Unit 3- Chemistry in Society Flashcards

1
Q

What is metallic bonding?

A

Metallic bonding is the electrostatic force of attraction between positively charged ions and delocalised electrons.

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2
Q

Do metals conduct electricity?

A

Yes

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3
Q

Why do metals conduct electricity?

A

Metallic elements are conductors of electricity because they contain delocalised electrons.

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4
Q

What structure does metallic bonding form?

A

Metallic lattice

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5
Q

What does a metallic lattice look like?

A

Positive metal ions with delocalised electrons free to move in the gaps between.

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6
Q

Metal + oxygen —>

A

metal oxide

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7
Q

Copper + oxygen —>

A

copper oxide

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8
Q

Metal + water —>

A

Metal hydroxide + hydrogen

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9
Q

Sodium + water —>

A

Sodium hydroxide + hydrogen

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10
Q

Metal + acid —>

A

Salt + hydrogen

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11
Q

Zinc + hydrochloric acid —>

A

Zinc chloride + hydrogen

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12
Q

What is an ion electron equation?

A

An equation that shows either the loss of electrons (oxidation) or the gain of electrons (reduction).

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13
Q

OIL RIG stands for…

A

Oxidation
Is
Loss of electrons

Reduction
Is
Gain of electrons

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14
Q

How to know if an ion electron equation is reduction or oxidation:

A

In an ion electron equation, if the electrons ore on the left hand side of the arrow (reduction). If they are on the right hand side of the arrow (oxidation).

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15
Q

The electrochemical series is arranged in order of…

A

Increasing reactivity

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16
Q

What is a redox reaction?

A

A redox reaction is a reaction which both reduction and oxidation takes place. Electrons are lost by one substance and gained by another.

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17
Q

Method for writing redox equations:

A

1) Decide what is being oxidised and what is being reduced, write the ion electron equation for both.

2) Multiply through so the number of electrons being lost (oxidation) is the same as the number of electrons being gained (reduction).

3) Combine the ion electron equations and cancel the electrons.

4) If you’ve done this correctly the total charge should be the same on either side.

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18
Q

Redox reaction notes:

A

Electrons do not appear in the overall redox equation.

The total charge on each side of the same.

The metal which is higher in the electrochemical series will become oxidised.

In each of the examples the negative ions present in the solutions have not been included or even referred to since they do not take part in the reaction. They are known as spectator ions.

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19
Q

What is a metal ore?

A

A rock that contains a metal compound.

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20
Q

What do miners call metal compounds?

A

Minerals

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21
Q

The ease at which a metal can be extracted from its metal compound depends on…

A

The metal’s reactivity.

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22
Q

What happens during the extraction of metals?

A

Metal ions are reduced (gain electrons) forming metal atoms.

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23
Q

Methods of extraction:

A

Heat alone (for extraction of Ag, Au and Hg)

Heating with carbon or carbon monoxide (for extraction of Cu, Pb, Sn, Fe and Zn)

Electrolysis (for extraction of more reactive metals including aluminium)

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24
Q

What is electrolysis?

A

The decomposition of an ionic compound into its elements using electricity.

A d.c. supply must be used if the products of electrolysis are to be identified.

Positive ions gain electrons at the negative electrode and negative ions lose electrons at the positive electrode.

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25
Q

How to make a simple cell?

A

A simple cell can be made by placing two metals in an electrolyte.

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26
Q

What is an electrolyte?

A

An electrically conducting solution containing ions.

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27
Q

What is a half-cell?

A

Metals in solution of their own ions.

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28
Q

What is an ion bridge (salt bridge)?

A

Filter paper soaked in sodium chloride solution.

An ion bridge can be used to like half-cells. Ions can move across the bridge to complete an electrical circuit.

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29
Q

How do electrons flow in electrochemical cells?

A

Electrons flow in the wires from the species higher in the electrochemical series to the one lower in the electrochemical series.

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30
Q

How to increase/decrease the voltage in an electrochemical cell?

A

In an electrochemical cell, different combinations of metal electrodes will affect the voltage.

The bigger the gap between the two metals on the electrochemical series, the bigger the voltage.

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31
Q

Advantages of plastics:

A

Unreactive
Durable
Cheap
Waterproof
Reusable

32
Q

What is a polymer?

A

A giant molecule made by joining many small molecules together.

Polymers are made from smaller units called monomers which join together via a chemical reaction called polymerisation.

33
Q

How to name a polymer?

A

Put the name of the monomer in brackets and then put “poly” in front of it.

34
Q

Shape of monomers?

A

Rugby goal post shape with the carbon to carbon double bond in the middle.

