C7: Organic chemistry Flashcards

1
Q

what is crude oil? is it finite?

A
  • a mixture of compounds
  • a fossil fuel consisting of the remains of ancient biomass
  • finite resource - cannot be replaced as it is used up
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2
Q

What is a hydrocarbon?

A
  • a compound made up exclusively of hydrogen and carbon atoms
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3
Q

What are alkanes and their formula?

A

Saturated hydrocarbons of a general formula
CₙH₂ₙ₊₂

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4
Q

what is a homologous series ?

A
  • Series of compounds with the same:
  • general formula,
  • functional groups
  • and similar chemical properties
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5
Q

Describe the combustion of hydrocarbons

A
  • exothermic reaction occurs when hydrocarbons are reacted with oxygen
  • complete combustion produces carbon dioxide and water ( carbon and hydrogen atoms are completely oxidised
  • incomplete combustion produces carbon or carbon monoxide and water
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6
Q

Describe the 3 physical properties of alkanes

A
  • boiling points and viscosity increase as molecules get bigger
  • volatility and flammability decrease as molecules get bigger
  • poor reactivity
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7
Q

define ‘cracking’?

A

when large hydrocarbons are thermally broken down into smaller and useful molecules

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8
Q

What type of reaction is cracking?

A

Thermal decomposition

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9
Q

what are the two types of cracking ?

A
  • catalytic cracking: reactant heated to vapour passed over a hot catalyst
  • steam cracking: heated to vapour , mixed with steam and heated to high temperatures
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10
Q

How are the products of cracking used?

A

The products are alkanes and alkenes
- used as polymers and starting materials for synthesis

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11
Q

Explain how fractional distillation of crude oil takes place

A
  • Crude oil is heated and vapourised
  • vapour rises up the fractionating column
  • the column is hotter at the bottom and cooler at the top
  • Hydrocarbons cool as they go up the column and condense at different heights, as they have different boiling points
  • large molecules , high boiling points - at bottom
  • small molecules , low boiling points - at the top
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12
Q

What is an alkene

A
  • unsaturated hydrocarbon
  • contains a C=C bond
  • general formula for alkenes is CₙH₂ₙ
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13
Q

What is the test for alkenes?

A
  • Add bromine water
  • Colour change occurs from orange to colourless
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14
Q

Describe the combustion of alkenes

A
  • they burn with smoky flames due to incomplete combustion
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15
Q

What are the reaction conditions for
addition polymerisation?

A

●High temperature
● High pressure
● Titanium catalyst

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16
Q

State the differences
between addition and condensation polymerisation

A
  • In addition polymerisation, only one product is formed whereas in condensation polymerisation two different products are formed (the polymer and a small molecule)
  • Condensation polymerisation involves
    monomers with 2 different functional group
    whereas addition polymerisation involves just 1
    functional group
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17
Q

Describe the three addition reactions of alkenes and their requirements

A
  • with hydrogen: hydrogenation ; requires a higher temperature and a nickel catalyst
  • with steam - hydration ; requires high temperature, pressure and concentrated phosphoric acid as a catalyst
  • With Br₂/Cl₂/I₂ - addition of halogens
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18
Q

What is an alcohol?

A
  • an organic compound that contains an -OH functional group
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19
Q

State the names and chemical formulae of
the first 4 members of the homologous series
of alcohols

A

● Methanol (CH₃OH)
● Ethanol (C₂H₅OH)
● Propanol (C₃H₇OH)
● Butanol (C₄H₉OH

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20
Q

State the structural formula for the first 4
members of the homologous series of
alcohols

A

● Methanol – CH₃OH
● Ethanol – CH₃CH₂OH
● Propanol – CH₃CH₂CH₂OH
● Butanol – CH₃CH₂CH₂CH₂OH

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21
Q

State characteristics of the first 4 alcohols

A
  • dissolve in water to form a neutral solution
  • react with sodium to form hydrogen and sodium ( ethoxide eg)
  • burn in oxygen
  • react with carboxylic acids in presence of acid catalyst to form esters
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22
Q

What happens when
an alcohol reacts with an
oxidising reagent?

A

A carboxylic acid is produced

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23
Q

State 3 uses of alcohols

A

● Solvents
● Alcoholic drinks
● Fuels

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24
Q

State the conditions required for fermentation of glucose and state the equation of the reaction

A
  • 30℃
  • aqueous solution of the glucose
  • absence of air
  • yeast added
    C₆H₁₂O₆ → 2C₂H5OH + 2CO₂
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25
Q

How is ethanol made
from glucose?

A

Ferment sugar solutions (glucose) using yeast

26
Q

What is observed
when ethanol burns in
air?

A

A clean blue flame

27
Q

What is the word
equation for the
complete combustion of
ethanol?

A

Ethanol + oxygen → carbon dioxide + water

28
Q

What is observed
when alcohols react with
sodium metal?

A

The sodium effervesces (gives off bubbles of gas

29
Q

What is the word
equation for the reaction
of sodium with ethanol?

