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Z/ HIGHER Chemistry > Unit 2: Chapter 6 - Oils and Fats > Flashcards

Unit 2: Chapter 6 - Oils and Fats Flashcards

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1
Q

From what origins can oils and fats be of?

A

Animal,vegetable or marine origin.

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2
Q

How are vegetable oils usually produced?

A

By ‘pressing’ oil out of the plant seed.

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3
Q

How are animal fats usually produced?

A

By ‘rendering down’ a process which separates the fats from the bone and protein of the fatty parts of the animal.

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4
Q

How are marine oils usually produced?

A

By ‘boiling’ the blubber from whales, and the liver from the cod fish, which separates the oil from the tissue which floats on the surface.

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5
Q

What is the difference between fats and oils?

A

The ‘degree of saturation’

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6
Q

In fats what are the hydrocarbon chains like and what does this mean for the compound?

A

In fats the hydrocarbon chains are ‘saturated’. this allows the molecules to pack neatly together meaning the LONDON DISPERSION FORCES ARE STRONG. Due to this the compound is SOLID.

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7
Q

In oils what are the hydrocarbon chains like and what does this mean for the compound?

A

In oils the hydrocarbon chains are ‘unsaturated’, the double bond creates a bend i the hydrocarbon chains pushing the molecules apart meaning the LONDON DISPERSION FORCES ARE WEAKER. Due to this the compound is LIQUID.

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8
Q

What are oils and fats both in water and what does this mean they can be called?

A

Oils and fats are insoluble in water and can be called ‘hydrophobic’.

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9
Q

What does ‘hydrophobic’ mean?

A

Water hater.

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10
Q

If molecules contain an OH group are they always soluble in water?

A

No it depends the size of the rest of the molecule that is insoluble. i.e. if a molecule has 1 OH and the rest is covalent bonds, then most of the molecule is insoluble so no it is not soluble in water. However if the molecule contains a few OH groups with not as much of the molecule being insoluble in water then the molecule will be soluble in water and can be called hydrophillic.

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11
Q

What does hydrophillic mean?

A

Water lover.

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12
Q

What is turning an oil into a fat commonly known as?

A

Hardening

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13
Q

What does the process of hardening usually involve?

A

Passing hydrogen, which is under pressure, through a hot oil.

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14
Q

What is the process of adding hydrogen called?

A

Hydrogenation

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15
Q

What does hydrogenation do in the process of turning oils into fats?

A

It encourages an addition reaction where the hydrogen adds on to the c=c in the fatty acid chain. Hence decreasing the unsaturation of the oil, increasing the melting point and creating a fat.

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16
Q

What is an example of turning an oil into a fat?

A

Sunflower oil + Hydrogen = Sunflower margarine.

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17
Q

What do fats and oils consumed in our diet provide us with?

A

The fats and oils consumed in our diet provide the body with a concentrated source of energy(even more than carbohydrates) and are essential for the transport and storage of fat-soluble vitamins in the body .

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18
Q

What is a disadvantage to fats and oils in our diet?

A

The are a major source of heart disease and coronary problems.

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19
Q

What are fats and oils in terms of esters?

A

Edible fats and edible oils are esters formed from the condensation of glycerol (propane 1,2,3-triol) and three carboxylic acid molecules.

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20
Q

What are the variety of carboxylic acids also called in fats and oils?

A

Fatty acids.

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21
Q

What do the fatty acids in fats and oils contain?

A

Fatty acids contain only one carboxyl group attached to a long hydrocarbon (alkyl) chain.
or
fatty acids and can be saturated or unsaturated straight-chain carboxylic acids, usually with
long chains of carbon atoms.

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22
Q

In fats and oils what is the only alcohol called?

A

Glycerol

23
Q

What is the structure of glycerol like?

A

Glycerol is a complex alcohol as it has three -OH group and is a triol.

24
Q

Do edible oils have lower melting points than edible fats?

A

YES

25
Q

What does the double bond in fatty acids prevent happening in oils and what does this mean for the properties of oils?

A

Double bonds in fatty acid chains prevent oil molecules from packing closely together, so the greater the number of double bonds present, the weaker the van der Waals forces of attraction. The greater the degree of unsaturation, the lower the melting point.

