2. Alkanes vs. Alkenes

3. What do you think these words mean?
Homologous Series
Saturated Hydrocarbons
Unsaturated Hydrocarbons
A group of compounds whose chemical formula increases by one carbon atom from one compound in the series to the next
Ex: CH4, C2H6, C3H8…
Hydrocarbons with all single bonds, any alkanes
Hydrocarbons without all single bonds, any alkenes or alkynes

4. Melting and Boiling Point
Look at the regular Chem text page 753
What pattern do you see in boiling point as alkanes get more carbons?
What pattern do you see as molecules get less saturated?
More carbons = higher boiling point
Less saturated = more double bonds = lower boiling point… mostly

5. Melting Point cont. Put these in order of increasing melting point:
Ethane Octane Butane 1-Octene
Ethane < Butane < 1-Octene < Octane

6. Solubility
Summary:
Alkanes and Alkenes are both NOT soluble in water. Plus, they are less dense than water.
Alkane Alkene
Water
with green food color

7. Alkanes burn cleaner than Alkenes
Combustion
Black Smoke
Summary:
Alkanes burn cleaner than Alkenes
Alkene
Alkane
Blue Flame

8. Alkane <-> Alkene
Alkane  Alkene is called cracking
Alkene  Alkane is called addition
C3H8 heat and Ni catalyst C3H6 + H2
C3H6 + H2  C3H8

9. Identifying Alkanes/enes
Alkane + Halogen  Haloalkane (slow), substitution
Alkene + Halogen Haloalkane (fast) this is called addition
C3H8 + Br2  C3H7Br + HBr
C2H4 + Br2  C2H4Br2

10. Bromine- Substitution and Addition Reactions
Plain Br2 reference
Alkene
Alkene
Alkane
Alkane
Plain Br2 reference
Summary:
Alkenes react quickly with Br2- addition
Alkanes react slowly + need UV light- substitution

11. Quick Review Alkanes and alkenes are ____ soluble in water
As # of C increases, melting point ____
As saturation decreases, melting point ____
Combustion of _____ is cleaner than _____
Alkanes change into alkenes with _____ and _____
Alkenes turn into alkanes with _____
An ____ reacts quickly to decolorize Br2
NOT
increases
decreases
alkanes
alkenes
heat
Nickel catalyst
hydrogen
alkene

12. We need fat in our diet To… Cholesterol too
Absorb shock, warmth, energy, move electrical/nerve currents, construct membranes, brain function, sex glands, hormone function
Cholesterol too
Can be from food, but our body makes all we need
Hormones, steroids, skin protectant, antioxidant
“Good cholesterol”= HDL, “Bad” = LDL
Click here…

13. Saturated Fats Avoid Them!
Animal products + coconut and palm oils, peanuts, butter
Solids at room temperature and body temperature
Can stack up on each other because the structures are floppy, even form crystal structures (aggregate)
Insoluble in water
What they can do that’s bad:
Deposit within cells, organs, arteries, and under skin
In arteries = atherosclerosis which hardens arteries and increases blood pressure
Make blood platelets stickier which = blood clots
clot to brain = stroke, clot to heart = heart attack
Decrease blood oxygen supply because red blood cells stick together and are less mobile
Increase bad (LDL) cholesterol and block the effects of good (HDL) cholesterol
Interfere with insulin function
Avoid Them!

14. Oils
This shows the result when different butters and oils are combined with bromine.
Which brand has the most saturated fat? Which has the least?
So… Coconut oil is the worst and Wesson “best blend” is the best
Most Unsat. Fat
Most Sat Fat

15. Unsaturated Fats Monounsaturated Polyunsaturated
Have a very slight + and – charge, so they repel each other, keeping them fluid (liquid at room and body temperature) and unable to aggregate like saturated fats
Less stable (more likely to oxidize, turn rancid) than saturated fats
From 1 to 6 double bonds
Monounsaturated
Decrease bad (LDL, which sticks to the walls of your arteries) cholesterol and increase good (HDL, which is essential to your body function + prevents inflammation of arteries)
Olive oil, canola oil, avocado, nuts, butter
Polyunsaturated
Decrease the bad (LDL), but don’t effect the good
Omega fatty acids (increase brain function + heart health)
O-3 means that the fat has a double bond at C3
O-6 means that it has one at C6
Cold water fish, almonds, walnuts, leafy veggies, flax, hemp, safflower, + brains, eyes, and testes of animals (which is why those parts were prized by primitive hunter-gatherer people)

16. Cis vs. Trans

17. Trans Fats
Artificially created unsaturated fat, “partially hydrogenated” changes a cis double bond into a trans
Much more stable than unsaturated fats, but still just as cheap
Margarine, shortening, fried food, packaged food
Why are they bad?
The trans bond increases the melting point above room and body temperature, so they are solids
Essentially they act like saturated fats (boooo!)
Make blood platelets sticky = clots and artery blockage
Block the function of good fats by blocking enzymes which convert EFAs into the fats our brain uses
Hurt the barrier around cells so some molecules can enter cells though they normally could not = decreased immune function, allergic reactions, cancers
Interfere with electrical currents
Block functions of prostaglandins which regulate blood pressure, clotting, kidney function, and the immune system
Decrease testosterone and increase abnormal sperm
Correlated to obesity, high cholesterol, heart disease and cancer
Avoid Them!

18. FATS SATURATED UNSATURATED Mono Poly Trans Animal fats Tropical oils
Avocados, Olives, Nuts
Poly
Flax, Hemp, Nuts, Fish, Sunflower, Canola
Trans
Margarine, Shortening + Packaged foods