C3.4 Analysis and Synthesis Flashcards

1
Q

State the colour for the flame test of a Lithium Ion (Li+)

A

Crimson/red

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2
Q

State the colour for the flame test of a Sodium Ion (Na+)

A

Orange

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3
Q

State the colour for the flame test of a Potassium Ion (K+)

A

Lilac/Purple

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4
Q

State the colour for the flame test of a calcium ion (Ca2+)

A

red

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5
Q

State the colour for the flame test of a Barium Ion (Ba2+)

A

Green

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6
Q

State the observation when a few drops of sodium hydroxide is added to iron (II) chloride

A

green precipitate/solid

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7
Q

State the observation when a few drops of sodium hydroxide is added to iron (III) chloride

A

brown precipitate/solid

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8
Q

State the observation when a few drops of sodium hydroxide is added to copper chloride

A

blue precipitate/solid

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9
Q

State the observation when a few drops of sodiurecipitate/solidm hydroxide is added to calcium chloride

A

white precipitate/solid

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10
Q

State the observation when a few drops of sodium hydroxide is added to magnesium chloride

A

white precipitate/solid

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11
Q

State the observation when a few drops of sodium hydroxide is added to aluminium chloride

A

white precipitate/solid

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12
Q

State the observation when an excess of sodium hydroxide is added to aluminium chloride

A

precipitate dissolves/disappears

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13
Q

Describe how to distinguish between calcium and magnesium ions

A

flame test

calcium ions give a red flame

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14
Q

Describe the test for carbonate ions

A

Add an acid
Bubbles
of carbon dioxide
which turns limewater cloudy

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15
Q

Describe the test for sulphate ions

A

Add barium chloride

makes a white precipitate (solid)

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16
Q

Describe the test for chloride ions

A

Add silver nitrate

makes a white precipitate (solid)

17
Q

Describe the test for bromide ions

A

Add silver nitrate

makes a cream precipitate (solid)

18
Q

Describe the test for iodide ions

A

Add silver nitrate

makes a yellow precipitate

19
Q

Give two advantages of using instrumental methods of analysis. [1]

A

fast
sensitive
accurate

20
Q

Describe how to use apparatus to do a titration using 25 cm3 of dilute hydrochloric acid.
In your answer you should include:
• how you will determine the end point of the titration
• how you will make sure the result obtained is accurate. [4]

A
  • put sodium hydroxide (alkali) in the burette
  • add drop wise until the indicator turns pink
  • whilst swirling
  • read at the meniscus
  • read the start and end volumes
21
Q

What is meant by a closed system?

A

nothing can enter and nothing can leave the reaction

22
Q

Explain why, when a reversible reaction reaches equilibrium, the reaction appears to have stopped. [2]

A

forward and backward reactions have same rate [1]

so there is no (overall) change in concentration of reactants and products [1]

23
Q

Name a natural resource from which hydrogen is produced for the Haber process

A

methane (natural gas)

24
Q

What happens to the amount of ammonia produced at equilibrium if the pressure is increased?
Give a reason for your answer. [2]

A
the amount (of ammonia) increases [1]
the equilibrium moves to the side (of the equation) with fewer (gaseous) molecules / moles [1]
25
Q

Why is a temperature much lower than 450 °C not used for the Haber process? [1]

A

rate of reaction (too) slow [1]

26
Q

Explain how ammonia is separated from unreacted nitrogen and hydrogen in the Haber process [2]

A

(gases) cooled [1]

ammonia condensed [1]

27
Q

State and explain how a decrease in temperature would affect the yield of ammonia at equilibrium [2]

A

increase yield [1]

because (forward) reaction is exothermic [1]

28
Q

Name a natural resource from which nitrogen is obtained for the Haber process

A

air

29
Q

Name the catalyst used in the Haber process

A

Iron

30
Q

Explain why high pressures need to be compromised in the Haber process

A

too expensive to maintain/requires large amounts of energy