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Organic Flashcards

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1
Q

what is crude oil and where does it come from?

A

a finite resource that is found in the Earth’s crust. a mixture of hydrocarbons, mainly alkanes, formed over millions of years from the remains of ancient dead marine organisms.

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2
Q

describe the composition of crude oil

A
  • The carbon atoms in these molecules are joined together in chains and rings
  • each carbon atom is connected to 2 hydrogen atoms
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3
Q

what is the general formula for alkanes?

A

CnH2n+2, where n is the number of carbon atoms in the molecule

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4
Q

names of the first four alkanes

A
  1. methane
  2. ethane
  3. propane
  4. butane
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5
Q

process of fractional distillation in 4 steps

A
  1. heated crude oil enters a tall
    fractionating column, which is hot at the bottom and gets cooler towards the top
  2. vapours from the oil rise through the column
  3. vapours condense when they become cool enough
  4. liquids are led out of the column at different heights
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6
Q

state the names and uses of 5 fuels that are produced from crude oil by fractional distillation

A
  • liquefied petroleum gases- fuel for domestic heating and cooking
  • petrol- fuel for cars
  • kerosene- fuel for aircrafts
  • diesel- fuel for some cars and power stations
  • bitumen- for roads and roofs
  • (Lazy Penguins Keep Drinking Hot Beer.)
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7
Q

3 properties of hydrocarbons with 1-4 carbon atoms

A

gases fraction contains hydrocarbons with one to four carbon atoms
* boiling points below room temperature
* they are very
flammable
* have a low viscosity

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8
Q

3 properties of hydrocarbons with more carbon atoms

A

bitumen fraction contains hydrocarbons with more than 35 carbon atoms. These have:
* boiling points well above room temperature
* are very difficult to ignite
* have a high viscosity

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9
Q

what is the general equation for the complete combustion of hydrocarbon fuels?

A

hydrocarbon + oxygen → carbon dioxide + water

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10
Q

how to write a cracking equation

A
  • The starting compound will always fit the rule for an alkane, CnH2n+2.
  • The first product will also follow this rule.
  • The second product will contain all the other C and H atoms.
  • The second product is an alkene, so it will follow the rule CnH2n.
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11
Q

what happens in cracking?

A

The breaking down of large hydrocarbon molecules into smaller, more useful hydrocarbon molecules by vaporising them and passing them over a hot catalyst.

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12
Q

define saturated

A

A saturated hydrocarbon contains no carbon-to-carbon double bonds, only single bonds.

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13
Q

are alkenes and alkanes saturated or unsaturated?

A

alkanes are saturated, alkenes are unsaturated because unsaturated, because they contain a C=C double bond, which means that they have two fewer hydrogen atoms than the corresponding alkane

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14
Q

define unsaturated

A

An unsaturated compound contains at least one double or triple bond.

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15
Q

describe the test for alkenes

A
  • Alkenes will react with bromine water and turn it from orange/brown to colourless. This is the way to test for a double C=C bond in a molecule.
  • this is because as a result of being unsaturated, alkenes are more reactive than alkanes.
  • Alkenes can take part in reactions that alkanes cannot.
  • For example, ethene molecules can react together to form poly(ethene), a
    polymer.
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16
Q

2 reasons cracking is important

A
  • It helps to match the supply (how much of a fraction an oil refinery produces) of fractions with the demand for them since smaller hydrocarbons are more useful as
    fuels
    than larger hydrocarbons
  • It produces alkenes, which are useful as feedstock (A raw material used to provide reactants for an industrial reaction.) for the petrochemical industry.
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17
Q

first four alkenes

A
  • ethene
  • propene
  • butene
  • pentene
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18
Q

structure of ethene

A
  • C2H4
  • each C has 4 bonds as always
  • but there is one C=C functional group (double bond)
    H H
    C = C
    | |
    H H
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19
Q

structure of propene

A
  • C3H6
  • each C has 4 bonds as always
  • but there is one C=C functional group (double bond)
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20
Q

structure of butene

A
  • C4H8
  • each C has 4 bonds as always
  • but there is one C=C functional group (double bond)
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21
Q

structure of pentene

A
  • C5H10
  • each C has 4 bonds as always
  • but there is one C=C functional group (double bond)
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22
Q

what is a functional group

A

An atom, or group of atoms, that determines the main chemical properties/ typical reactions of an organic compound.

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23
Q

what is complete combustion?

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A

Complete combustion of a hydrocarbon fuel happens when there is a good supply of air. Carbon and hydrogen atoms in the fuel react with oxygen in an exothermic reaction

24
Q

what is incomplete combustion?

Study These Flashcards
A

Incomplete combustion happens when the supply of air or oxygen is poor. Water is still produced, but
carbon monoxide and carbon are produced. Less energy is released than during complete combustion.

