Topic 8: Polymers and Plastics Flashcards
What is an isotope?
An atoms with the same amount of protons and electrons, however a different number of neutrons.
What is a isomer?
An atom with the same molecular formula, different displayed formula. (different saturated formula)
What is a hydrocarbon?
A molecule that contains hydrogen and carbon only.
What is the homoglegeus seris?
A series of hydrocarbons that have similar chemical properties and a trend in physical properties.
What does UNsaturated mean?
That the atom contains a double bond.
Propane + oxygen =
carbon dioxide + water
C3H8 + 5O2 =
3CO2 + 4H2O
What is Cracking?
Cracking can be used to produce smaller and more useful molecules from larger alkanes.
What is the general formula for the Alkenes?
CnH2n
Fractional distillation of crude oil produces…….
more long chain hydrocarbons than can be used directly and fewer short-chain hydrocarbons than are required.
Why do we want to crack larger molecules of fractional distillation?
Because we need the smaller are more useful molecules. Larger molecules are more useless; they have higher boiling points etc.
Method for cracking parafin oil to ethene?
1) set up apparatus as shown in diagram (Page 21)
2) gently heat the ceramic catalyst, then heat the decane.
3) collect 2-3 test tubes full of gas (discard the first one)
4) test for the presence of the alkene.
How do you test for the presence of an alkene?
Bromine Water Test: addition of Br2 across a double bond. It should go orange/brown to colorless. (Diagram on Page 22).
Isomers of Pentene C5H10?
BOOK PAGE 23
Making Alkenes: Dehydration?
starting material = alcohol
products = water + alkene
catalyst used Al2O3
(Renewable, ethanol produced by fermentation.)
Making Alkenes: Cracking?
starting material = large alkane products = alkene +smaller alkane catalyst = aluminium oxide. Temp = 600-700 degrees. (non-renewable (alkanes sourced from crude oil)).
What are monomers?
Individual building blocks of the polymer.
Examples of monomers?
Example 1) Diagram A (page 27) = monomers all the same.
Example 2) Nylon, diagram B (page 27) = different monomers.
What are polymers?
Many monomers that are joined together to give a larger chain.
Examples of polymers?
Example A) alkenes = addition polymers
The double bond can break to form links to other alkene monomers.
Example B) Carboxylic acids + alcohols = condensation polymers. Formation of each link gives out 1 water molecule.
Polymerization of addition polymers (Ethene)?
Page 28: C2H4 + C2H4 + C2H4 = C6H12 Monomer: ethene Polymer Poly(ethene)
Addition polymer Table: Ethene: Repeating unit: Uses?
Ethene: Poly(ethene): Plastic bags
Addition polymer Table: Propene: Repeating unit: Uses?
Propene: poly(propene): Bottles & packaging
Addition polymer Table: Chloethene: Repeating unit: Uses?
Chloroethene: poly(chloroethene)/polyvinylchloride/PVC: Windows frames & pipes.
Addition polymer Table: Phenylethene: Repeating unit: Uses?
Phenylethene: poly(phenylethene)/polystyren: Insulating cups / boxes
Addition polymer Table: tertraflurorthene: Repeating unit: Uses?
tertraflurorthene: poly(tertraflurorthene)/Teflon: non-stick cooking equipment.
Bromination of Methane: Halogenation?
Is the replacement of one or more hydrogens in an organic compound by halogen atoms.
- When methane is reacted with chlorine, the products of the reaction depend on wether there is an excess of methane or of chlorine.
- If there is an excess of methane it forms chloromethene and hydrogen chloride.
Bromination of Methane: Word equation(Excess of methane)?
methane +> chlorine = chlormethane + hydrogen chloride.
Bromination of Methane: Word equation(Excess of chlorine)?
methane +> bromine = bromomethane +hydrogen bromide
Bromination of Methane: Excess of chlorine?
if there is an excess of chlorine then a mixture of products are formed. Chlorine replaces up to 4 of the hydrogen atoms.
Bromination of Methane: Symbol equation (Excess of chlorine)?
CH4(g) + Br2(g) = CH3Br(g) + HBr(g)
Bromination of Methane: Structural formula (Excess of chlorine)?
Page 30.
Condensation polymers: Nylon: How is it made?
Nylon is made from two different monomers, when they react together a small molecule is eliminated (often water - hence the name condensation polymer). Note that there is a water molecule produced each time a new link is formed. Page 32.
Thermoplastics?
Strands are not linked and that plastic is more flexible and it can be melted and remolded.
Thermoset?
Strands are cross-linked, plastic is harder and is difficult to remold.
Plastic used for water pipes?
Polyviynalchloride.
Two changes that occur in the formation of an addition polymer from its monomers?
- many monomers join to make a polymer.
- Double bond is broken to make more single bonds.
Reason why addition polymers do not biodegrade easily?
- They have strong forces of attraction between atoms.
