Chemistry Triple 2 Flashcards

1
Q

What colour is lithium in a flame?

A

Crimson

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2
Q

What colour is sodium in a flame?

A

Yellow

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3
Q

What colour is potassium in a flame?

A

Lilac

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4
Q

What colour is calcium in a flame?

A

Red

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5
Q

What colour is barium in a flame?

A

Green

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6
Q

How do you test for positive ions?

A

Flame test

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7
Q

How do you do the test for positive ions in a lab?

A

Dip clean wire loop into a sample of the compound and put in a bunsen flame
- loop should be really clean do this by dipping it in hydrochloric acid and rinsing it with distilled water

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8
Q

How do you find what metal is mixed with a metal hydroxide?

A

Add NaOH

Add a few drops of sodium hydroxide solution this would form and insoluble hydroxide and give you a coloured compound

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9
Q

What colour compound does calcium form?

A

White

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10
Q

What colour compound does copper form?

A

Blue

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11
Q

What colour compound does iron2+ form?

A

Green

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12
Q

What colour compound does iron 3+ form?

A

Brown

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13
Q

What colour compound does aluminium form?

A

White at first but the dissolves in excess NaOH to form a colourless solution

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14
Q

What colour compound does magnesium form?

A

White

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15
Q

How do you test for carbonates? ( negative ions)

A

Test for carbon dioxide as carbonate ions react with dilute acids to form carbon dioxide
- acid + carbonate = salt + water + carbon dioxide

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16
Q

How do you test for a halide? ( negative ions)

A

When you add silver ( AgNO3)
A precipitate should form
- chloride gives a white precipitate of silver chloride AgCl
- bromide gives a cream precipitate of silver bromide AgBr
- iodide gives a yellow precipitate of silver iodide AgI

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17
Q

How do you test for sulfate ions?

A

Add dilute HCL followed by barium chloride solution

  • white precipitate of barium sulfate means the original compound was a sulfate
  • Ba2+ + SO42- = BaSO4
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18
Q

What is a reversible reaction?

A

A reversible reaction is one where the products from the reaction can themselves react to produce the original reactants

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19
Q

What is a closed system?

A

None of the reactants or products can escape

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20
Q

What is an equilibrium?

A

Means that the amount if reactants and products will reach a certain balance and stay there

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21
Q

How do you change the position of the equilibrium?

A

Change temperature and pressure

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22
Q

Temperature?

A
  • Increase the temperature, the endothermic reaction will increase to use up the extra heat
  • decrease the temperature, the exothermic reaction will increase to give out more heat
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23
Q

Pressure?

A
  • Increase pressure and it will encourage the reaction which produces less volume ( least molecules)
  • decrease pressure it will encourage the reaction which produces more volume ( most molecules )
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24
Q

What does a catalyst do in a reaction?

A
  • does not change the equilibrium
  • speeds up the forward reaction and backward reaction by the same amount
  • reaches equilibrium quicker
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25
Q

What is the haber process?

A
  1. Hydrogen and nitrogen are mixed
  2. Forward reaction is exothermic so low temperatures 450 degrees and high pressure so it favours side which has least molecules 3. Passed over iron catalyst so it reaches equilibrium quicker
  3. Cooled in condenser and liquid ammonia formed
  4. Waste nitrogen and hydrogen which doesn’t condense is recycled and used again
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26
Q

What is the compromise for pressure?

A
  • high pressure 200 atm and high pressures it favours forward direction so more ammonia will be made and to get the highest % yield
  • 200 atm as the higher the pressure the more expensive the equipment
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27
Q

What is the compromise for temperature?

A

The forward reaction is exothermic so it prefers low temperatures 450 degrees as if temperature is low there will be a slow rate of reaction

28
Q

What is a homologous series?

A

Is a group of chemicals that react in a similar way because they have the same functional group

29
Q

What is a functional group?

A

An atom or group of atoms that give organic compounds their characteristic reactions

30
Q

What are the properties of the first three alcohols?

A
  • flammable and produce carbon dioxide and water by burning in air
  • reacts with sodium to give hydrogen and alkoxides
  • ethanol is the main alcohol in drinks
  • methanol causes blindness when drunk
  • oxidation - ethanol is made in to ethanoic acid by microbes or chemical oxidising agents
  • ethanoic acid is vinegar
31
Q

What are the uses of alcohol?

A
  • solvents - can dissolve substances that water cannot such as oil and fats
  • perfume - ethanol is mixed with oil and water
  • methylated spirit - ethanol with chemical and methanol added to it
32
Q

What is methylated spirit used for?

A

Clean paint brushes and fuel

33
Q

What are the disadvantages of methylated spirit?

A

Poisonous to drink- a purply die is added to it

34
Q

What alcohol can be used as a fuel?

