facilitates packaging. How would you carry out such a process (that is, what reagents and catalyst would you employ)? (e) The degree of unsaturation of oil can be determined by reacting the oil with iodine, which reacts with the CC bond as follows: I I A A A A A A A A OCOCPCOCO + I2 88n OCOCOCOCO A A A A A A The procedure is to add a known amount of iodine to the oil and allow the reaction to go to completion. The amount of excess (unreacted) iodine is determined by titrating the remaining iodine with a standard sodium thiosulfate (Na2S2O3) solution: I2 1 2Na2S2O3 Na2S4O6 1 2NaI The number of grams of iodine that react with 100 grams of oil is called the iodine number. In one case, 43.8 g of I2 were treated with 35.3 g of corn oil. The excess iodine required 20.6 mL of a 0.142 M Na2S2O3 for neutralization. Calculate the iodine number of the corn oil.

Problem 1E When a transition metal atom forms an ion, which electrons are lost first?

Problem 1SAQ What is the electron configuration of the Cu+ ion? a) [Ar]4s23d9 b) [Ar]4s23d8 c) [Ar]4s13d9 d) [Ar]4s03d10

Problem 2E Explain why transition metals exhibit multiple oxidation states instead of a single oxidation state (like most of the main-group metals).

Problem 2SAQ Which metal has the highest first ionization energy? a) Ti b) Mn c) Ru d) Au

Problem 3E Why is the +2 oxidation state so common for transition metals?

Problem 3SAQ What is the name of the compound [CoCI(NH3)5]CI2? a) pentaamminetrichlorocobalt(lll) chloride b) pentaamminechlorocobalt(lll) chloride c) pentaamminechlorocobalt(ll) chloride d) pentaamminetrichlorocobalt(ll) chloride

Problem 4E Explain why atomic radii of elements in the third row of the transition metals are no larger than those of elements in the second row.

Problem 4SAQ

Problem 5E Gold is the most electronegative transition metal. Explain.

Problem 6E Briefly define each term. a. coordination number b. ligand c. bidentate and polydentate d. complex ion e. chelating agent

Problem 5SAQ Which complex ion can exhibit geometric isomerism? Assume that M is the metal ion, A and B are ligands, and the geometry is octahedral. a) [MA6]2+ b) [MA5B]2+ c) [MA4B2]2+ d) [MA3B3]2+

Problem 6SAQ Pick the optical isomer of the complex ion represented here:

Problem 7E Using the Lewis acid-base definition, how would you categorize a ligand? How would you categorize a transition metal ion?

According to valence bond theory, what is the hybridization of the central metal ion in an octahedral complex ion? a) sp b) \(sp^3\) c) \(dsp^2\) d) \(d^2 sp^3\)

Problem 8E

Which complex ion geometry has the potential to exhibit cis–trans isomerism: linear, tetrahedral, square planar, octahedral?

Problem 8SAQ Estimate the crystal field splitting energy (in kJ/mol) for a complex ion that is red in solution. a) 228 kJ/mol b) 171 kJ/mol c) 2.84 × 10-19 kJ/mol d) 3.79 × 10-19 kJ/mol

Problem 9SAQ Use crystal fi eld theory to determine the number of unpaired electrons in the complex ion [Fe(CN)6]4- . a) 0 b) 2 c) 3 d) 4

Problem 10E How can you tell whether a complex ion is optically active?

Problem 10SAQ Which complex ion is diamagnetic? a) [Cr(H2O)4Cl2 ] + b) [Fe(H2O)6 ] 2+ c) [Co(NH3) 6 ] 3+ d) [CoCl6 ]3-

Problem 11E Explain the differences between weak-field and strong-fieldmetal complexes.

Problem 12E Explain why compounds of Sc3+ are colorless, but compounds of Ti3+ are colored.

Explain why compounds of \(\mathrm{Zn}^{2+}\) are white, but compounds of \(\mathrm{Cu}^{2+}\) are often blue or green.

Problem 14E Explain the differences between high-spin and low-spin metal complexes.

Problem 15E Why are almost all tetrahedral complexes high-spin?

Problem 16E Many transition metal compounds are colored. How does crystal field theory account for this?

