Download Pre DP Chemistry 2 Organic Chemistry

Pre DP Chemistry 2
Organic Chemistry
Teacher: Annika Nyberg
[email protected]
http://www.ck12.org/ngss/middle-school-physical-sciences%2Fmatter-and-its-interactions
Content
1. Introduction
2. Hydrocarbons
3. Functional groups
4. Alcohols and phenols
5. Aldehydes
6. Ketones
7. Carboxylic acids, Acid -base reactions
8. Esters
9. Amines
10. Fats, Proteins, Carbohydrates
11. Dilution of solutions
Revision
Assessment
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Exam: 70 %
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Quiz1: 10 %
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Quiz2: 10%
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Project: 10%
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Quiz 11.2.15: Naming hydrocarbons
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TEST 27.3.2015
BBC News: Complex organic molecule found
in interstellar space
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Science reporter Michael
Eyre: ”Scientists have
found the beginnings of
life-bearing chemistry at
the centre of the galaxy.”
https://www.youtube.com/watch?v=aqvTzhtT4S0
1. Introduction
1.1 Carbon is a unique element
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Carbon atoms can form long chains that are linked by
single, double and/or triple bonds.
Carbon and hydrogen are the basic building blocks in
organic compounds.
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Other elements can be present in organic compounds
as well, such as oxygen, nitrogen, phosphorus,
halogens (F, Cl, Br, I) or sulfur.
1.2 Organic compounds
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Every living organism is made of organic compounds and
the organic compounds are all around you:
- proteins (that make up your hair, skin and muscles)
- DNA (controls your genetic heritage)
- the food you eat
- the clothes you wear
- the medicines you take
Demo: sucrose + sulfuric acid
1.3 The carbon cycle
https://www.youtube.com/watch?v=aLuSi_6Ol8M&list=PL8dPuuaLjXtPHzz
YuWy6fYEaX9mQQ8oGr&index=47
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http://www.youtube.com/watch?v=nzImo8kSXiU
1.4 Crude oil
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Crude oil was formed over millions of years ago when the
remains of animals and plants were trapped under layers
of rock.
Crude oil is a complex mixture of many different organic
compounds, mainly alkanes.
1.5 Refining
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In an oil refinery the alkanes are separated (according
to boiling point) by fractional distillation.
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The various fractions, with different physical
characteristics, are used in a wide variety of
circumstances, mainly as fuels.
Pearson etext topic 10 fractional distillation of crude oil
2. Hydrocarbons
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A hydrocarbon is an organic compound that
consists of ONLY carbon and hydrogen.
The carbon atoms are bonded together to form
the "backbone" to which the hydrogen atoms are
bonded.
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There are at least 6 million different organic compounds,
all with their own physical and chemical properties.
In order to study all these organic compounds, they are
categorized into ”families” according to their structures.
Members of these families have similar chemical
reactivities.
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Straight chain hydrocarbon:
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Branched hydrocarbons:
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Cyclic hydrocarbons:
2.1 Ways to describe organic compounds
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Empirical formula: The simplest whole number ratio of
the atoms in a molecule. CH2O
Molecular formula: The actual number of atoms in a
molecule.
C6H12O6
Structural formula: How the atoms are bonded to each
other in a molecule.
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Full structure
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Condensed structure
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Skeletal (line-bond) structure
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Molecular model
CH3CH2CH2CH2CH2CH3
2.2 Isomers
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Compounds with the same molecular formula but with
different structures.
Draw the three different structures of C5H12 and the five
different structures of C6H14
C8H18
C9H20 has 35 isomeres
C20H42 has 366 319 isomeres
2.3 Alkanes
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Saturated (= only single bonds between
the carbons)
Reactivity
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Alkanes are stable under most conditions, because of
strong C-C and C-H bonds and low polarity.
Combustion:
General formula CnH2n+2
Boiling point of alkanes
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The boiling points increases as the carbon chain gets
longer.
2.4 Alkenes
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Unsaturated (double bond/bonds).
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The double bond reacts in addition reactions.
Addition reaction
Alkene test
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Alkenes readily undergo addition reactions, whereas
alkanes will not.
Polyethene
2.5 Alkynes
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Unsaturated (triple bonds).
2.6 Aromatic Hydrocarbons
benzene
2.7 Halogenated hydrocarbons
Chloroform
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Chloroform has been used by criminals to knock out,
their victims.
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Homework: Read chapter 6 (Cliff Notes) ppg. 53-64.
2.8 Naming hydrocarbons
Prefix
- Parent
Where are the substituents?
- Suffix
How many carbons?
What family?
e.g. 3-methylhexane
What is the name of the molecule?
