C4 Flashcards

1
Q

metal carbonate + acid –> ______ +__________ + ______

A

salt + water + CO2

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2
Q

metal + acid –> _____+____

A

salt + hydrogen

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3
Q

acid + metal oxide —> ___+ ___

A

salt + water

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4
Q

what does oxidation mean?

A

the gain of oxygen
- the substance that gains oxygen has been oxidised

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5
Q

what does reduction mean?

A

the loss of oxygen
- the substance that lost oxygen has been reduced

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6
Q

PRACTICAL: making pure dry copper sulphate crystals

A
  1. measure 25cm^3 of sulfuric acid
  2. heat gently on bunsen burner, tripod, gauze and heat proof mat
  3. remove solution from bunsen burner and add copper oxide to acid with spatula and stir
  4. add excess copper oxide until no more will dissolve
  5. filter the mixture with filter paper, filter funnel and conical flask
  6. pour filtered solution into evaporating basin
  7. leave to dry in cool pace for 24 hours
  8. remove crystals from solution with a spatula
  9. gently pat crystals with filter paper
  10. you now have pure dry crystals of copper sulphate
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7
Q

what is oxidation in terms of electrons?

A

the loss of electrons

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8
Q

what is reduction in terms of electrons?

A

the gain of electrons

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9
Q

what is an ore?

A

a rock that contains a metal compound

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10
Q

what are bases?

A

chemicals that neutralise acids

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11
Q

what do bases produce?

A

a salt and water

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12
Q

what do acids produce in aqueous solutions?

A

hydrogen ions (H+ ion)

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13
Q

what are bases that are soluble in water also called?

A

alkalis

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14
Q

what do alkalis produce in aqueous solutions?

A

hydroxide ions (OH-)

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15
Q

which metals are extracted by heating with carbon?

A

metals less reactive than carbon

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16
Q

which metals are extracted by electrolysis?

A

metals more reactive than carbon

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17
Q

what 5 are signs a chemical reaction has taken place?

A
  1. fizzing
  2. colour change
  3. temperature change
  4. formation of a precipitate
  5. change in smell
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18
Q

what happens in displacement reaction?

A

a more reactive element will displace a less reactive element and form a compound

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19
Q

what ion do all salts have?

A

a positive ion

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20
Q

what is an acid?

A

a substance that releases H+ ions into solutions

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21
Q

what is an alkali?

A

a substance that release OH- ions into solutions

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22
Q

practical: why do you heat the acid gently first when making a salt?

A

to speed up the reaction

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23
Q

practical: why do you stir the solution after adding each spatula of metal oxide?

A

to make sure it’s fully neutralised

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24
Q

practical: what observation would be made when a metal oxide can no longer react with an acid?

A

the insoluble metal oxide remained in the beaker

25
Q

what do strong acids do in solutions?

A

fully ionise

26
Q

what are 3 examples of strong acids?

A

hydrochloric acid, sulfuric acid, nitric acid

27
Q

what do weak acids do in solutions?

A

partially ionise in solutuion

28
Q

what are some examples of weak acids?

A

methanoic acid and ethanoic acid (vinegar)

29
Q

concentrated acids have…

A

have a larger number of acid particles per volume of water

30
Q

Dilute acids (less concentrated) have…

A

a smaller number of acid particles per volume of water

31
Q

what does a lower pH means in terms of hydrogen ion concentration?

A

lower pH = lower hydrogen ion concentration

32
Q

what is electrolysis?

A

splitting up with electricity

33
Q

what does electrolysis do?

A

separates elements in insoluble ionic compounds

34
Q

electrolysis: what are electrodes

A

solid conductors that are generally made of metal or carbon

35
Q

electrolysis: where are the electrodes placed and what are they connected to?

A
  • place in a liquid (electrolyte)
  • connected to a wire
36
Q

what is an electrolyte?

A

a liquid or solution that contains an ionic compound that is molten or dissolved (is free to move)

37
Q

what are the positive and negative electrodes called?

A

positive: anode
negative: cathode

38
Q

what are cations and anions?

A

cations = positively charged ions (metals)
anions = negatively charged ions (non- metals)

39
Q

electrolysis: why is the electrode connected to a wire?

A

so that the electrons can flow between them

40
Q

electrolysis: why do you need to add a power supply (e.g a battery)

A
  • to drive the flow of electrons
    battery is used to pass an electric current through the electrolyte
41
Q

why do solid ionic compounds not conduct electricity?

A

because their ions are held in place by strong electrostatic forces of attraction so the ions can’t move

42
Q

what happens when an ionic compound in melted or dissolved in water?

A

the forces of attractions are broken and the ions are free to move

43
Q

electrolysis: what is the negative cathode attached to?

A

the negative terminal of the power pack

44
Q

electrolysis: what is the positive anode attached to?

A

the positive terminal of the powerpack

45
Q

why is electrolysis expensive?

A

melting compounds with high melting and boiling points requires a great deal of energy.
- a lot of energy is needed to produce an electric current

46
Q

what do water molecules form when they are ionised?

A

hydrogen and hydroxide ions

47
Q

electrolysis: when is hydrogen produced at the cathode?

A

if the metal is more reactive than hydrogen

48
Q

what does aqueous mean?

A

dissolves in water

49
Q

electrolysis: what happens if the aqueous solution contains halide ions?

A

the halogen will be produced at the anode

50
Q

electrolysis: how can we tell if a gas being produced is a chlorine gas?

A

if we hold a piece of damp blue litmus paper near the anode and it becomes bleached

51
Q

why is cyrolite used to dissole (the alluminium oxide)

A

because it has melting point of over 2000 degrees so it reduces the cost of heating

52
Q

what must the electrodes be made of?

A

unreactive/ inert metals/elements
e,g graphite and platinum

53
Q

why do electrodes have to be replaced every few months?

A

because it burns away

54
Q

what is an acid?

A

a substance that produces H+ ions into solutions

55
Q

what is an acid?

A

a substance that produces H+ ions into solutions

56
Q

what uis

A
57
Q
A
58
Q

Dont have the steps for electrolysis required practical

A