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HCHS GCSE Science 2 - Chemistry > Section 9 - Separate Chemistry 2 > Flashcards

Section 9 - Separate Chemistry 2 Flashcards

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1
Q

What is flame photometry?

A

An instrumental method of analysis for identifying ions in a dilute solution.

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2
Q

How does flame photometry work?

A

Each ion produces a unique line spectrum, the intensity of the wavelength indicates the concentration of that ion in solution.

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3
Q

How can ion concentration in solution be calculated from emission intensity in flame photometry?

A

By using a calibration curve, find emission intensity on the y-axis and draw a horizontal line until you reach the curve, then draw straight down to reach the concentration.

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4
Q

What are instrumental analysis methods?

A

Tests that use machines, removing the need for humans.

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5
Q

What are the benefits of using instrumental methods of analysis?

A

Very sensitive, which allows tests for tiny amounts of substances.
Very fast, tests can even be automated.
Very accurate, removes human error, unlike manual analysis.

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6
Q

What are hydrocarbons?

A

Molecules containing only hydrogen and carbon.

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7
Q

What are alkanes?

A

A homologous series of saturated hydrocarbons.

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8
Q

What is a homologous series?

A

A group of compounds with similar chemical properties, chemical structure and general formula.

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9
Q

What is the general formula of alkanes?

A

CₙH₂ₙ₊₂

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10
Q

What does it mean if a compound is saturated?

A

The atoms in the compound have formed bonds with as many other atoms as they can, meaning there are no double or triple bonds.

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11
Q

What are alkenes?

A

A homologous series of unsaturated hydrocarbons which all have one double bond between two carbon atoms, known as a C=C functional group.

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12
Q

What is the general formula of alkenes?

A

CₙH₂ₙ

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13
Q

What does it mean if a compound is unsaturated?

A

The compound contains at least one double or triple bond so more bonds could be formed if the double or triple bonds were opened.

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14
Q

How can alkenes be tested for? Why does this happen?

A

When alkenes are shaken together with bromine water, the bromine water will decolourise, turning from orange to colourless. This happens because an addition reaction occurs where the bromine is added across the double bond.

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15
Q

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

A

ethane+oxygen→carbon dioxide+water

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16
Q

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

A

ethene+oxygen→carbon dioxide+water

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17
Q

What is the symbol equation for the complete combustion of ethane?

A

2C₂H₆+7O₂→4CO₂+6H₂O

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18
Q

What is the symbol equation for the complete combustion of ethene?

A

C₂H₄+3O₂→2CO₂+2H₂O

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19
Q

What are polymers?

A

A substance made up primarily or completely of smaller units called monomers.

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20
Q

What are addition polymers?

A

Polymers made from unsaturated monomers.

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21
Q

How do addition polymers form?

A

In addition polymerisation, the double bonds in unsaturated monomers are opened allowing the units to join up to form a longer addition polymer chain.

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22
Q

How are addition polymers named?

A

Put brackets around the name of the monomer it’s made from and put the word poly around it. (E.G; poly(ethene), also known as polythene)

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23
Q

What are monomers?

A

Molecules that can bond with other identical molecules (or a few other types of monomer in a repeating pattern) to form a polymer.

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24
Q

What are condensation polymers?

A

Polymers made of multiple types of monomer, each type having at least two functional groups, one at either end of the molecule.

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25
Q

How do condensation polymers form?

A

In condensation polymerisation, each functional group reacts with the functional group of another monomer, creating chains of alternating monomers. Each new bond formed releases a small molecule.

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26
Q

What are polyesters?

A

Polyesters are condensation polymers formed when dicarboxylic acid monomers react with diol monomers.

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27
Q

What are dicarboxylic acid monomers?

A

Monomers that contain two carboxylic acid (-COOH) groups.

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28
Q

What are diol monomers?

A

Monomers containing two alcohol (-OH) groups.

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29
Q

What is the bond formed when a carboxylic acid group reacts with an alcohol group called?

A

An ester link.

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30
Q

What molecule is lost when an ester link forms?