Write the ground state electron configuration for each atom and ion pair. a. \(\mathrm{Ni}, \ \mathrm{Ni}^{2+}\) b. \(\mathrm{Mn}, \ \mathrm{Mn}^{4+}\) c. \(\mathrm{Y}, \ \mathrm{Y}^{+}\) d. \(\mathrm{Ta}, \ \mathrm{Ta}^{2+}\)

Problem 18E Write the ground state electron configuration for each atom and ion pair. a. Zr, Zr2+ b. Co, Co2+ c. Tc, Tc3+ d. Os, Os4+

Determine the highest possible oxidation state for each element. a. V b. Re c. Pd

Problem 20E Which first-row transition metal(s) has the following highest possible oxidation state? a. +3 b. +7 c. +4

Problem 21E Determine the oxidation state and coordination number of the metal ion in each complex ion. a. [Cr(H2O)6]3+ b. [Co(NH3)3Cl3]- c. [Cu(CN)4]2- d. [Ag(NH3)2]+

Problem 22E Determine the oxidation state and coordination number of the metal ion in each complex ion. a. [Co(NH3)5Br]2+ b. [Fe(CN)6]4- c. [Co(ox)3]4- d. [PdCl4]2-

Problem 23E

Problem 24E

Problem 25E

Problem 26E

Write the formula and the name of each complex ion. a. a complex ion with \(\mathrm{Co}^{3+}\) as the central ion and three \(\mathrm{NH}_{3}\) molecules and three \(\mathrm{CN}^{-}\) ions as ligands b. a complex ion with \(\mathrm{Cr}^{3+}\) as the central ion and a coordination number of 6 with ethylenediamine ligands

Problem 28E

Problem 29E

Problem 30E

Problem 31E

Which complexes exhibit geometric isomerism? a. \(\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{5}(\mathrm{OH})\right]^{2+}\) b. \(\left[\mathrm{Cr}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right]^{+}\) c. \(\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}_{2}\right]^{+}\) d. \(\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right) \mathrm{Cl}_{3}\right]^{-}\) e. \(\left[\mathrm{Pt}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}(\mathrm{CN})_{2}\right]\)

Problem 32E

Problem 34E Which complexes exhibit geometric isomerism? a. [Co(H2O)2(ox)2]- b. [Co(en)3]3+ c. [Co(H2O)2(NH3)2(ox)]+ d. [Ni(NH3)2(en)]2+ e. [Ni(CO)2Cl2]

If \(\mathrm{W}, \mathrm{X}, \mathrm{Y}\), and \(\mathrm{Z}\) are different monodentate ligands, how many geometric isomers are there for each ion? (a) square planar \([\mathrm{NiWXYZ}]^{2+}\) (b) tetrahedral \([\mathrm{ZnWXYZ}]^{2+}\)

Problem 36E

Problem 37E

Problem 38E

Problem 39E

Problem 40E

Problem 41E

Problem 43E

Problem 42E

Problem 47E

Problem 52

Problem 55E Hemoglobin exists in two predominant forms in our bodies. One form, known as oxyhemoglobin, has O2 bound to the iron and the other, known as deoxyhemoglobin, has a water molecule bound instead. Oxyhemoglobin is a low-spin complex that gives arterial blood its red color, and deoxyhemoglobin is a high-spin complex that gives venous blood its darker color. Explain these observations in terms of crystal field splitting. Would you categorize O2 as a strong- or weak-field ligand?

Problem 63E Oxalic acid solutions remove rust stains. Draw a complex ion that is likely responsible for this effect. Does it have any isomers?

Problem 67E Draw the structures of all the geometric isomers of [Ru(H20)2(NH3)2CI2]+ . Draw the mirror images of any that are chiral.

When a solution of \(\mathrm{PtCl}_{2}\) reacts with the ligand trimethylphosphine, \(\mathrm{P}\left(\mathrm{CH}_{3}\right)_{3}\), two compounds are produced. The compounds share the same elemental analysis: 46.7% Pt; 17.0% Cl; 14.8% P; 17.2% C; 4.34% H. Determine the formula, draw the structure, and give the systematic name for each compound.

Problem 68E A 0.32 mol amount of NH3 is dissolved in 0.47 L of a 0.38 M silver nitrate solution. Calculate the equilibrium concentrations of all species in the solution.

Problem 70E Draw a crystal field splitting diagram for a trigonal planar complex ion. Assume the plane of the molecule is perpendicular to the z axis.

Problem 71E Draw a crystal field splitting diagram for a trigonal bipyramidal complex ion. Assume the axial positions are on the z axis.

Problem 72E

Problem 73E

Problem 74E

Problem 75E Halide complexes of metal M of the form [MX6]3- are found to be stable in aqueous solution. But it is possible that they undergo rapid ligand exchange with water (or other ligands) that is not detectable because the complexes are less stable. This property is referred to as their lability. Suggest an experiment to measure the lability of these complexes that does not employ radioactive labels.

Problem 76E

Problem 77 When solid Cd(OH)2 is added to a solution of 0.10 M Nal some of it dissolves. Calculate the pH of the solution at equilibrium.

Problem 80E The complexes of Fe3+ have magnetic properties that depend on whether the ligands are strong or weak field. Explain why this observation supports the idea that electrons are lost from the 4 s orbital before the 3 d orbitals in the transition metals.

Problem 79E Which element has the higher ionization energy, Cu or Au?