hydrocarbons: & polymers:. a hydrocarbon is a compound that is mostly made of hydrogen and...

Hydrocarbons:Hydrocarbons:

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Polymers:Polymers:

A Hydrocarbon is a compound that is mostly made of hydrogen

and carbon atoms. Hydrocarbons may be linear or branched,

cyclic (ring shaped) or polymers. (see below)

- All hydrocarbons are organic compounds.

Organic Compound = a compound that contains carbon atoms.

– (Exceptions are CO2 , CO, diamond, graphite, etc.)

CombustionCombustion Of Hydrocarbons Of Hydrocarbons

- Combustion is a type of chemical reaction.-Hydrocarbon reacts with oxygen gas (burns) and forms carbon dioxide and water vaporEx. C2H6 + O2 CO2 + H2O *Balance the equation!

A “polymer” is something made of many units.

“mer” = each link in the chain or single unit.

(monomer) mono = “one”

(polymer) poly = “many”

- Many monomers bond together to form a long chain, called a “polymer”.

-A single Covalent bond shares 2 electrons, and hold polymers together.

- when hydrogen atoms bond to carbon atoms, the compound is called a “hydrocarbon”.

Types ofTypes of MonomersMonomers::

POLYMERS can be Natural or Synthetic • Natural is made by nature.

• commonly made by plants.

• Commonly made of the elements; – C, H, O, + N, F, P, S, Cl, Br, & I

• Uses = cotton, rubber, starch, cellulose,

fiber, glycogen.

• Synthetic means “man made”

or not found in nature.

• UsesUses = plastics, rubber, carpet

fibers, styrofoam

speaking of plastics….

High Density & Low Density Plastics

• High density plastics are stronger, with a greater tensile strength and more

abrasion resistant than low density plastics.

• High density plastics examples = black construction bags

• Low density plastics examples = grocery bags.

LDPE– More flexible and soft– Not as strong– More branches

HDPE -long chains

-more rigid

-can be regularly packed

Recycling plastics… What does that little number in the triangle mean?

• Resin code- identifies the type of plastic used

Thermoplastics

• Don’t undergo a chemical change

in composition when heated

• Can be re-melted and reshaped again and again

• Are recyclable

Thermosetting plastics

• Can melt and take shape only once

• Heat (or chemicals) causes a cross-linking process and forms a rigid plastic

• Can’t be recycled but can be reused

a. Weak bonds; molecules slide past each other when heated

b. Stronger (cross-linked) bonds; rigid structure even when heated

Vulcanization

• Is an example of thermosetting

• Sulfur is added to rubber and is then heated

• Cross-links form

• Vulcanized rubber is durable and elastic (think car tires)

Biopolymers

• Produced by living things

• Common example is cellulose (in cotton, wood, etc.)

• Can be used for plastics

-biomass from crops can be used to produce polyethylene

Play the game!

• Cut out the slides that follow and place them into the following categories:

• Natural polymer

• Artificial (manmade) polymer

• Wool (from the protein keratin, a polymer)

• Glucose and Cellulose

– The polymer cellulose is made up of the monomer glucose. Each year, plants synthesize over 1 trillion tons of cellulose, making it one of the most common naturally occurring polymers

Glucose/carbohydrates

• Lipids (fats/vegetable oils)Fatty acids make up saturated/unsaturated fats

Amino acids/proteins

Hydrocarbon gases used for fuel

• Nylon

• Kevlar

• Vulcanized rubber

• Polyethylene (from petroleum)

• Polystyrene