35
Q

What is addition polymerisation?

A

The name given to a chemical reaction in which unsaturated monomers are joined, forming a polymer.

36
Q

Do monomers contain a C=C double bond?

A

Yes

37
Q

What is a repeating unit?

A

The shortest section of a polymer chain which, if repeated, would yield the complete polymer chain.

38
Q

What to remember when drawing a repeating unit?

A

Remember to add the bond on either side coming from the carbons that would allow them to join to other monomers.

39
Q

To be healthy, plants/crops need how many different chemicals?

A

16

40
Q

What are the 3 most important elements needed for a plant/crop to be healthy?

A

Nitrogen, Phosphorus, Potassium (NPK)

41
Q

What is the use of fertilisers?

A

Fertilisers increase crop production by replacing essential elements in the soil used by a previous crop or by boosting levels of such elements.

42
Q

Are fertilisers water-soluble?

A

Yes

43
Q

Why must fertilisers be water-soluble?

A

They must be able to dissolve in water so that plants can absorb them through their roots.

44
Q

Why are ammonia and nitric acid important?

A

Ammonia and nitric acid are important compounds used to produce soluble, nitrogen-containing salts that can be used as fertilisers.

45
Q

Ammonia properties?

A

Ammonia is a pungent, clear, colourless gas which dissolves in water to form an alkaline solution.

46
Q

Ammonia solutions react with acids to form…

A

Soluble salts

47
Q

Ammonia solution + acid —>

A

Ammonium salt + water

48
Q

Ammonia chemical formula:

A

NH3

49
Q

Nitric acid chemical formula:

A

HNO3

50
Q

Haber process involves?

A

The production of ammonia using an iron catalyst.

51
Q

Otswald process involves?

A

The production of nitric acid using a platinum catalyst.

52
Q

Where does nuclear radiation come from?

A

The nucleus of an atom.

53
Q

Substances that give out nuclear radiation are said to be…

A

Radioactive

54
Q

How can unstable nuclei (radioisotopes) become more stable?

A

By giving out radiation.

55
Q

Types of radiation:

A

Alpha

Beta

Gamma

56
Q

Alpha radiation description:

A

Identical to a helium nucleus. Can be represented as:

4
He
2

57
Q

Mass and charge of alpha radiation:

A

Mass: 4

Charge: +2

58
Q

Penetrating power of alpha:

A

Can be stopped by a sheet of paper.

59
Q

Beta radiation description:

A

Beta particles are electrons produced in the nucleus of an atom.

60
Q

Mass and charge of beta radiation:

A

Mass: negligible

Charge: -1

61
Q

Penetrating power of beta:

A

Can pass through a sheet of paper, but absorbed by a thin sheet of metal.

62
Q

Gamma radiation description:

A

These are electromagnetic waves which have an even shorter wavelength than X-rays.

63
Q

Mass and charge of gamma radiation:

A

Mass: 0

Charge: 0

64
Q

Penetrating power of gamma:

A

They can travel long distances in air and can only be stopped by thick layers of concrete or lead.

65
Q

What are nuclear equations?

A

Nuclear equations are used as a way of showing the change that takes place in the nucleus of a radioisotope.

66
Q

What happens when an isotope emits an alpha particle?

A

The atomic number of the isotope decreases by 2 and the mass number decreases by 4.

67
Q

What happens when an isotope emits a beta particle?

A

The atomic number of the isotope increases by 1 and the mass number stays the same.

68
Q

What happens when an isotope emits gamma rays?

A

The atomic number and the mass number of the isotope stay the same.

69
Q

What to remember when writing nuclear equations?

A

When the atomic number of an isotope changes, the symbol also changes.

70
Q

What is half-life?

A

The time in which the activity of a radioisotope decays by half, or in which half of its atoms disintegrate.

71
Q

Half-life key point:

A

Half-lives can vary from seconds to millions of years and are independent of the presence of catalysts or the chemical state of the isotope.

72
Q

What to remember when calculating half-life?

A

The number of arrows = the number of half-lives that have passed.

73
Q

Use of radioisotopes in medicine:

A

Cobalt-60 is an artificially produced isotope that carries excess energy. It emits gamma rays to form a lower energy version of the same isotope, and is none of several isotopes used in radiotherapy to destroy cancer cells.

74
Q

What is a flame test?

A

Some metals will produce a distinctive colour when they are held at the edge of a blue Bunsen flame.

75
Q

Why do metal compounds produce coloured flames?

A

Due to the presence of the metal ions in the compound.

76
Q

How to calculate percentage mass?

A

Percentage mass = portion/total x 100