Organic Chemistry Questions ch.9
1. Heptane has 7 carbon atoms. What is the chemical formula of heptane?
2. Nonane has 9 carbon atoms. What is its chemical formula?
3. An alkane has 4 carbon atoms. How many hydrogen atoms does it have?
4. Candle wax contains an alkane with 52 hydrogen atoms. How many carbon atoms does this alkane have?
5. Name each compound.
6. Identify any errors in the name of each hydrocarbon.
(a) 2,2,3-dimethylbutane
(b) 2,4-diethyloctane
(c) 3-methyl-4,5-diethyl-nonane
8. Draw a condensed structural diagram for each hydrocarbon.
(a) propane
(b) 4-ethyl-3-methylheptane
(c) 3-methyloctane
9. Use each incorrect name to draw the corresponding hydrocarbon. Examine your drawing, and rename the
hydrocarbon correctly.
(a) 3-propyl-butane
(b) 1,3-dimethyl-hexane
(c) 4-methylpentane
10. Draw a line structural diagram for each alkane.
(a) 3-ethyl-3,4-dimethyloctane
(b) 2,3,4-trimethylhexane
(c) 5-ethyl-3,3-dimethylheptane
(d) 6-isobutyl-4-ethyl-5-methyldecane
11. One way to assess how well you have learned a new skill is to identify mistakes. Examine the following
compounds and their names. Identify any mistakes, and correct the names.
(a) 4-ethyl-2-methylpentane
(b) 4,5-methylhexane
(c) 3-methyl-3-ethylpentane
12. The following equation shows the combustion of 3-ethyl-2,5-dimethylheptane:
C11H24 + 17O2 → 11CO2 + 12H2O
(a) Does this equation show complete or incomplete combustion?
(b) Draw the structural formula for 3-ethyl-2,5-dimethylheptane.
13. (a) Write a balanced equation for the complete combustion of pentane,C5H12.
(b) Write a balanced equation for the complete combustion of octane,C8H18.
(c) Write two possible balanced equations for the incomplete combustion of ethane, C2H6
14. The flame of a butane lighter is usually yellow, indicating incomplete combustion of the gas. Write a
balanced chemical equation to represent the incomplete combustion of butane in a butane lighter. Use the
condensed structural formula for butane.
15. The paraffin wax in a candle burns with a yellow flame. If it had sufficient oxygen to burn with a blue
flame, it would burn rapidly and release a lot of energy. It might even be dangerous! Write the balanced
chemical equation for the complete combustion of candle wax, C25H52(s).
16. 4-propyldecane burns to give solid carbon, water vapour, carbon monoxide, and carbon dioxide.
(a) Draw the structural formula for 4-propyldecane.
(b) Write two different balanced equations for the reaction described in this problem.
(c) Name the type of combustion. Explain.
17. Name each hydrocarbon.
18. Draw a condensed structural diagram for each compound.
(a) 2-methyl-1-butene
(b) 5-ethyl-3,4,6-trimethyl-2-octene
19. You have seen that alkenes, such as C11H22, can have isomers. Draw condensed structural formulas for the
isomers of C4H8. Then name the isomers.
20. Draw and name the cis-trans isomers for C5H10.
21. Why can 1-butene not have cis-trans isomers? Use a structural diagram to explain.
22. Like other isomers, two cis-trans isomers have the same atomic weight. They also yield the same elements
when decomposed. How might you distinguish between two such isomers in the lab?
23. C6H12 has four possible pairs of cis-trans isomers. Draw and name all four pairs.
24. Draw the reactants and products of the following reaction.
3-ethyl-2-heptene + HOH →
Use Markovnikov’s rule to predict which of the two products will form in the greater amount.
25. Use Markovnikov’s rule to predict which of the two products will form in the greater amount.
26. Draw the major product of each reaction.
(a) CH3CH=CH2 + Br2 →
(c) CH2=CHCH2CH3 + HBr →
(b) CH2=CH2 + HOH →
(d) (CH3) 2C=CHCH2CH2CH3 + HCl →
27. For each reaction, name and draw the reactants that are needed to produce the given product.
(a) ? + ? → CH3CH(Cl)CH3
(b) ? + ? → Br-CH2CH2-Br
(c) ? + HOH → CH3CH2C(OH)(CH3)CH2 CH3
(d) CH2=CHCH3 + ? → CH3CH2CH3
28. Name each alkyne.
29. Draw a condensed structural diagram for each compound.
(a) 2-pentyne (c) 3-ethyl-4-methyl-1-hexyne
(b) 4,5-dimethyl-2-heptyne (d) 2,5,7-trimethyl-3-octyne
31. Draw a condensed structural diagram for each compound.
(a) 1,2,4-trimethylcycloheptane
(e) 1,3-ethyl-2-methylcyclopentane
(b) 2-ethyl-3-propyl-1-cyclobutene
(f) 4-butyl-3-methyl-1-cyclohexene
(c) 3-methyl-2-cyclopentene
(g) 1,1-dimethylcyclopentane
(d) cyclopentene
(h) 1,2,3,4,5,6-hexamethyl cyclohexane
32. Name the following aromatic compound.
33. Draw a structural diagram for each aromatic compound.
(a) 1-ethyl-3-methylbenzene
(b) 2-ethyl-1,4-dimethylbenzene
(c) para-dichlorobenzene
34. Give another name for the compound in question 33(a).
35. Draw and name three aromatic isomers with the molecular formula C10H14.