1. 9.9 – NOTES Alkane Boiling Points

2. A.10 Boiling Points of Alkane Isomers
The more branches, the lower the boiling point
Why are boiling points lower for branched chain?
More branches result in a more compact shape; this makes fewer intermolecular contacts (shorter chains) and makes the molecules more easily separated from each other

3. Viscosity
Resistance to flow
The more viscous something is, the less easily it flows
Viscosity and Temperature
Temperature can affect viscosity of a substance
When you increase the temperature of the fluid, the viscosity decreases, or flows more easily.
Heat goes up, viscosity goes down

5. A.11 Fuels and Climate
Different parts of the country have different climates, resulting in different fuel additives added
Automobile fuel used in Maine during the cold winter months differs from the fuel used in Arizona during hot summer

6. Why do different areas need different types of fuel?
Volatility affects performance
Warmer climates need fuels that don’t easily vaporize (vapor lock)
Colder climates need fuels that don’t solidify or become viscous

7. What physical property should be engineered to make the fuel appropriate for each climate?
Volatility
Viscosity
Molecular structure is used to vary properties to make the different chemical substances for the various materials made from petroleum