Chemistry LC4
Grade 12
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chapter 18 notes
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Section Review Questions on page 639
1. What are the major sources of hydrocarbons? Where are they found?
fossil fuels such as coal, natural gas, and petroleum; deep in Earth, under the ocean
2. Halogen molecules such as Br2 can be added to double bonds in a reaction
similar to hydrogenation. Draw the structure of the product that forms when Br2
is added to propene
.
3. Storage of Hydrocarbons Would it be more important to store octane or
pentane in a tightly sealed bottle at a low temperature? Why?
Pentane. Because it has a shorter carbon chain than octane, it has a lower boiling point and will be
more likely to vaporize away.
Section Review Questions on page 647
1 .Explain
why organic compounds with similar structures often have similar uses.
Uses depend on properties, which depend on structures.
2. Distinguish between an
aldehyde and a ketone.
Ketones have a carbonyl group bonded between two hydrocarbon groups. In an aldehyde, one of the
hydrocarbon groups is replaced by a hydrogen atom.
3. Redraw the following structure of thyroxine, a thyroid hormone. Circle and name each type of
functional group present.
One hydroxyl group, four halogen (I) atoms, one ether group, one amino group, one carboxyl group, two
benzene rings
4.Inferring Explain why alkenes and alkynes contain functional groups but are not substituted
hydrocarbons.
. Alkenes and alkynes contain multiple bonds, which are functional groups. Substituted
hydrocarbons contain groups of atoms in place of a part of the hydrocarbon. Alkenes and alkynes do not
have any substitute groups.
5.Antifreeze Ethylene glycol, used as an antifreeze in car radiators, has two hydroxyl groups, as
shown below.What can you infer about the boiling point, freezing point, and solubility in water of
this compound from its structure?
The two hydroxyl groups make ethylene glycol very polar. Therefore, it could be
expected to have a high boiling point and low freezing point, and be soluble in water.
Section Review Page 661
Identify the repeating unit that appears in each of the following polymers.
2. Draw the structure of the polymer that will be formed from each of the monomers shown.
a) CH2=CHCl
b) NH2CH2COOH
c) CH2=CHOH
3.Compare and contrast addition and condensation polymerization reactions.
Addition reactions involve adding monomers together by using electrons
present in double bonds to make new single bonds without releasing water. Condensation
reactions result in release of a small molecule, usually water, every time two monomers
combine.
4.Can a polymer be made from alkane monomers by addition polymerization? Explain.
Polymers cannot be made from alkanes by addition polymerization because this process
requires that the monomer have a double or triple bond. Alkanes have neither.
5. Paints usually contain three components: a binder that hardens to form a continuous film,
a colored pigment, and a volatile solvent that evaporates. In latex paints, one of these
components is a polymer. Use what you have learned about polymer properties todecide
which of the three most likely is a polymer. Explain.
The binder will most likely be a polymer because it hardens into a film. Most polymers are
not volatile, and most pigments are smaller molecules.
Assessment Questions page 662-664
1List four natural and four synthetic polymers
Natural: cellulose, starch, DNA, protein
Synthetic: nylon, Teflon, Bakelite, PVC
2. What molecule is usually released when monomers combine in a condensation reaction?
usually water.
3. Describe how the boiling points of alkanes change as chain length increases.
Boiling points increase as chain length increases in the
alkanes.
4. Why is there no compound named 4-methylhexane? What is the correct name for
this compound?
IUPAC rules require that positional numbering begin at the end of the molecule
that gives the lowest number for the added group.
A compound named 4- methyl hexane is identical to 3-methylhexane.
5.
8. Copy the following structure of penicillin G, an antibiotic. Circle all the functional groups
in the molecule.
Ans; aromatic ring, two amide groups, carboxylic acid group, thioether (—S—) group
9. Draw the structure of an ether, where R is —CH3 and Ris—CH2CH3.
Ans;