26
Q

When a fat or oil forms through a condensation reaction, each glycerol molecule can form what with what molecules?

A

An ester link with three fatty acid molecules.

27
Q

As all fats and oils contain the ester link what can they be classified as?

A

Esters

28
Q

What do we use to break down a fat or oil?

A

The hydrolysis(alkaline) reaction with superheated steam.

29
Q

What will hydrolysis break a fat or oil down into?

A

The fatty acids and glycerol.

30
Q

When the hydrolysis reaction of fats and oils is complete what are we always left with?

A

1 mole of glycerol and 3 moles of fatty acid.

31
Q

What chains do both fats oils contain?

A

Saturated and unsaturated alkyl chains.

32
Q

What is the test for oils/unsaturated compounds?

A

Bromine water.

33
Q

What is the difference between fats and oils decolourising bromine water?

A

The more unsaturated oil will continue to decolourise bromine water long after the fat has stopped decolourising the bromine water so the bromine water will be more decolourise by the oil than the fat.

34
Q

Why do oils have lower melting points and have a higher degree of unsaturation?

A

They have more c=c bonds.

35
Q

How does the bromine water work in oils and fats and why can you tell the difference between the two?

A

The bromine molecules add across the carbon–carbon double bonds in an addition reaction.

36
Q

What do more double bond like that of an oil compared to a fat do to bromine water?

A

The greater the number of double bonds present in a substance, the more bromine solution can be decolourised.

37
Q

What are soaps produced from?

A

The alkaline hydrolysis of oils and fats you sodium or potassium hydroxide.

38
Q

What does normal hydrolysis of oils and fats with superheated steam produce?

A

One Glycerol molecule and three fatty acid molecules.

39
Q

What does hydrolysis of oils and fats by the use of a strong alkali produce?

A

Glycerol and 3 fatty acid molecules which are neutralised by the alkali, forming water soluble, ionic salts called soaps.

40
Q

What another name for glycerol?

A

Propan - 1,2,3 - triol.

41
Q

What are soaps produced from?

A

Soaps are made from the alkaline hydrolysis of oils and fats like sodium or potassium hydroxide.

42
Q

What are the fatty acids neutralised by in the hydrolysis of fats and oils and what does this produce?

A

By the alkali, forming water soluble, ionic salts called soaps.

43
Q

What are the ionic salts produced when the alkaline neutralises the fatty acids in the alkaline hydrolysis of oils and fats also called?

A

Soaps

44
Q

Why is the soap molecule useful for cleaning?

A

Soap ions have long non-polar tails, readily soluble in non-polar compounds (hydrophobic), and ionic heads that are water-soluble (hydrophilic). The hydrophobic tails dissolve in the oil or grease. The negatively-charged hydrophilic heads remain in the surrounding water.

45
Q

How do soaps work to clean things?

A

The hydrophobic tails dissolve in the oil or grease. The negatively-charged hydrophilic heads remain in the surrounding water.Agitation causes ball-like structures to form. The negatively-charged ball-like structures repel each other and the oil or grease is kept suspended in the water.

46
Q

What is hard water and when does this occur?

A

Hard water is a term used to describe water containing high levels of dissolved metal ions. When soap is used in hard water, scum, an insoluble precipitate, is formed.

47
Q

What are soap less detergents?

A

Soapless detergents are substances with non-polar hydrophobic tails and ionic hydrophilic heads

48
Q

What do soap less detergents do?

A

They remove oil and grease in the same way as soap. Soapless detergents do not form scum with hard water.

49
Q

What is an emulsion?

A

An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable).

50
Q

What is an emulsifier Do?

A

An emulsifier can be used to prevent non-polar and polar liquids separating into layers.

51
Q

What is an example of an emulsifier being used?

A

When soap or detergent is applied to a mixture of oil and water.

Fats and water in milk and mayonnaise.

52
Q

What does an emulsifier contain?

A

An emulsion contains small droplets of one liquid dispersed in another liquid.

53
Q

What is the emulsifier in milk called?

A

Sodium caesinate.

Z/ HIGHER Chemistry (25 decks)

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