Unit 2 Flashcards

1
Q

What is the definition of alkanals?

A

A homologous series of aldehydes

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2
Q

What is the general formula for alkanals?

A

C (n) H(2n) O

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3
Q

What is the definition of alkanes?

A

A homologous series of saturated hydrocarbons eg methane

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4
Q

What is the general formula for alkanes?

A

C (n) H (2n + 2)

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5
Q

What is the definition of alkanoic acids?

A

A homologous series of carboxylic acids

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6
Q

What is the general formula for alkanoic acids?

A

C (n) H (2n) O (2)

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7
Q

What is the definition of alkanols?

A

A homologous series of alcohols

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8
Q

What is the general formula for alkanols?

A

C (n) H (2n + 1) OH

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9
Q

What is the definition of alkanones?

A

A homologous series of ketones

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10
Q

What is the general formula for alkanones?

A

C (n) H (2n) O eg. propanone

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11
Q

What is the definition of alkanes?

A

A homologous series of unsaturated hydrocarbons. Each member contains a carbon-carbon double bond

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12
Q

What is the definition of an alkyl group?

A

A group of carbon and hydrogen atoms forming a branch in a carbon compound

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13
Q

What is the definition of an amide link?

A

Group of atoms formed by the condensation polymerisation of amino acids in the formation of protein chains. The amide link is -CO-NH- and occurs between each pair of amino acid residues in the chain.

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14
Q

What is the definition of amino acids?

A

Compounds of general formula, H2NCHRCOOH, which link by condensation reaction to form proteins.

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15
Q

What is the definition of an antioxidant?

A

Compounds that slow oxidation reactions

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16
Q

What is the definition of a carbonyl group?

A

The functional group present in ketones, C=O

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17
Q

What is the definition of carboxylic acids?

A

The functional group present in carboxylic acids, -COOH.

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18
Q

Where does name for a carboxylic group derive from?

A

The name derives from the fact that the carboxyl group contain a carbonyl and hydroxyl group

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19
Q

What is the definition of emulsion?

A

A mixture of liquids where small droplets of one liquid are dispersed into another liquid.

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20
Q

What is the definition of essential amino acids?

A

Amino acids that cannot be made by the body and need to be obtained through diet.

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21
Q

What is the definition of fatty acids?

A

Carboxylic acids formed from the hydrolysis of days and oils

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22
Q

What is the definition of glycerol?

A

Propan-1,2,3-triol

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23
Q

How is glycerol formed?

A

From the hydrolysis of fats and oils

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24
Q

What is the definition of hardening?

A

The process of hydrogenating an oil to produce a more solid compound

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25
Q

What is the definition of hydration?

A

The addition of water to an unsaturated compound

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26
Q

What is the definition of hydrogenation?

A

The addition of hydrogen to an unsaturated compound.

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27
Q

What is the definition of hydrolysis?

A

The breaking down of larger molecules into smaller molecules by the reaction of water

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28
Q

What is the definition of hydrophilic?

A

A term used to describe molecules, or parts of a molecule, which are attracted to water.

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29
Q

What is the definition of hydrophobic?

A

A term used to describe molecules, or parts of a molecule, which repeal water and will not bond to water.

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30
Q

What is the definition of miscibility?

A

The ability of liquids to mix perfectly together

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31
Q

What is the definition of oils?

A

Esters formed from one mole of glycerol and three molecules of (usually unsaturated) carboxylic acids.

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32
Q

What is the definition of fats?

A

Esters formed from one molecule of glycerol and three molecules of (usually unsaturated) long-chain carboxylic acids.

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33
Q

What is the definition of oxidation?

A

A process in which electrons are lost

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34
Q

What is the definition of oxidising agent?

A

A substance that gains electrons, in other words is an electron acceptor.

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35
Q

What is the definition of a reducing agent?

A

A substance that loses electrons,in other words is an electron donor

36
Q

What is the definition of a saturated hydrocarbon?

A

A hydrocarbon in which all carbon-carbon covalent bonds are single bonds

37
Q

What is the definition of soaps?

A

Salts of fatty acids, e.g. sodium stearate. Soaps have an ionic head that is water soluble and a covalent tail that is soluble in oil.

38
Q

What is the definition of a triglyceride and how are they formed?

A

The molecules found in fats and oils. They are formed from one glycerol molecule joining to three fatty acid molecules

39
Q

What is the definition of unsaturated compounds?

A

Compounds in which there are carbon-carbon double or triple bonds.

40
Q

What is the definition of alcohols?

A

Carbon compounds which contain the hydroxyl functional group, -OH

41
Q

What is the process of making an ester known as?

A

A condensation reaction

42
Q

What are some uses of esters?

A

Solvents, flavourings or perfumes

43
Q

What happens when oils are tested with bromine water?

A

Shaking of oils with bromine water results in the bromine water being rapidly decolourised, with bromine a decolourisation being the standard test for unsaturation

44
Q

What is the only chemical difference between fats and oils?

A

Oils contain many more double bonds

45
Q

How can hardening of oils be carried out?

A

By the addition of hydrogen across the double bonds

46
Q

Why do fats and oils not dissolve in water?

A

Because they are non-polar. The long hydrocarbon chains cannot bond to water and there are no polar -OH groups or ions that can bond to water

47
Q

How are soaps derived?

