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Chemistry - Unit Three > Further Analysis and Quantative Chemistry > Flashcards

Further Analysis and Quantative Chemistry Flashcards

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1
Q

What is a titration?

A

An experiment that lets you see what volume of a reactant is needed to react completely with a certain volume of another reactant.

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2
Q

How do you use titration to work out how much acid is needed to neutralise a set amount of an alkali?

A

1) Use a pipette to measure out a volume of alkali
2) Put the alkali in a flask with some indicator
3) Put the acid in a burette. Run a small amount out and then turn the tap off.
4) Taking a reading of the volume of acid using the bottom of the meniscus.
5) Add the acid to the alkali in 1 cubic centimetre amounts. Swirl the flask each time.
6) When the indicator changes colour the reaction is finished. Record the change in volume of acid used.
7) Repeat the experiment several times and work out a mean amount of acid used.

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3
Q

What is the meniscus?

A

The curve in the surface of the acid in a burette.

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4
Q

Why can’t universal indicator be used during a titration?

A

Because it changes colour gradually rather than has a sudden change.

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5
Q

What are two indicators that are useful for titrations?

A

Phenolphthalein and methyl orange.

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6
Q

What colour is phenolphthalein in an alkali? What colour is it in an acid?

A

It is pink in alkalis but colourless in acids.

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7
Q

What colour is methyl orange in alkalis? What colour is it in acids?

A

It is yellow in alkalis but red in acids.

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8
Q

How do you convert between litres, cubic decimetres and cubic centimetres?

A

1 litre = 1 cubic decimetre = 1000 cubic centimetres

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9
Q

How do you work out concentrations in moles per cubic decimetre?

A

1) Worl out how many moles of the known substance you have using :

Number of moles = concentration (mol/cubic decimetre) x volume (cubic decimetre)

2) Write down the balanced equation of the reaction and work out many moles of the unknown substance you have
3) Work out the Unknown concentration using this formula:

Concentration (mol/cubic decimetre) = number of moles / volume (cubic decimetres)

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10
Q

How do you work out concentrations in grams per cubic decimetre?

A

1) Work out the Mr of the acid
2) Convert to number of moles from the concentration in mol/cubic decimetres using:

Mass (g) = moles x relative formula mass

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11
Q

What is the flame test a test for?

A

Metal ions

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12
Q

How does one conduct a flame test?

A

Put the substance on a wire loop in the blue part of a flame and see what colour the flame goes. The loop should be washed in hydrochloric acid and then distilled water after each test to make sure it is clean.

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13
Q

What colour flame does a lithium L+ ion produce in a flame test?

A

Crimson

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14
Q

What colour flame does a sodium Na+ ion produce in a flame test?

A

Yellow

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15
Q

What colour flame does a potassium K+ ion produce in a flame test?

A

Lilac

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16
Q

What colour flame does a calcium Ca2+ ion produce in a flame test?

A

Red

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17
Q

What colour flame does a barium Ba2+ ion produce?

A

Green

18
Q

What is the sodium hydroxide precipitation reaction a test for?

A

Metal ions

19
Q

What colour precipitate do calcium Ca2+ ions produce in a precipitation reaction with sodium hydroxide?

A

White

20
Q

What colour precipitate do copper(II) Cu2+ ions produce in a precipitation reaction with sodium hydroxide?

A

Blue

21
Q

What colour precipitate do iron(II) Fe2+ ions produce in a precipitation reaction with sodium hydroxide?

A

Green

22
Q

What colour precipitate do iron (III) Fe3+ ions produce in a precipitation reaction with sodium hydroxide?

A

Brown

23
Q

What colour precipitate do aluminium Al3+ ions produce in a precipitation reaction with sodium hydroxide?

A

White, and then dissolves again in excess to produce a colourless solution.

24
Q

What colour precipitate do magnesium Mg2+ ions produce in a precipitation reaction with sodium hydroxide?

A

White

25
Q

What is the ionic reaction between calcium and sodium hydroxide solution?

A

Ca2+ (aq) + 2OH- (aq) -> Ca(OH)2 (s)

26
Q

What is the ionic reaction between copper(II) and sodium hydroxide solution?

A

Cu2+ (aq) + 2OH-(aq) -> Cu(OH)2(s)

27
Q

What is the ionic reaction between iron(II) and sodium hydroxide solution?

A

Fe2+(aq) + 2OH-(aq) -> Fe(OH)2(s)

28
Q

What is the ionic reaction between iron(III) and sodium hydroxide solution?

A

Fe3+(aq) + 3OH-(aq) -> Fe(OH)3(s)

29
Q

What is the ionic reaction between aluminium and sodium hydroxide solution?

A

Al3+(aq) + 3OH-(aq) -> Al(OH)3(s)

Al(OH)3(s) + OH- -> Al(OH)4(-)

30
Q

What is the ionic reaction between magnesium and sodium hydroxide solution?

A

Mg2+(aq) + 2OH-(aq) -> Mg(OH)2(s)

31
Q

How does one test for carbonate ions?

A

Place the substance in an acid and put the resultant gas in limewater. The limewater will turn cloudy if carbonate ions are present.

32
Q

How does one test for halide ions?

A

Add dilute nitric acid (HNO3) follow by silver nitrate solution (AgNO3).

33
Q

What colour precipitate do chloride ions form when reacted with dilute nitric acid and silver nitrate solution?

A

White

34
Q

What colour precipitate do bromide ions form when reacted with dilute nitric acid and silver nitrate solution?

A

Cream

35
Q

What colour precipitate do iodide ions form when reacted with dilute nitric acid and silver nitrate solution?

A

Yellow

36
Q

What is the ionic equation for the reaction between chloride ions and silver ions?

A

Ag+(aq) + Cl-(aq) -> AgCl(s)

37
Q

What is the ionic equation for the reaction between bromide ions and silver ions?

A

Ag+(aq) + Br-(aq) -> AgBr(s)

38
Q

What is the ionic equation for the reaction between iodide ions and silver ions?

A

Ag+(aq) + I-(aq) -> AgI(s)

39
Q

How does one test for sulphate ions?

A

By adding dilute hydrochloric acid (HCl) followed by barium chloride solution (BaCl2). A white precipitate should form of barium sulphate.

40
Q

What is the ionic equation for the reaction between barium ions and sulphate ions?

A

Ba2+(aq) + SO4 2-(aq) -> BaSO4(s)

Chemistry - Unit Three (6 decks)

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