Alkanes vs. AlkenesAlkanes vs. AlkenesA Stinky Lab Turned into an Un-A Stinky Lab Turned into an Un-Stinky Power Point PresentationStinky Power Point Presentation

What do you think these words What do you think these words mean?mean?

Homologous SeriesHomologous Series

Saturated HydrocarbonsSaturated Hydrocarbons

Unsaturated HydrocarbonsUnsaturated 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

Melting and Boiling PointMelting and Boiling Point

Look at the regular Chem text page 753Look at the regular Chem text page 753 What pattern do you see in boiling point as What pattern do you see in boiling point as

alkanes get more carbons?alkanes get more carbons?

What pattern do you see as molecules get What pattern do you see as molecules get less saturated? less saturated?

More carbons = higher boiling point

Less saturated = more double bonds = lower boiling point… mostly

Melting Point cont.Melting Point cont.

Put these in order of increasing melting Put these in order of increasing melting point:point:

EthaneEthane OctaneOctane ButaneButane 1-Octene1-Octene

EthaneEthane < Butane Butane < 1-Octene1-Octene < OctaneOctane

Waterwith green food

color

SolubilitySolubility

Alkane Alkene

Summary:

Alkanes and Alkenes are both NOT soluble in water. Plus, they are less dense than water.

CombustionCombustion

AlkaneAlkene

Blue Flame

Black SmokeSummary:

Alkanes burn

cleaner than

Alkenes

Alkane <-> AlkeneAlkane <-> Alkene

Alkane Alkane Alkene is called Alkene is called crackingcracking

Alkene Alkene Alkane is called Alkane is called additionaddition

C3H8 heat and Ni catalyst C3H6 + H2

C2H6 + H2 C2H8

Identifying Alkanes/enesIdentifying Alkanes/enes

Alkane + Halogen Alkane + Halogen Haloalkane (slow), Haloalkane (slow), substitutionsubstitution

Alkene + HalogenAlkene + Halogen Haloalkane (fast) this Haloalkane (fast) this is called is called additionaddition

C3H8 + Br2 C3H7Br + HBr

C2H4 + Br2 C2H4Br2

Plain Br2 reference

Plain Br2 reference

Alkane AlkeneAlkane

Alkene

Summary: •Alkenes react quickly with Br2- addition

•Alkanes react slowly + need UV light- substitution

Bromine- Substitution and Bromine- Substitution and Addition ReactionsAddition Reactions

Quick ReviewQuick Review

Alkanes and alkenes are ____ soluble in waterAlkanes and alkenes are ____ soluble in water As # of C increases, melting point ____As # of C increases, melting point ____ As saturation decreases, melting point ____As saturation decreases, melting point ____ Combustion of _____ is cleaner than _____Combustion of _____ is cleaner than _____ Alkanes change into alkenes with _____ and Alkanes change into alkenes with _____ and

__________ Alkenes turn into alkanes with _____Alkenes turn into alkanes with _____

An ____ reacts quickly to decolorize BrAn ____ reacts quickly to decolorize Br22

NOT

increases

decreases

heat

Nickel catalyst

alkanes alkenes

hydrogen

alkene

We need fat in our dietWe need fat in our diet To…To… Absorb shock, warmth, energy, move Absorb shock, warmth, energy, move

electrical/nerve currents, construct electrical/nerve currents, construct membranes, brain function, sex membranes, brain function, sex glands, hormone functionglands, hormone function

Cholesterol tooCholesterol too Can be from food, but our body Can be from food, but our body

makes all we needmakes all we need Hormones, steroids, skin protectant, Hormones, steroids, skin protectant,

antioxidantantioxidant

““Good cholesterol”= HDL, “Bad” = Good cholesterol”= HDL, “Bad” = LDLLDL

Saturated FatsSaturated Fats Animal products + coconut and palm oils, peanuts, butterAnimal products + coconut and palm oils, peanuts, butter Solids at room temperature Solids at room temperature andand body temperature body temperature Can stack up on each other because the structures are floppy, even Can stack up on each other because the structures are floppy, even

form crystal structures (aggregate)form crystal structures (aggregate) Insoluble in waterInsoluble in water

What they can do that’s bad:What they can do that’s bad: Deposit + hardens arteries and increases blood Deposit + hardens arteries and increases blood

pressurepressure Blood clots Blood clots Increase bad (LDL) cholesterolIncrease bad (LDL) cholesterol Avoid

Them!

OilsOilsThis 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

Unsaturated FatsUnsaturated Fats Have a very slight + and – charge, so they repel each other, Have a very slight + and – charge, so they repel each other,

keeping them fluid (liquid at room and body temperature) and keeping them fluid (liquid at room and body temperature) and unable to aggregate like saturated fatsunable to aggregate like saturated fats

Less stable (more likely to oxidize, turn rancid) than saturated fatsLess stable (more likely to oxidize, turn rancid) than saturated fats From 1 to 6 double bondsFrom 1 to 6 double bonds

What they can do to your body…What they can do to your body… MonounsaturatedMonounsaturated

Decrease bad cholesterol and increase good Decrease bad cholesterol and increase good Olive oil, canola oil, avocado, nuts, butterOlive oil, canola oil, avocado, nuts, butter

PolyunsaturatedPolyunsaturated Decrease the bad Decrease the bad Omega fatty acids Omega fatty acids increase brain function increase brain function Cold water fish, almonds, walnuts, leafy veggies, flax, Cold water fish, almonds, walnuts, leafy veggies, flax,

hemp, safflower, + brains, eyes, and testes of animals hemp, safflower, + brains, eyes, and testes of animals (which is why those parts were prized by primitive (which is why those parts were prized by primitive hunter-gatherer people)hunter-gatherer people)

Cis vs. TransCis vs. TransA decent

video

Trans FatsTrans Fats Artificially created unsaturated fat, “partially hydrogenated” Artificially created unsaturated fat, “partially hydrogenated”

changes a cis double bond into a transchanges a cis double bond into a trans Much more stable than unsaturated fats, but still just as cheapMuch more stable than unsaturated fats, but still just as cheap Margarine, shortening, fried food, packaged foodMargarine, shortening, fried food, packaged food

Why are they bad?Why are they bad? They are solidsThey are solids Clots and artery blockageClots and artery blockage CancersCancers Interfere with electrical currentsInterfere with electrical currents

Avoid Them!

FATS

SATURATED

Animal fatsTropical oils

UNSATURATED

Mono

Avocados, Olives, Nuts

Poly

Flax, Hemp,

Nuts, Fish, Sunflower,

Canola

Trans

Margarine, Shortening

+ Packaged

foods