The systematic name of an hydrocarbon is
obtained using the following rules:
1. Determine the number of carbons in the longest
continuous carbon chain. This chain is called the
parent hydrocarbon.
Number of C
parent
1
2
3
4
5
6
7
8
9
10
meth
eth
prop
but
pent
hex
hept
oct
non
dec
2. The functional group is described by a ending (=
suffix) to the name.
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Single bond: -ane
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Double bond: -ene
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Triple bond: -yne
3. The name of any alkyl substituent (= the branches) is
cited before the name of the parent hydrocarbon.
Indicate the position with a number.
● Give the substituent as low a number as possible.
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Alkyl group
Name
-CH3
methyl
-CH2CH3
ethyl
-CH2CH2CH3
propyl
-CH2CH2CH2CH3
butyl
-CH2CH2CH2CH2CH3
pentyl
4. If more than one substituent is attached to the parent
hydrocarbon, the chain is numbered in the direction that
will result in the lowest possible number in the name of
the compound.
5. If a compound contains two or more identical
substitutes, the prefixes “di,” “tri,” and “tetra” are used.
2,3-dimethylbutane
3. Functional groups
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A functional group is the active group in an organic
compound.
It reacts easily and thereby determines the
characteristics of the compound.
All compounds that have the same functional
group form their own homologous series.
A molecule can have more than one functional
group.
Ex. Identify the functional groups in the LSD molecule.
Ex. Identify and name the functional groups in the heroine
molecule.
Ex. Identify the organic compound(s) that are
a) alcohols b) amines c) aldehydes.
Project about an organic compound/family of
compounds
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In pairs
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Prepare a 10 min presentation
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Project presentations:
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–
11.3.2015
–
13.3.2015
~10-20% of the course grade
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Name (trivial & systematic name)
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Structural formula, molecular formula, molar mass
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All functional groups named
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Melting point, boiling point
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Appearance
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Chemical properties and reactivity (reactions)
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Hazards/Safety
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History
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Production of the substance
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Biological properties
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Occurence in nature
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Usage
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Occurence in popular culture (litterature,
movies)
A short youtube about 2min.
4. Alcohols and Phenols
4.1 Alcohols
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contain one or more polar hydroxyl group:
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The more hydroxyl groups, the stronger the hydrogen
bonds between the molecules → higher viscosity and
higher boiling points.
4.2 Phenols
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When the hydroxylgroup
is attached directly to a
benzene ring, the group
is called a phenyl
hydroxyl group.
These compounds are
not classified as
alcohols,but as phenols.
Phenols are weak acids.
●
Draw structures that meet the following descriptions:
a) Two isomers with the formula C4H8O2
C3H6O
4.3 Naming
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Alcohols are also classified as primary, secondary or
tertiary, depending on the location of the
hydroxylgroup.
C-
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If there are two or more functional groups in a molecule, the
order is:
carboxylic acid > ketone/aldehyde > alcohol > amine > halide
4.4 Combustion
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When an organic compound undergoes complete
combustion, the products are always CO2 and H2O.
Ex.
Write the balanced equation for the combustion of
ethanol
C2H6O (l) +3O2 (g) → 3H2O (g) + 2CO2 (g)
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What mass of glucose must be fermeted to give 5.oo
kg of ethanol?
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Calculate the amount of ethanol in moles (nethanol)
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Calculate the amount of glucose in moles (= ½ nethanol)
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Calculate the mass of glucose.
4.5 Oxidation of alcohols
primary alcohol
aldehyde
secondary alcohol
carboxylic acid
ketone
4.6 Mass percent
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Ex. Calculate the mass-% of sugar in a solution that
contains 50 grams sugar in 210 grams of water.
4.7 Volume percent
Ex. Calculate the volume of pure
ethanol in a bottle of wine (750 ml)
with a 12 volume-% of ethanol.
Ex. Calculate the volume of pure
acetic acid in a diluted vinegar
solution with 10 percent of acetic
acid by volume .
5. Aldehydes
Aldehydes from alcohols
MnO2
(bitter almond oil)
Formaldehyde:
- TOXIC
- a gas at room tempertures (bp. -19º
C)
- colorless and has a characteristic
pungent, irritating odor
- used for preservation of biological
specimens
Vanillin
Anisaldehyde
6. Ketones
Acetone:
- colorless liquid
- important solvent
- used in nail polish removers
and as paint thinner
7. Carboxylic Acids
ethanoic acid
butanoic acid
(vinegar)
(sour butter)
hexanoic acid
(dirty gym socks)
7.1 Condensation reaction
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Carboxylic acids react with
alcohols to form esters:
7.2 Acid-base reactions
ethanoic acid
oxalic acid
Acids
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An acid donates protons (H+) to a base that accepts
protons in a chemical reaction.
