Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry > C4 - Chemical changes > Flashcards

C4 - Chemical changes Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What is an ore?

A

Rocks containing enough metal to be worth extracting.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is electrolysis?

A

Splitting an ionic compound into simpler substances using an electric current.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When do we use electrolysis?

A

When our metal is more reactive than carbon. When are substance contains ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is an electrolyte?

A

Liquid containing ions. Must be able to conduct electricity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a Cathode?

A

Connects to the negative side of the battery (the negative electrode). Attracts cations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an anode?

A

Connects to the positive side of the battery (the positive electrode). Attracts anions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why do we melt or dissolve the solution in water?

A

To allow ions to flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does water split into?

A

hydrogen ions (H+) and hydroxide ions (OH-)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the positive ions in CuSO4 when it is dissolved in water?

A

Cu(charge)2+ and H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the negative ions formed at the anode in CuSO4 when it is dissolved in water?

A

SO4 (charge)2- and OH-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the rule for what forms at the cathode (-)?

A

The less reactive positive ion forms here.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the rule for what forms at the anode(+)?

A

Oxygen forms unless a halide ion is present. (Group 7 element)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why does CO2 form in electrolysis?

A

Oxygen formed from electrolysis reacts with the graphite anode, forming carbon dioxide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When does a neutralisation reaction occur?

A

When an acid and an alkali react together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the word equation for a neutralisation reaction?

A

Acid + Alkali -> Salt + Water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What do all acids contain?

A

H+ ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do all alkalis contain?

A

OH- ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What determines if an acid or alkali is weak or strong?

A

How ionised it is in water.
Weak acid/alkali - only partially ionised in water
Strong acid/alkali - 100% or fully ionised in water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is oxidation?

A

When a substance loses electrons. (gains oxygen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is reduction?

A

When a substance gains electrons. (loses oxygen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the reactivity series of metals?

A

Shows the metals in order of reactivity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What groups react with water?

A

Mostly Group 1 metals and Group 2 metals react with water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How are metals more reactive than carbon extracted?

A

Electrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why must an ionic substance have been melted or dissolved in water?

A

So ions are free to move.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What happens in electrolysis?

A

Positively charged ions move to the negative electrode. They gain electrons and are reduced.

Negatively charged ions move to the positive electrode. They lose electrons and are oxidised.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why are carbon electrodes chosen?

A

Carbon electrodes are chosen because they have a high melting point and they do not react with the reactants and the products (they are inert).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the general equation for the reaction between metal carbonate and an acid?

A

Metal carbonate + acid -> salt + water + co2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the general equation for the reaction between metal oxides/hydroxides and an acid?

A

metal oxide/hydroxide + acid -> a salt + water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What do acids and alkalis produce in an aqueous solution?

A

Acids produce hydrogen ions. Alkalis produce hydroxide ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

State the general equation for a neutralisation reaction in short ionic form.

A

H+ + OH- -> H20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How is aluminium manufactured and why is it expensive?

A

It is made through the electrolysis of cryolite and aluminium oxide.
It is expensive because lots of energy is needed to produce the current.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Why is cryolite used in the extraction of aluminium?

A

Because it lowers the melting point of aluminium oxide. Reducing energy costs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are the half equations in the extraction of aluminium?

A

Al(3+) + 3e- -> Al (cathode)
2O(2-) -> O2 + 4e- (anode)
Oxygen reacts with carbon at the anode forming C02

34
Q

What is a redox reaction?

A

A reduction or oxidation reaction.

35
Q

What is an ionic equation?

A

Where you only show the particles that are oxidized or reduced. e.g. Ca + Fe(2+) –> Ca(+) + Fe

36
Q

What are ionic half equations?

A

Focuses on the ionic change of one particular element. e.g. Fe(2+) + 2e(-) –> Fe

37
Q

What are the products when calcium hydroxide and hydrochloric acid react?

A

Calcium chloride + water

38
Q

What is used to measure the unknown volume in a titration?

A

Burette

39
Q

Why are trains powered by hydrogen fuel cells being referred to as the new steam trains?

A

In hydrogen fuel cells hydrogen goes to the positive electrode where it loses electrons and is, therefore, oxidized. This means it produces water.

40
Q

Why must the positive electrode be continually replaced during the production of aluminium?

A

The carbon electrode reacts with the oxygen formed at the anode, which produces carbon dioxide. Meaning the electrode will corrode.

41
Q

Why can’t sodium chloride solution be used as the electrolyte to produce sodium metal?

