Ch.4 Molecular Compounds
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Problem 2
Based on bond energies, which atmospheric gas in each pair do you think is more stable? Explain. a. O2 or N2 b. CO or CO2Problem 2
How many covalent bonds are formed by each atom in the following molecules? Draw molecules using the electron-dot-symbols and lines to show the covalent bonds. a. PH₃ b. H₂Se c. HCl d. SiF₄
Problem 3
What are likely formulas for the following molecules? (a) CH₂Clɂ (b) BHɂ (c) NIɂ (d) SiClɂProblem 32
What is a coordinate covalent bond, and how does it differ from a covalent bond?Problem 34
Identify the bonds formed between the following pairs of atoms as either covalent or ionic. d. Zinc and fluorineProblem 35
Write electron-dot symbols to show the number of covalent bonds and the lone pairs of electrons in the molecules that are formed by reactions between the atoms in Problem 4.34.Problem 38
Which of the following contains a coordinate covalent bond? (Hint: How many covalent bonds would you expect the central atom (underlined/bold) to form?) a. PbCl₂ b. Cu (NH₃)₄²⁺ c. NH⁺₄Problem 41
A compound of gallium with chlorine has a melting point of 77°C and a boiling point of 201°C. Is the compound ionic or covalent? What is a likely formula?Problem 44
Distinguish between the following: c. A lone pair and a shared pair of elecctronsProblem 49
Consider the following possible structural formulas for C₃H₆O₂ . If a structure is not reasonable, explain what changes could be made to convert it to a reasonable structure. a.
Problem 53
Expand the following condensed structures into the correct structural formulas. c. CH₃CH₂OCH₂ClProblem 62
Draw a Lewis structure for the following polyatomic ions: b. Sulfite, SO²⁻₃Problem 65
Sketch the three-dimensional shape of the following molecules: a. Methylamine, CH₃NH₂Problem 75
Based on electronegativity differences, would you expect bonds between the following pairs of atoms to be largely ionic or largely covalent? b. Ca and ClProblem 85
The discovery in the 1960s that xenon and fluorine react to form a molecular compound was a surprise to most chemists, because it had been thought that noble gases could not form bonds. a. Why was it thought that noble gases could not form bonds?Problem 88
The following formulas are unlikely to be correct. What is wrong with each? d. C₂OSProblem 89
Which of the following compounds contain ionic bonds? Which contain covalent bonds? Which contain coordinate covalent bonds? (A compound may contain more than one type of bond.) a. BaCl₂Problem 90
The phosphonium ion, PH⁺₄ is formed by reaction of phosphine, PH₃ , with an acid. b. Predict its molecular geometry.Problem 90
The phosphonium ion, PH⁺₄ is formed by reaction of phosphine, PH₃ , with an acid. d. Explain why the ion has a +1 charge.Problem 93
The sulfite ion (SO₃²⁻) and sulfur trioxide (SO₃) have the same chemical formulas but different molecular geometries. Draw the Lewis dot structures and identify the molecular geometry of each.Problem 100
Which of the following elements would you expect to form (iv) both covalent and ionic bonds? (More than one answer may apply; remember that some nonmetals can form ionic bonds with metals.) Explain your answers. a.Oxygen b.Potassium c.Phosphorus d.Iodine e.Hydrogen f.Cesium