A

From fats or oils by treating them with an alkali such as sodium hydroxide or potassium hydroxide. This results in alkaline hydrolysis of the three ester links in the fat or oil, and produces glycerol and the salt of the fatty acids. These salts are ‘soap’

48
Q

Why are fats and oils an essential part of the human diet?

A

Fats and oils are used in our diets to provide us with energy. They play an important role in the transport of vitamins which are soluble in fats around the human body.

49
Q

What do precipitates do?

A

The precipitates reduce the cleansing action of soap and build up to leave a ‘scum’ around baths etc

50
Q

How are aldehydes formed?

A

They are formed by oxidation of primary alcohols

51
Q

What functional group do aldehydes contain?

A

-CHO functional group

52
Q

What do aldehydes oxidise to produce?

A

Carboxylic acids

53
Q

What when oxidised produces an aldehyde?

A

A primary alcohol

54
Q

What when oxidised produces a ketone?

A

A secondary alcohol

55
Q

What do tertiary alcohols oxidise to produce?

A

They are not readily oxidised

56
Q

How can aldehydes and ketones be identified?

A

The presence of a carbon-oxygen double bond, C=O, which is known as the carbonyl group

57
Q

Which can be readily oxidised, aldehydes or ketones?

A

Aldehydes

58
Q

What are 3 common oxidising agents used to determine aldehydes from ketones?

A

Acidified potassium dichromate solution, Fehling’s solution or Tollens’ reagent

59
Q

What is the definition of an aldehyde, how are they formed and what do they produce when oxidised?

A

Carbon compound which contain the -CHO functional group. They are formed by oxidation of primary alcohols and the oxidise to produce carboxylic acids.

60
Q

What is an antioxidant?

A

Compounds that slow oxidation reactions.

61
Q

Give an example of an antioxidant

A

Vitamin C, vitamin E etc.

62
Q

What is a carbonyl group?

A

The functional group present in ketones, C=O. Also present in aldehydes as part of their functional group, -CHO, and in carboxylic acids as part of their functional group, -COOH.

63
Q

What is the definition of denaturing of proteins?

A

Altering the shape of a protein by an increase in temperature or a reduction in pH

64
Q

What is a consequence of denaturing of proteins?

A

Loss of enzyme activity

65
Q

What are ketones?

A

Carbon compounds that contain the carbonyl group (C=O).

66
Q

How are ketones formed?

A

From the oxidation of secondary alcohols

67
Q

Ketones can be oxidised using mild oxidising agents such as acidified potassium dichromate solution. True or false?

A

False

68
Q

What are essential oils?

A

Oils extracted from plants.

69
Q

What are characteristics of essential oils?

A

They usually have distinctive smells, are non-polar, and often contain compounds known as terpenes.

70
Q

What is the definition of free radical?

A

Highly reactive atoms or molecules with unpaired electrons

71
Q

What is the definition of free radical scavenger?

A

A compound added to plastics, cosmetics and foods to prevent free radical reactions. They react with free radicals to produce stable molecules which terminates the reaction.

72
Q

What is the definition of a terpene?

A

Unsaturated compounds found in many plant oils.

73
Q

How are terpenes formed?

A

They are formed from the joining of isoprene units.

74
Q

What are the three steps of a free radical reaction?

A

Initiation, propagation and termination

75
Q

What happens in the initiation step of a free radical reaction?

A

U.V. light provides the energy for the homolytic fission of halogen into reactive halogen atoms or free radicals (atoms with an unpaired electron).

76
Q

What happens in the propagation step of a free radical reaction?

A

In this stage, free radicals collide with other species but the number of free radicals is maintained (hence the term propagation).These reactions continue until reactants are used up, or until free radicals are used up by collision with each other.

77
Q

What happens in the termination step of a free radical reaction?

A

In this stage, free radicals are used up by collision with each other.

78
Q

What does sun screen do?

A

Sun screens contain compounds that filter the UV light so that less UV reaches the skin

79
Q

What does sun block do?

A

Sun block contains compounds such as titanium dioxide that reflect the UV so that it does not reach the skin at all

80
Q

Many flavour and aroma molecules come from which family?

A

Aldehydes

81
Q

What happens to proteins during cooking?

A

The intermolecular bonds are broken allowing theproteins to change shape (denature). Thesechanges alter the texture of foods.

82
Q

What is the meaning of denature?

A

A permanent chemical change to the physical shapeof a protein/enzyme. This can happen at hightemperatures.

83
Q

What are essential oils?

A

Essential oils are concentrated extracts of the volatile,non-water soluble (hydrophobic) aroma compounds fromplants. The oils have the aroma of the plant from whichthey are extracted.

84
Q

How are essential oils extracted from plants?

A

Steam distillation

85
Q

What can happen when skin is exposed to uv rays?

A

Exposure to UV light can result in molecules gaining sufficient energy for bonds to be broken. This is the process responsible for sunburn and also contributes to aging of the skin

86
Q

What is the meaning of unsaturated?

A

Compounds which have double (or triple) covalent bonds between carbon atoms e.g. alkenes such as ethane.

87
Q

What is substitution?

A

A reaction where one atom is replaced by another atom.