1. Given the molecular formula for the following akanes, list the name and write the condensed structural formulas for the "straight-chain" form of each.

a. CH4

b. C3H8

c. C6H14

d. C8H18

Name	Condensed Structural Formula
a. methane	CH4
b. propane	CH3CH2CH3
c. hexane	CH3CH2CH2CH2 CH2CH3
d. octane	CH3CH2CH2CH2 CH2CH2CH2CH3

2. If four (4) carbon atoms are present in each of the following hydrocarbons, use the general formula for each to determine the number of hydrogen atoms that will be present in each molecule.

a. alkane

b. cycloalkane

c. alkene

d. alkyne

Here we can use the general formulas and in each case n = 4, so the number of hydrogen atoms will be as follows:

General formula	Number of hydrogen atoms
a. CnH2n + 2	10 hydrogen atoms (2 x 4) + 2
b. CnH2n	8 hydrogen atoms (2 x 4)
c. CnH2n	8 hydrogen atoms (2 x 4)
d. CnH2n - 2	6 hydrogen atoms (2 x 4) - 2

Return to Previous Page