A

The less reactive metal will from at the positive electrode.
Meaning hydrogen will form instead of sodium.

42
Q

Why do alkaline batteries eventually stop working?

A

A reactant is being used up

43
Q

Why can alkaline batteries not be recharged?

A

The reaction is not reversible.

44
Q

What is a cell?

A

A cell is composed of two electrodes dipped in an electrolyte solution. It creates a current from a chemical reaction.

45
Q

How are metals less reactive than carbon extracted.

A

Reduction with carbon. Carbon displaces the metal in a metal oxide. Leaving the metal in it’s pure form.

46
Q

What is the general equation for a reaction between metals and acids?

A

Metal + acid -> salt + hydrogen

47
Q

Which metals in the reactivity series will react with an acid?

A

Those above hydrogen.

48
Q

State a neutralisation reaction in ionic form.

A

H+ + OH- -> H2O

49
Q

Where does reduction occur in electrolysis?

A

Cathode

50
Q

Where does oxidation occur in electrolysis?

A

Anode

51
Q

How is aluminium manufactured?

A

Electrolysis of aluminium oxide and cryolite.

52
Q

Why is manufacturing aluminium expensive?

A

Lots of energy needed to produce the current.

53
Q

What is the difference between a chemical cell and electrolysis?

A

Electrolysis uses electricity to produce a chemical reaction.
A chemical cell uses a chemical reaction to produce electricity.

54
Q

Why is graphite used as an electrode?

A

Conducts electricity.
Inert (unreactive)

55
Q

Why does the metal in electrolysis need to be more reactive than carbon?

A

So it doesn’t get displaced by carbon.

56
Q

What is an alkali?

A

A base that dissolves in water to form a solution with a pH greater than 7.

57
Q

What is a base?

A

Any substance with a pH greater than 7.

58
Q

What are 3 common acids?

A

Nitric
Sulfuric
Hydrochloric

59
Q

What are 3 common bases?

A

Metal Carbonate
Metal Hydroxide
Metal oxide

60
Q

How should we evaporate the water in crystallisation and why?

A

Water bath/ electric heater
To avoid damaging the salt

61
Q

Why is a pipette and a burette used in a titration?

A

Pipette used to measure fixed volume.
Burette used to measure variable volume.

62
Q

Give 4 factors that affect the voltage produced by a cell.

A

Type of electrode.
Type of electrolyte.
Concentration of electrolyte
Temperature.

63
Q

What is a cell?

A

A cell is composed of two electrodes dipped in an electrolyte solution. It produces current from a chemical reaction.

64
Q

What is a battery?

A

Two or more cells connected in series.

65
Q

Explain rechargeable batteries.

A

Chemical reactions are reversed when external current is supplied.

66
Q

Explain non-rechargeable batteries.

A

All reactants are used up, cannot be recharged.

67
Q

What is a fuel cell?

A

Fuel cells consist of fuel and oxygen. Where the fuel is oxidised to produce electricity.

68
Q

What is a hydrogen fuel cell?

A

Where hydrogen is oxidised to form water.

69
Q

Why should batteries not be put in household waste?

A

Alkaline waste can be harmful / toxic / corrosive.

70
Q

What are the adv. of alkaline cells?

A

Cheap to manufacture.

71
Q

What are the disadv. of alkaline cells?

A

Expensive to recycle.
Toxic waste.
May end up in landfill sites.

72
Q

What is the overall equation for a hydrogen fuel cell?

A

Hydrogen + oxygen -> water

73
Q

What is the difference between hydrogen fuel cells and electrolysis?

A

Electrolysis - anode is positive and cathode is negative
Hydrogen fuel cells - cathode is positive and anode is negative

74
Q

What is the anode in both electrolysis and hydrogen fuel cells?

A

Where electrons are lost.

75
Q

Difference between an alkali and a base.

A

Alkali is an soluble metal hydroxide, a base is a insoluble metal hydroxide or metal oxide.

76
Q

What are all the charges of ions from acids?

A

Hydrochloric acid - Cl-
Nitric acid - NO3-
Sulfuric acid - SO42-

77
Q

What happens when the concentration of H+ ions increases by a factor of 10?

A

pH decreases by 1 unit.

78
Q

What forms from a metal + acid?

A

Salt + hydrogen

79
Q

How can soluble salts be made?

A

By reacting acids with insoluble solids such as metal, metal oxide, metal hydroxide and metal carbonate.

80
Q

How are metal oxides made?

A

Metal + oxygen

Chemistry (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions