1. Properties of Alkanes Nonpolar molecules – not water-soluble
Relatively low melting and boiling points
Generally less dense than water
The longer the chain (greater molecular weight), the higher the melting point, boiling point, and density.

2. Name
Melting pt (°C)
Boiling pt (°C)
Density at 0°C (g/mL)
Methane
-182.5
-160
Gas
Ethane
-183.6
-88.7
Propane
-187.6
-42.2
Butane
-139.0
-0.4
Pentane
-129.9
36.0
0.626
Hexane
-94.5
68.8
0.659
Heptane
-90.6
98.4
0.684
Octane
-56.9
125.6
0.703
Nonane
-53.6
150.7
0.718
Decane
-29.7
174.0
0.730

3. Constitutional Isomers
Molecules that have the same molecular formula but a different arrangement of atoms
C4H10
CH3
CH3CH2CH2CH3 CH3CHCH3
butane 2-methylpropane
b.p. = -0.4°C, b.p. = -12°C
m.p. = -139°C m.p. = -145°C

4. Website to practice building isomers
Copy down your work into your notebook!
Name the isomers that are built for butane, pentane, hexane, and heptane.

5. Homework
Page 308: 11.5
Page 309: 11.6
Page 319: 33 & 34