A

Sodium + Ethanol Sodium ethoxide + Hydrogen

30
Q

What happens when
alcohols are added to
water?

A

They mix and a neutral solution is produced

31
Q

What is the word equation for the reaction
of sodium with ethanol?

A

Sodium + Ethanol Sodium ethoxide + Hydrogen

32
Q

What is the balanced
chemical equation for
the complete
combustion of ethanol?

A

C₂H₅OH + 3O₂ 2CO₂ + 3H₂O

33
Q

What are carboxylic acids?

A

organic compounds that contain a COOH functional group

34
Q

State 4 characteristics of carboxylic acids

A
  • dissolve in water to form an acidic solution ( contains H+ ions)
  • react with metal carbonates to form carbon dioxide , the salt and water
  • react with alcohols with a sulfuric acid catalyst to produce esters
  • react with metals to give off hydrogen gas
34
Q

State 4 characteristics of carboxylic acids

A
  • dissolve in water to form an acidic solution ( contains H+ ions)
  • react with metal carbonates to form carbon dioxide
  • react with alcohols with an acid catalyst to produce esters
  • react with metals to give off hydrogen gas
35
Q

What type of acid is a carboxylic acid?

A
  • it is a weak acid
36
Q

Explain why carboxylic acids are weak acids?

A
  • they are partially dissolved in water , thus the pH of a carboxylic acid in solution is not as low as a solution of a strong acid of the same concentration
37
Q

State the names and
chemical formulae of
the first 4 members of
the homologous series
of carboxylic acids

A

● Methanoic acid (HCOOH)
● Ethanoic acid (CH₃COOH)
● Propanoic acid (C₂H₅COOH)
● Butanoic acid (C₃H₇COOH

38
Q

What is the structural
formula for the first four
members of the
homologous series of
carboxylic acids?

A

● Methanoic acid - HCOOH
● Ethanoic acid - CH₃COOH
● Propanoic acid - CH₃CH₂COOH
● Butanoic acid – CH₃CH₂CH₂COOH

39
Q

What happens when
carboxylic acids dissolve
in water?

A

An acidic solution forms

40
Q

What is formed
when a carboxylic acid
reacts with a metal
carbonate?

A

A salt, carbon dioxide and water

41
Q

State the word
equation for the reaction
between ethanoic acid
and sodium carbonate

A

Ethanoic acid + Sodium carbonate ➝ sodium
ethanoate + water + carbon dioxide

42
Q

What is an ester and how is it formed?

A
  • an organic compound containing a -COO- functional group , formed from carboxylic acids and alcohol in the presence of a sulfuric acid catalyst
  • they have a fruity smell
43
Q

State the word
equation for the reaction
of ethanoic acid with ethanol in the presence
of sulphuric acid catalyst

A

Ethanoic acid + Ethanol ⇋ Ethyl ethanoate + wate

44
Q

State 2 properties of
esters

A

● Pleasant smell
● Volatile (low boiling point)

45
Q

State 2 uses of esters

A

● Perfumes
● Food flavourings

46
Q

what is a polymer

A
  • a polymer is a long chain molecule which is made up of lots of smaller molecules joining together ( monomers
47
Q

How do molecules containing C=C bond form polymers?

A

C=C bonds open up and many smaller molecules ( monomers) join together to form a chain

48
Q

Give three examples of addition polymers and their uses.

A

Polyethene : plastic bags
(Poly)tetrafluoroethene (PTFE) : teflon surfaces, for use in non stick kitchenware
(Poly) chloroethene (polyvinylchloride, PVC) - water pipes

49
Q

What is a repeating unit of a polymer?

A

It is a smaller structure which, upon numerous translations, yields the structure of the polymer

50
Q

How many different
functional groups does
an amino acid molecule
have?

A

two

51
Q

What are the two
different functional
groups in a molecule of
amino acid?

A

● -COOH
● -NH2

52
Q
  1. What type of
    reaction occurs for
    amino acids to produce
    a polypeptide?
A

Condensation polymerisation reaction

53
Q

What is an amino acid?

A
  • it is an organic compound that contains both a carboxylic acid functionality ( COOH) and an amine functional group (-NH2)
54
Q

How do amino acids make proteins?

A

through numerous condensation polymerisation reactions; proteins are polymers made of amino acids ( monomers)

55
Q

what are polypeptides?

A
  • made up of condensation polymerisation of amino acids , but are shorter than proteins.
56
Q

What are carbohydrates?

A
  • they are organic molecules made of C, H and O.
  • Polymers made of glucose monomers
  • their structures differ in the way the glucose molecules are joined together.
57
Q

What is DNA?

A

DNA is a material that makes up chromosomes - cell structures that store genetic information

58
Q

describe the role and structure of DNA

A

DNA is made up of two polymer chains that are held together in a double helix
- each polymer chain can be made from 4 different monomers
- nucleotides

59
Q

What does a
nucleotide monomer
consist of?

A

A phosphate group attached to a sugar molecule
attached to one of four bases