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