A

Ethanol

- it burns cleanly and it doesn’t smell

35
Q

What are the advantages of alcohol being used at a fuel?

A
  • can be mixed with petrol so it burns more cleanly so less pollution
  • some countries have little oil but lots of sunshine so they grow lots of sugar cane which is renewable
36
Q

What is the functional group of carboxylic acid?

A
  • COOH

- there names end in anoic

37
Q

How does carboxylic acid react with carbonates m?

A

They produce a salt water and carbon dioxide

38
Q

What is the titration calculation?

A

C2= C1V2/V2

C1=C2V2/V1

39
Q

Why do carboxylic acids produce and acidic solution when they dissolve in water?

A

When they dissolve they ionise and release H+ ions this makes the solution acidic
- they don’t ionise completely so only a weak acid is formed, this means they have a higher pH than other solutions of the same concentration which form stronger acids

40
Q

What do you make when you oxidise ethanol?

A

ethanoic acid and water

41
Q

What is ethanoic acid used for?

A

It can be dissolved in water to make vinegar which is used for flavouring and preserving food

42
Q

Are carboxylic acids good for making soaps and esters?

A

Yes, carboxylic acids with long chains if carbon atoms are used to make soaps and detergents. Although they are s good solvent for many organic molecules they are not often chosen as they are too acidic

43
Q

What is the functional group of esters?

A
  • coo
44
Q

What is an ester formed from?

A

An alcohol and a carboxylic acid

Alcohol + carboxylic acid = ester + water

45
Q

What are the properties of an ester?

A
  • smells nice and volatile so they are good for perfumes
  • flammable
  • don’t mix well with water as they are not very soluble
  • do mix with alcohol and other organic solvents
46
Q

What are esters used for?

A

Perfumes
Flavourings and aromas
Ointments
Solvents

47
Q

What are the advantages and disadvantages of of esters?

A
  • inhaling fumes from some esters irritates mucus membranes in the nose and mouth
  • ester fumes are heavier than air and very flammable
  • toxic in large doses
    + aren’t as volatile or as toxic as other organic solvents
48
Q

What is exothermic?

A

Gives out energy to the surroundings - usually heat this is shown when the temperature rises

49
Q

What is endothermic?

A

Takes in energy from the surroundings usually in the form of heat this is shown by a fall in temperature

50
Q

Is a bond breaking exothermic or endothermic?

A

Endothermic

51
Q

Is a bond forming exothermic or endothermic

A

Exothermic

52
Q

How do you measure the energy difference?

A

Take temperatures of the two reagents and mix them in a polystyrene cup then measure the temperature of the solution at the end of the reaction
- amount of energy lost to the surroundings is the biggest problem
So you can reduce this by putting the polystyrene cup into a beaker of cotton wool to give more insulation and put a lid on it to reduce the energy loss by evaporation

53
Q

In an endothermic reaction the energy required to break old bonds is …..

A

Greater than the energy released when new bonds are formed

54
Q

In an exothermic reaction the energy released in bind forming is ….

A

Greater than the energy use in breaking old bonds

55
Q

What is a calorimeter?

A

It can be used to compare the energy released by different fuels or different foods

56
Q

How do you measure the energy transferred?

A

Energy transferred in (j)= mass of water (g) x 4.2 x temperature change

57
Q

What are fuel consequences?

A
  • effects the environment
  • releases carbon dioxide which is a green house gas which causes global warming
  • expensive to slow down the affects of climate change
  • crude oil is running out so it will get more expensive and have a bigger economic impact
58
Q

What does a catalyst do?

A

Lowers the activation energy

59
Q

What is the activation energy?

A

The minimum energy needed to start off a reaction

60
Q

What happens when you lower the activation energy?

A

The reaction happens more quickly and easily although the energy change for the reaction remains the same

61
Q

What are the benefits and disadvantages of hydrogen?

A

+ very clean

  • very explosive so you have to store it carefully
  • special expensive engine
62
Q

What is a fuel cell?

A

An electrical cell that is supplied with a fuel and oxygen and uses energy from the reaction between them to generate electricity

63
Q

What are the benefits and disadvantages of a fuel cell?

A

+ doesn’t run out
+ doesn’t need charging
+ safer than nuclear
+ more practical than solar cells

64
Q

How do you get energy from hydrogen and oxygen?

A

They produce water when they react
Its an exothermic reaction so they produce energy
You would get the energy by reacting hydrogen and oxygen in a combustible engine or a fuel cell

65
Q

What effect has a fuel cell had on the car industry?

A

+ no greenhouse gases, nitrogen oxides, sulfur dioxide or carbon monoxide
- hydrogen has to be made from hydrocarbons from fossil fuels or electrolysis of water which uses energy

66
Q

What is a fuel cell?

A

An electrical cell that is supplied with a fuel and oxygen and uses energy from the reaction to generate electricity