A base must have an extra nonbonded electron pair that it
can share with the proton.
An aqueous solution becomes acidic when an acid
donates a proton to a water molecule, because an
oxonium ion (H3O+) is produced.
8. Esters
9. Amines
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Amines are derivatives of ammonia, where 1, 2 or 3
hydrogens have been displaced by carbon chains.
Amines are therefore classified as primary, secondary or
tertiary.
Ex. State whether the following amines are primary, secondary or tertiary.
(Unpleasant odour from
the body of dead
animals)
Bases
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An aqueous solution becomes alkaline (basic) when a
base acceptes a proton from a water molecule.
A hydroxide ion (OH-) is produced:
The reaction of amines and water
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Amines are bases and react with water to produce
hydroxide ions:
Neutralization
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A chemical reaction between an acid and a base to
produce a salt and water:
9.1 The neutralization reaction of amines with acids
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The fishy odor of di- and trimethylamines dissapears if
they are neutralized with citric acid or ethanoic acid.
The pH-scale
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For every billion of water
molecules two are ionized:
8.1 Fats
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Fats and oils are large esters, as they form when
glycerol and three fatty acids (= carboxylic acids with
long carbon chains containing an even number of
carbon atoms between 12 and 20) undergo
condensation reaction:
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The three fatty acids need not be the same. A given fat
or oil is usually a complex mixture of esters of different
fatty acids.
Example of a natural triglyceride with three different fatty acids. One fatty acids is
saturated (blue highlighted), another contains one double bond within the carbon
chain (green highlighted). The third fatty acid (a polyunsaturated fatty acid,
highlighted in red) contains three double bonds within the carbon chain.
8.2 Saturated fats
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The fat is saturated if the fatty acids only have single
carbon-carbon bonds in the chain.
Animal fats are saturated fats and are solids in room
temperature.
8.3 Unsaturated fats
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Vegetable fats are unsaturated fats as they consist of fatty
acids with double/triple bonds.
Vegetable fats are often liquids in room temperature,
because of the double bonds in their structure. They
cannot be tightly packed.
9.2 Amino acids
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Amino acids contain two functional groups: a basic
amino group and an acidic carboxyl group.
9.3 Peptide bond
9.4 Proteins
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All proteins are made up of many amino acids linked
together into a long chain.
The sequence in which amino acids are bonded
together determine only the primary protein structure.
The large molecule then folds and bonds with other
protein molecules to form the final protein.
Structure of proteins
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All proteins are made
up of many amino
acids linked together
into a long chain (more
than 50 amino acids) =
polypeptides.
Primary structure: the number and sequence of the
aminoacids in the polypeptide chain.
Secondary structure: The way in which the chain of
amino acids folds itself due to intramolecular hydrogen
bonding.
Tertiary structure: Interactions between the sidechains to give the protein its threedimensional shape.
Quaternary structure: Separate polypeptide chains
that interact together to give a more complex structure.
Proteins occur in every living organism
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Keratine in skin and fingernails
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Spider web
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Enzymes
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Catalysts in the synthesis of DNA
9.5 Protein denaturation
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A small change in temperature or pH will disrupt the
tertiary structure (the weak intermolecular bonds
between the chains) and cause the protein to become
denatured.
The primary structure remains intact (the covalent
bonds are not affected), but the protein unfolds from
its well defined shape to a randomly shape.
10. Carbohydrates
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Carbohydrates are our main source of energy.
The larger the molecule, the longer it takes for our
bodies to break it down.
Most of the simple carbohydrates taste sweet.
10.1 Monosaccharides
Glucose
Fructose
Galactose
Straight-chain and ring structural formulas
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Monosacharides contain a carbonyl group (C=O) and
at least two –OH groups
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Empirical formula: CH2O
Common isomers of C6H12O6
10.2 Disaccharide
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Two monosaccharides, linked together.
Sucrose (table sugar) is a disaccharide made up of
one glucose molecule linked to one fructose molecule.
10.3 Polysaccharide
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Cellulose is a polysaccharide made up of several
thousand glucose molecules linked together.
Every living organism
contains carbohydrates:
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Sugar and starch in food
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Cellulose in wood, paper and cotton
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Carbohydrates are synthesized by green plants during
photosynthesis:
11. Dilution of solutions
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Ex. If 25,0 ml of 0,56 M H2SO4 is diluted to a volume of
125 ml, what is the molarity of the resulting solution?
Ex. To what volume must 50,0 ml of 1,50 M HCl be
diluted to produce 0,200 M HCl?
Ex. How would you prepare 1,00 l of a 0,50 M solution
of H2SO4 from concentrated (18 M) sulfuric acid?