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- Give the geometry and approximate bond angles around the central atom in CCl3-. (LO 8.1) (a) Trigonal planar, 120° (b) Trigonal pyramidal, 109.5° (c) Trigonal pyramidal, 120° (d) Bent, 109.5°
Problem 2
- The following diagrams illustrate p-p orbital overlap or s-p orbital overlap. Which diagram represents a p bond in valence bond theory? (LO 8.3) (a)
Problem 5
(b)
(c)
(d)
- Which of the following molecules has a central atom with sp3 hybridization? (LO 8.4) (a) PCl5 (b) OF2 (c) CO2 (d) SF4
Problem 6
- The connections between atoms in the amino acid histidine are shown. Complete the electron-dot structure by adding multiple bonds and lone pairs of electrons. Give the hybridization on the numbered carbon and nitrogen atoms. (LO 8.4)
Problem 7
(a) N1 = sp2, N2 = sp, C1 = sp2, C2 = sp3 (b) N1 = sp2, N2 = sp2, C1 = sp3, C2 = sp2 (c) N1 = sp3, N2 = sp, C1 = sp2, C2 = sp3 (d) N1 = sp3, N2 = sp2, C1 = sp2, C2 = sp3
- Use the chemical structure for Tagamet, a drug used to treat peptic ulcers and heartburn, to answer questions 8 and 9.
Problem 8
Which orbitals overlap to form bond 1? (LO 8.5) (a) s bond: N 1sp22 with C 1sp22; p bond: N (p) with C (p) (b) N 1sp22 with C 1sp22 (c) s bond: N 1sp22 with C 1sp22; p bond: N 1sp22 with C 1sp22 (d) s bond: N (sp) with C 1sp22; p bond: N (p) with C (p)
- Use the chemical structure for Tagamet, a drug used to treat peptic ulcers and heartburn, to answer questions 8 and 9.
Problem 9
Which orbitals overlap to form bond 2? (LO 8.5) (a) C (sp) with C (sp) (b) C (sp) with C 1sp22 (c) C 1sp22 with C 1sp22 (d) C 1sp32 with C 1sp22
- The C2 molecule has a MO diagram similar to N2 (Figure 8.22a). What is the bond order of C2 and is it paramagnetic or diamagnetic? (LO 8.12) (a) Bond order = 2, diamagnetic (b) Bond order = 2, paramagnetic (c) Bond order = 0, paramagnetic (d) Bond order = 3>2, diamagnetic
Problem 15
- What is the geometry around the central atom in each of the following molecular models? (a)
Problem 27
Problem 29
Three of the following molecular models have a tetrahedral central atom, and one does not. Which is the odd one? (There may be a 'hidden' atom directly behind a visible atom in some cases.) (a)
(b)
(c)
(d)
- The VSEPR model is a simple predictive tool that is usually, but not always, correct. Take urea, for instance, a waste product excreted in animal urine:
Problem 31
What hybridization would you expect for the C and N atoms in urea according to the VSEPR model, and what approximate values would you expect for the various bond angles? What are the actual hybridizations and bond angles based on the molecular model shown? 1Red = O, gray = C, blue = N, ivory = H.2
- The following ball-and-stick molecular model is a representation of acetaminophen, the active ingredient in such over-thecounter headache remedies as Tylenol. 1Red = O, gray = C, blue = N, ivory = H.2 (c) What is the geometry around each carbon?
Problem 32
Problem 32a
The following ball-and-stick molecular model is a representation of acetaminophen, the active ingredient in such over-thecounter headache remedies as Tylenol. (Red = O, gray = C, blue = N, ivory = H.) (a) What is the formula of acetaminophen?
Problem 32b
The following ball-and-stick molecular model is a representation of acetaminophen, the active ingredient in such over-thecounter headache remedies as Tylenol. (Red = O, gray = C, blue = N, ivory = H.) (b) Indicate the positions of the multiple bonds in acetaminophen.
Problem 33a
The following ball-and-stick molecular model is a representation of thalidomide, a drug that causes birth defects when taken by expectant mothers but is valuable for its use against leprosy. The lines indicate only the connections between atoms, not whether the bonds are single, double, or triple. 1Red = O, gray = C, blue = N, ivory = H.2 (a) What is the formula of thalidomide?
Problem 34
Ethyl acetate, CH3CO2CH2CH3, is commonly used as a solvent and nail-polish remover. Look at the following electrostatic potential map of ethyl acetate, and explain the observed polarity.
Problem 37b
Two dichloroethylene molecules with the same chemical formula 1C2H2Cl22, but different arrangements of atoms are shown. (b) Which form of dichloroethylene has a dipole moment of 2.39 D, and which has a dipole moment of 0.00 D?
- What geometric arrangement of charge clouds do you expect for atoms that have the following number of charge clouds? (a) 3 (b) 5 (c) 2 (d) 6
Problem 38
- What shape do you expect for molecules that meet the following descriptions? (a) A central atom with two lone pairs and three bonds to other atoms (b) A central atom with two lone pairs and two bonds to other atoms (c) A central atom with two lone pairs and four bonds to other atoms
Problem 39
- How many charge clouds are there around the central atom in molecules that have the following geometry? (a) Tetrahedral (b) Octahedral (c) Bent (d) Linear (e) Square pyramidal (f) Trigonal pyramidal
Problem 40
- What bond angles do you expect for each of the following? (d) The O¬B¬O angle in BO33-
Problem 49
- Oceanographers study the mixing of water masses by releasing tracer molecules at a site and then detecting their presence at other places. The molecule trifluoromethylsulfur pentafluoride is one such tracer. Draw an electron-dot structure for CF3SF5, and predict the bond angles around both carbon and sulfur.
Problem 52
- A potential replacement for the chlorofluorocarbon refrigerants that harm the Earth's protective ozone layer is a compound called E143a, or trifluoromethyl methyl ether, F3COCH3. Draw an electron-dot structure for F3COCH3, and predict the geometry around both the carbons and the oxygen.
Problem 53
- Like cyclohexane (Problem 8.54), benzene also contains a sixmembered ring of carbon atoms, but it is flat rather than puckered. Explain, and predict the values of the C¬C¬C bond angles.
Problem 55
- Use VSEPR theory to answer the following questions: (a) Which molecule, BF3 or PF3, has the smaller F¬X¬F angles?
Problem 56
- Draw an electron-dot structure for each of the following substances, and predict the molecular geometry of every nonterminal atom. (a) F3S¬S¬F
Problem 57
- What is the difference in spatial distribution between electrons in a p bond and electrons in a s bond?
Problem 58
- What hybridization do you expect for atoms that have the following numbers of charge clouds? (c) 4
Problem 60
- What spatial arrangement of charge clouds corresponds to each of the following kinds of hybridization? (a) sp3
Problem 61
- Oxaloacetic acid is an intermediate involved in the citric acid cycle of food metabolism. What is the hybridization of the various carbon atoms in oxaloacetic acid, and what are the approximate values of the various bond angles?
Problem 64
- Describe the hybridization of the carbon atom in the poisonous gas phosgene, Cl2CO, and make a rough sketch of the molecule showing its hybrid orbitals and p bonds.
Problem 66