25
describe the reaction between an alkene and hydrogen
* hydrogenation * Alkene + hydrogen → alkane * hydrogen is H-H so the C=C double bond is broken to bond with the H-H
26
describe the reaction between an alkene and water
* hydration * Alkene + water (steam) → alcohol * the double C=C bond breaks to bond with the 2 Hs in water (H-O-H) * the O in water bonds with an H
27
describe the reaction between an alkene and halogens
* Alkene + halogen → halogenoalkane * the double C=C bond will break and each of these Cs will bond with one of the two halogen atoms (they come in pairs)
28
what is the functional group of alcohols?
hydroxyl group, -O-H (not to confuse with hydroxide OH-)
29
what is the general formula of alcohols?
CnH2n+1OH
30
what are the first four alcohols and their chemical symbols?
* methanol CH3OH * ethanol C2H5OH * propanol C3H7OH * butanol C4H9OH
31
combustion of alcohols
* ethanol + oxygen → carbon dioxide + water * The alcohols undergo complete combustion to form carbon dioxide and water. * When less oxygen is present, incomplete combustion will occur, producing water and either carbon monoxide or carbon.
32
alcohols reaction with sodium
* sodium + alcohol (ethanol) → sodium ethoxide + hydrogen * 2Na + 2C2H5OH → 2C2H5ONa + H2
33
alcohol's solubility/ dissolving in water (what happens?)
* When the alcohols with the shortest hydrocarbon chains, eg methanol, ethanol or propanol, are added to water, they mix easily to produce a solution. * However, the solubility decreases as the length of the alcohol molecule gets longer, so butanol is less soluble than propanol. * It may not mix easily, and two distinct layers might be left in the container.
34
oxidation of alcohols
* alcohol (ethanol) + oxidising agent → carboxylic acid (ethanoic acid) + water * if ethanol is shown as CH3CH2OH in the balanced equation: * CH3CH2OH + 2[O] → CH3COOH + H2O * Each of the two oxygen atoms provided by the oxidising agent are shown as [O]. * Notice that the left-hand side of the ethanol molecule is unchanged. * The reaction involves the -OH group on the right-hand side.
35
use of methanol
Methanol is used as a chemical feedstock. It is toxic, so it is deliberately added to industrial ethanol (methylated spirits) to prevent people from drinking it.
36
uses of ethanol
Ethanol is the alcohol present in alcoholic drinks. It is also used as a fuel and a solvent.
37
uses of propanol and butanol
Propanol and butanol are also used as solvents and fuels.
38
what is functional group of carboxylix acids?
carboxyl group, -COOH
39
first four carboxylic acids and their chemical formulas
* methanoic acid HCOOH * ethanoic acid CH3COOH * propanoic acid C2H5COOH * butanoic acid C3H7COOH
40
general formula of carboxylic acids
CnH2n+1 COOH
41
structure of methanoic acid
O || H - C | O-H * (C is double bonded to an O, single bonded to another O which is single bonded to an H, and single bonded to an H)
42
structure of ethanoic acid
H O | || H - C - C | | H O - H * (C is double bonded to an O, single bonded to another O which is single bonded to an H, and single bonded to an C which is single bonded to 3 Hs)
43
4 properties of carboxylic acids
they have the typical properties of acids * dissolve in water to form acidic solutions with pH values less than 7 * react with metals to form a salt and hydrogen * react with bases to form a salt and water * react with carbonates to form a salt, water and carbon dioxide
44
describe the reaction between carboxylic acids and alcohols and the functional group of what they form
* alcohol + carboxylic acid → ester + water * e.g. ethanol + ethanoic acid → ethyl ethanoate + water * H from alcohol and H-O from carboxylic acid form water * then the C on the carboxylic acid that is double bonded to an O and single bonded to a C, single bonds to the O on the alcohol to join the alcohol and acid together * esters functional group is -COO- (shows as O-C=O in structure)
45
functional group of carboxylic acids
-COOH shown as O=C-O-H
46
reaction between carboxylic acids and carbonates
* acid + metal carbonate → salt + water +carbon dioxide * e.g. ethanoic acid + copper carbonate → water + carbon dioxide + copper ethanoate
47
how do you draw a repeating unit of a polymer (polymerisation of a monomer)?
* turn the double bond (C=C) into a single bond (C-C) * put the whole thing in large square brackets * draw long bond lines on either side going through both brackets
47
48
how can alkenes be used to make polymers by addition polymerisation?
when the double bonds of the alkene molecules are broken and new single bonds are formed between the carbon atoms of adjacent monomers. this results in the formation of a long chain of carbon atoms, or polymer.
49
describe the process of condensation polymerisation and what it is
* Chemical reaction in which 2 different monomers (small molecules) join/ react together to produce a polymer (larger molecule) with the elimination of a small molecule such as water (H2O) * In addition polymerisation, the monomers must have a C=C double bond. * However, in condensation polymerisation, the monomers do not need a C=C double bond but they do need two functional groups. * We can simplify the equation by using symbols to represent the carbon chain in the middle of each of the two monomers * ■ and ♦ can be used to replace -CH2-CH2-
50
what functional groups do amino acids have?
* they have at least two functional groups. * all amino acids contain the -NH2 group and also the carboxylic acid group -COOH.
51
how are amino acids polymerised and what do they make?
* by condensation polymerisation in cells * so for every monomer which is added to the growing polymer chain, one molecule of water is also produced. * amino acids make polypeptides and proteins by this
52
do the same amino acids need to be combined in a chain to produce proteins?
no, different amino acids can be combined in a chain to produce proteins
53
what is DNA?
a large molecule of two polymer chains made from four different monomers called nucleotides in the form of a double helix
54
3-4 naturally occuring polymers
* DNA * proteins * starch and cellulose
55
describe proteins (as polymers)
Biological polymers made inside cells. They are made from amino acid monomers and have a huge range of roles inside living things. For example, all enzymes are made from proteins.
56
describe starch and cellulose (as polymers)
* Biological polymers which are made by plants. * The monomers for both starch and cellulose are sugar molecules. * Starch is used by plants as a way of storing energy as a complex carbohydrate. * Cellulose is used to make the strong cell wall which gives plant cells (and therefore plants) strength.
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