Ch.23 - Organic and Biological Chemistry
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Problem 2.142
Butane, the fuel used in disposable lighters, has the formula C4H10. The carbon atoms are connected in the sequence C-C-C-C, and each carbon has four covalent bonds. Draw the structural formula of butane.
- What is the difference between a straight-chain alkane and a branched-chain alkane?
Problem 4
- How many dienes (compounds with two double bonds) are there with the formula C5H8? Draw as many structures as you can.
Problem 6
- What is the structural difference between an aldose and a ketose?
Problem 7
- Spermaceti, a fragrant substance isolated from sperm whales, was a common ingredient in cosmetics until its use was banned in 1976 to protect the whales from extinction. Chemically, spermaceti is cetyl palmitate, the ester of palmitic acid with cetyl alcohol (the straight-chain C16 alcohol). Show the structure of spermaceti.
Problem 9
- If the sequence T-A-C-C-G-A appeared on one strand of DNA, what sequence would appear opposite it on the other strand?
Problem 13
Problem 23.30
Convert the following model into a condensed structure and line drawing. Draw the structures of two isomeric compounds.
Problem 23.31
Convert the following models into a condensed structures and line drawings.
(a)
Problem 23.56a
Propose structures and draw condensed formulas for molecules that meet the following descriptions.
(a) A ketone with the formula C5H10
Problem 23.56b
Propose structures and draw condensed formulas for molecules that meet the following descriptions.
(b) An ester with the formula C6H12O2
Problem 23.56c
Propose structures and draw condensed formulas for molecules that meet the following descriptions.
(c) A compound with formula C2H5NO2 that is both an amine and a carboxylic acid
Problem 23.57a
Give line drawings for each of the following molecular formulas. You may have to use rings and/or multiple bonds in some instances.
(a) C2H7N
- What is the difference in the chemical formula between a straight-chain alkane and a cycloalkane, each with the same number of carbon atoms?
Problem 41
- Draw a straight-chain alkane with 6 carbon atoms as a condensed structure and as a line drawing.
Problem 42
- Methionine, one of the 20 amino acid building blocks from which proteins are made, has the following structure. What is the chemical formula of methionine? In writing the for-mula, list the element symbols in alphabetical order, and give the number of each element as a subscript.
Problem 43
- Which of these objects are chiral (exhibit handedness)? (a) Basketball (b) Foot (c) Golf club (d) Coffee mug (e) Seashell with a helical twist
Problem 48
- What are functional groups, and why are they important?
Problem 54
- Describe the structure of the functional group in each of the following families: (a) Alkene, (b) Alcohol, (c) Ester, (d) Amine.
Problem 55
- Give line drawings for each of the following molecular formulas. You may have to use rings and/or multiple bonds in some instances. (b) C4H8 (c) C2H4O (d) CH2O2
Problem 57
- Provide a line drawing and the molecular formula for the following: (a) A linear alkyne with three carbon atoms and one triple bond, (b) A linear alkene with four carbon atoms and one double bond, (c) A cyclic alkene with five carbon atoms in a ring and two double bonds.
Problem 58
- Give a line drawing and molecular formula for the following: (a) A linear alkane with four carbon atoms, (b) An alkene with six carbon atoms in a ring and one double bond, (c) A linear alkyne with six carbon atoms and two triple bonds.
Problem 59
- Propose structures and draw condensed formulas of the three isomers with the formula C3H8O.
Problem 61
- If someone reported the preparation of a compound with the formula C3H9, most chemists would be skeptical. Why?
Problem 62
- Benzyne, C6H4, is a highly energetic and reactive molecule. The carbon atoms are connected in a six-membered ring. Provide a line drawing for benzyne. What functional group is present?
Problem 69
- Write the open-chain structure of a ketotetrose.
Problem 72
- Write the open-chain structure of a four-carbon deoxy sugar.
Problem 73
- (a) Draw an orbital overlap picture of ethane (CH3CH3), assuming both carbon atoms are sp3 hybridized. What are the C–H bond angles in this drawing? (b) Draw an orbital overlap picture of ethane, assuming both carbon atoms are sp2 hybridized. What are the C–H bond angles in this drawing? (c) The real structure of ethane is like the picture you drew in part (a). Use VSEPR theory to explain why your picture from part (a) makes a more stable molecule than your picture in part (b).
Problem 76
- Draw an orbital overlap picture of methane (CH₄) with the carbon in sp3 hybridization and an orbital overlap picture of a molecule with carbon in sp2 hybridization. Explain why the carbon atom in methane is more stable in sp3 hybridization than in sp2 hybridization.
Problem 77
- Unlike palmerolide A (Problem 23.80), which has a large ring, a cyclic molecule with only six atoms can only have a cis double bond, but not a trans double bond. Give a line drawing of a cyclic molecule with six carbon atoms and a cis double bond. Explain why it cannot have a trans double bond.
Problem 81
- Which of the following compounds are capable of cis–trans isomerism? (a) 1-Hexene (b) 2-Hexene (c) 3-Hexene
Problem 84