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chemistry gcse > Chemical Analysis > Flashcards

Chemical Analysis Flashcards

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1
Q

What does pure mean?

A

A substance that only contains one type of element or compound

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2
Q

Pure substances do what over a range of temperatures?

A

Change state

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3
Q

What is the name of the one temperature that pure substances melt and solidify at?

A

Melting point

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4
Q

What is the name of the one temperature that pure substances boil and condense at?

A

Boiling point

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5
Q

What is a formulation?

A

Mixtures that have been designed to have specific properties

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6
Q

What happens during chromatography?

A

Mixtures separate into their components

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7
Q

Why do the components separate during chromatography?

A

They move a different distance depending on its attraction for the paper and solvent

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8
Q

What can chromatography be used for?

A

To identify artificial colours (in food) by comparing it with results from known substances

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9
Q

Equation for Rf value

A

Distance moved by substance/distance moved by solvent

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10
Q

What is the Rf value used for in chromatography?

A

To identify the component

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11
Q

What are the properties of hydrogen?

A

Colourless, combines violently with oxygen when ignighted

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12
Q

What is the test for hydrogen?

A

Lit splint and burns with squeaky pop

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13
Q

What are the properties of chlorine?

A

A green, poisonous gas that bleaches dyes

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14
Q

What is the test for chlorine?

A

Turns damp red litmus paper white

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15
Q

What are the properties of oxygen?

A

A colourless gas that helps fuels burn more readily than in air

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16
Q

What is the test for oxygen?

A

Relights a glowing splint

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17
Q

What are the properties of carbon dioxide?

A

Colourless gas

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18
Q

What is the test for carbon dioxide?

A

Turns limewater cloudy when bubbled through it

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19
Q

What are instrumental methods?

A

Standard lab equipment is used to detect and identify substances

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20
Q

What is flame emission spectroscopy used for?

A

To identify metal ions in a substance which contains more than 1 ion

21
Q

How does emission spectroscopy work?

A

The metal solution is placed in a flame and the light emitted is passed through a spectroscope

22
Q

What can the line spectrum produced by a substance in emission spectroscopy be used for?

A

Identifying ions, measuring the concentration of the metal ions

23
Q

What are flame tests used for?

A

To identify a metal ion in a substance that contains only 1 ion

24
Q

What colour does copper go in a flame test?

A

Green

25
Q

What colour does calcium go in a flame test?

A

Brick red

26
Q

What colour does lithium go in a flame test?

A

Crimson red

27
Q

What colour does potassium go in a flame test?

A

Lilac

28
Q

What colour does sodium go in a flame test?

A

Yellow

29
Q

What problem occur in flame test if a sample contains more than 1 metal ion?

A

It can be hard to detect them all as they can mask each other

30
Q

Carbonates react with dilute acids to form what?

A

Carbon dioxide + salt + water

31
Q

Most metal carbonates are insoluble, but which 2 aren’t?

A

Potassium carbonate

Sodium carbonate

32
Q

What is a precipitate?

A

An insoluble solid that came out of a solution

33
Q

What substance do we add to a solution in metal ion precipitate tests?

A

Sodium hydroxide

34
Q

How do we name the precipitate formed in precipitate test?

A

Name of metal ion + hydroxide

35
Q

What colour is the precipitate of aluminium, Al3+?

A

White - dissolves if more sodium hydroxide is added

36
Q

What colour is the precipitate of calcium, Ca2+?

A

White

37
Q

What colour is the precipitate of magnesium, Mg2+?

A

White

38
Q

What colour is the precipitate of copper(II), Cu2+?

A

Blue

39
Q

What colour is the precipitate of iron(II), Fe2+?

A

Green

40
Q

What colour is the precipitate of iron(III), Fe3+?

A

Brown

41
Q

What is the positive result of a sulfate test?

A

A white precipitate of barium sulfate is formed

42
Q

How do we carry out the sulfate test?

A

By adding dilute hydrochloric acid and barium chloride to a solution

43
Q

What are the halide ions?

A

Chlroide, bromide and iodide (ions)

44
Q

What is the test for halides?

A

Adding silver nitrate in the presence of dilute nitric acid forms a silver halide precipitae

45
Q

A chloride gives a …precipitate of silver chloride

A

White

46
Q

A bromide gives a … precipitate of silver bromide

A

Cream

47
Q

An iodide gives a … precipitate of silver iodide

A

Yellow

48
Q

Mobile phase of chromatography

A

Where molecules can move

Always liquid or gas

49
Q

Stationary phase in chromatography

A

Molecules can’t move

Can be solid or really thick liquid

chemistry gcse (10 decks)

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