A

One water molecule.

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31
Q

What are three examples of natural polymers?

A

DNA, proteins and large carbohydrates.

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32
Q

What monomers form DNA?

A

The four different nucleotide monomers.

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33
Q

What monomers form proteins?

A

Amino acids.

34
Q

What are carbohydrates?

A

Molecules containing carbon, oxygen and hydrogen.

35
Q

What are two examples of large carbohydrates?

A

Starch and cellulose.

36
Q

What monomers form large carbohydrates?

A

Smaller units of carbohydrates called sugars.

37
Q

What are plastics?

A

A type of polymer which are made from crude oil.

38
Q

What type of resource is crude oil?

A

Finite and natural.

39
Q

What does it mean for something to be finite?

A

There is a limited amount of it.

40
Q

What does it mean for something to be renewable?

A

More can always be produced.

41
Q

What will happen to the price of crude oil and crude oil products as we use more of them?

A

The price increases because there is a limited supply of crude oil.

42
Q

What are some of the common uses of crude oil?

A

Plastics, heating, fuel and building.

43
Q

How can we delay the problem of running out of oil?

A

Recycling our polymers, so less need to be produced.

44
Q

How much plastic waste is produced by the UK every year on average?

A

2 million tonnes.

45
Q

What are the three main ways of disposing of plastics?

A

Landfill, combustion and recycling.

46
Q

Why do we dispose of plastics in landfills?

A

We usually use landfills when different polymers are too difficult or expensive to separate and recycle.

47
Q

What are the advantages of using landfill sites to dispose of plastics?

A

It is simpler and easier to dispose of plastics by sticking them in a hole in the ground and forget about them.

48
Q

What are the disadvantages of using landfill sites to dispose of plastics?

A

A lot of valuable land is wasted as landfill.

Most plastics are non-biodegradable and are not broken down, meaning that they will stay in the landfill for many years.

49
Q

What are the advantages of using combustion to dispose of plastics?

A

Burning plastics produces a lot of energy, which can be used to generate electricity.

50
Q

What are the disadvantages of using combustion to dispose of plastics?

A

If not carefully controlled, toxic gasses can be released from the combustion of plastics, which must be removed.
Carbon dioxide is also released which leads to global warming.

51
Q

What are the advantages of recycling plastics?

A

Reduces the amount of non-biodegradable waste filling up landfill sites.
Reduces the emissions of greenhouse and toxic gases which can be released from burning plastics.
Recycling uses less water and energy than making new plastics.
Reduces the amount of crude oil that is used to produce more plastics.
Saves money and creates jobs.

52
Q

What are the disadvantages of recycling plastics?

A

Polymers must be separated by type before they can be melted and reformed into new products, this can be difficult and expensive.
If polymers are mixed together in recycling the quality of the recycled plastic could be reduced.
Polymers can only be recycled a finite number of times, over time the strength of the plastic can decrease.
Melting polymers can release harmful gasses into the atmosphere which may affect plants and animals.

53
Q

What are alcohols?

A

A homologous series containing at least one -OH functional group.

54
Q

What is the general formula of an alcohol?

A

CₙH₂ₙ₊₁OH

55
Q

What are the two meanings of oxidised?

A

When something oxidises, it either gains oxygen or has lost an electron in a chemical reaction.

56
Q

What happens when alcohols are oxidised?

A

They form carboxylic acids.

57
Q

What is needed for an alcohol to be oxidised?

A

There must be an oxidising agent and the -OH functional group must be attached to a carbon atom that is only attached to one other carbon atom.

58
Q

How are alcohols named?

A

They share the basic naming system of alkanes, but the final e is replaced with “-ol”.

59
Q

How are carboxylic acids named

A

They share the basic naming system of alkanes, but the final e is replaced with “-oic acid”

60
Q

What are carboxylic acids?

A

A homologous series containing at least one -COOH functional group.

61
Q

What is the general formula of carboxylic acids?

A

Cₙ₋₁H₂ₙ₋₁COOH

62
Q

Why do members of a homologous series have similar reactions?

A

They contain the same functional group.

63
Q

How is ethanol produced?

A

Through fermentation.

64
Q

What is fermentation?

A

The process of using yeast to convert a type of carbohydrate called sugars into alcohol.

65
Q

What is the word equation for the fermentation to produce ethanol?

A

glucose→ethanol+carbon dioxide

using yeast

66
Q

What is the symbol formula for the fermentation to produce ethanol?

A

C₆H₁₂O₆→2C₂H₅OH+2CO₂

using yeast

67
Q

What are common sources of carbohydrate for commercial alcohol production

A

Sugar cane and sugar beet plants.

68
Q

What is yeast?

A

A single-celled fungus.

69
Q

Why is yeast used in fermentation?

A

The yeast cells contain an enzyme that converts sugar into alcohol.

70
Q

What is the best temperature for fermentation? Why must the temperature be controlled?

A

Between 30°C and 40°C. If it gets too cold, the reaction will slow down, if it gets too hot, the enzyme in the yeast will denature and the reaction will stop.

71
Q

Describe how a solution of ethanol could be made by fermentation.

A

Yeast and a solution of carbohydrate would be mixed into a clean container before sealing the container and leaving it in a warm place.
When the concentration of ethanol reaches 10 to 20% the fermentation stops because the yeast gets killed off by the alcohol.
The dead yeast falls to the bottom of the container and the ethanol solution can be collected from the top.

72
Q

How can the concentration of an alcohol be increased?

A

Through fractional distillation.

73
Q

Describe the process of distilling ethanol.

A

A dilute solution of ethanol is heated, ethanol has a lower boiling point than water so it evaporates quicker.
The ethanol vapour raises through a fractionating column leaving the water behind.
A Liebig condenser cools the ethanol vapour, causing it to condense.
The concentrated ethanol can be collected in a separate flask.

74
Q

What is a Liebig condenser? How does it work?

A

A long tube inside another tube, vapour passes through the inner tube and cold water passes through the outer tube. The vapour is cooled and condenses into a liquid which then leaves the condenser.

75
Q

Why should fermentation be done in a sealed container?

A

This keeps the reaction anaerobic, without oxygen, if oxygen was present it would produce carboxylic acids, like ethanoic acid, which is found in vinegar.

76
Q

What is the correlation between the carbon chain length of an alcohol and the efficiency of the alcohol as a fuel?

A

The longer the carbon chain, the higher the fuel efficiency of the alcohol.

77
Q

What are nanoparticles?

A

Particles 1-100 nanometers across, larger than atoms and simple molecules but smaller than most other things.

78
Q

What makes nanoparticles important?

A

They have very different properties to the bulk chemical that it’s made from.

79
Q

What is the equation for surface area to volume ratio?

A

Surface area to volume ratio=surface area×volume

80
Q

Describe how a particles size affects its surface area to volume ratio.

A

As particles decrease in size, the size of their surface area increases in relation to their volume, so their surface area to volume ratio increases.

81
Q

Describe how nanoparticles’ surface area to volume ratio affects their properties.

A

Nanoparticles have really high surface area to volume ratios compared to larger particles, this means a much greater proportion of their atoms are able to interact with substances they come into contact with, which affects how they react with other substances.

82
Q

What are some uses of nanoparticles and some examples of them?

A

Their huge surface area to volume ratio makes them good catalysts due to the higher number of possible collisions with the catalyst’s surface.
New cosmetics, such as sunscreens which provide better protection without leaving white marks on the skin.
Nanomedicine is testing using fullerenes, which are more easily absorbed into the body than most particles as a way to deliver medication right into the necessary cells.
Lubricants in artificial joints and gears.
Nanotubes are highly conductive and could be used in tiny electrical circuits for computer chips.
They strengthen sports equipment such as tennis rackets, golf clubs and balls.
Silver nanoparticles added to polymer fibres gives surgical masks, gloves and wound dressings antibacterial protection.

HCHS GCSE Science 2 - Chemistry (9 decks)

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