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C2 Flashcards

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1
Q

What are ions?

A

Ions are charged particles

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2
Q

What happens when metals form ions?

A

When metals form ions they loose electrons from their outer shell to form positively charged ions (cations)

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3
Q

What happens when non-metals form ions?

A

When non-metals form ions, they gain electrons into their outer shell to form negatively charged ions (anions)

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4
Q

Why do the ions produced by g1, g2 and g6,g7 have a noble gas structure?

A

Because they have full outer shell of electrons (very stable)

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5
Q

What is ionic bonding?

A

Ionic bonding is when the oppositely charged ions from the metal and non-metal are strongly attracted to each other by electrostatic forces.

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6
Q

What is an ionic compound?

A

An ionic compound is a giant ionic structure of ions.

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7
Q

What is a giant ionic lattice structure in ionic compounds?

A

It is where there are strong electrostatic forces of attraction in all directions between oppositely charged ions.

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8
Q

What are the limitations of using a dot and cross diagram to represent a giant ionic structure?

A

They don’t tell us about the shape of the molecule.

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9
Q

What are the limitations of using 2 dimensional diagrams to represent a giant ionic structure?

A

-We cant tell which electron in the bond came from what atom,
-we have no idea about outer electrons in the bonds
-they don’t give us accurate information about the shape of the molecule.

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10
Q

What are the limitations of ball and stick diagrams to represent a giant ionic structure?

A

The ions are shown as widely spaces but they are actually packed together.
They only show a small part of the giant lattice ( mistaken impression of the size of the structure)

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11
Q

Why do ionic compounds have high melting and boiling points?

A
  • High melting and boiling points bc of the large amounts of energy needed to break the many strong bonds
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12
Q

When do ionic compounds conduct electricity?

A

Ionic compounds conduct electricity when they are molten (liquid) or when aqueous (dissolved in water) because their ions are free to move and so charge can flow.

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13
Q

How do you work out the empirical formula of an ionic compound from a dot and cross diagram?

A

Count up how many atoms there are of each element.

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14
Q

How do you work out the empirical formula of an ionic compound from a 3D diagram of a ionic lattice?

A

1) Work out the ions
2) Balance the charges of the ions so that the overall charge of the compounds is zero

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15
Q

What is covalent bonding?

A

When non-metal atoms bond together, sharing pairs of electrons.

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16
Q

What does covalent bonding happen in?

A

Covalent bonding happens in compounds of non-metals and in non-metal elements.

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17
Q

Why are covalent bonds very strong?

A

The positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces making the bonds very strong.

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18
Q

What are the limitations of using a dot and cross diagram in a covalent bond?

A

They don’t show the relative sizes of the atoms or how the atoms are arranged in space.

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19
Q

Limitations of using displayed formula (single lines between atoms) to show a covalent bond?

A

They don’t show the 3D structure of the molecule or which atoms the electrons in the covalent bond have come from.

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20
Q

Limitations off using 3D models to show covalent bonds?

A

Can get confusing for large molecules when there are lots of atoms and they don’t show where the electrons in the bonds have come from.

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21
Q

How do you find the molecular formula of a simple molecular compound?

A

By counting up how many atoms of each element there are.

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22
Q

What structure do substances containing covalent bonds have?

A

Simple molecular structures

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23
Q

What are most simple molecular substances at room temp?

A

Gases or liquids

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24
Q

In simple molecular structures what are the atoms within the molecules held together by and what are the forces of attraction like?

A

The atoms within the molecules are held together by strong covalent bonds but the forces of attraction between these molecules are very weak.

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25
Q

What do u need to do to melt or boil a simple molecular compound how does this affect the bp and mp?

A

You only need to break the intermolecular forces and not the covalent bonds, therefore the melting and boiling points are very low bc the particles are easily parted from each other.

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26
Q

What happens as simple molecules (covalent bonds) get bigger?

A

As molecules get bigger, the strength of the intermolecular structures increases, so more energy is needed to break them and so the melting and boiling point increase.

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27
Q

Why do molecular substances not conduct electricity?

A

The molecules don’t have an overall electric charge and no free electrons or ions.

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28
Q

What are polymers?

A

Where lots of small units (monomers) are linked together to form a long molecule that has repeating units.

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29
Q

What are atoms in a polymer joined together by?

A

By strong covalent bonds

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30
Q

Why are polymers solids at room temperature?

A

The intermolecular forces between polymer molecules are relatively strong so more energy is needed to break them so they are solid at room temp.

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31
Q

What are atoms bonded together by in giant covalent structures?

A

All the atoms are bonded together by strong covalent bonds.

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32
Q

What state are substances that consist of giant covalent structures and why? (properties)

A

They’re solids with very high melting and boiling points as lots of energy is needed to break the covalent bonds between the atoms.

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33
Q

What are the main examples of giant covalent structures?

A

-Diamond
-Graphite
-Silicon dioxide (silica)

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34
Q

What are some allotropes (different structural forms of the same element in the same physical state) of carbon?

A

Diamond
Graphite (graphene)
Fullerenes

35
Q

What are the properties of carbons?

A

-really hard
-very high melting point
-doesn’t conduct electricity

36
Q

Why is diamond really hard?

A

Diamond has a giant covalent structure made up of carbon atoms that each form 4 covalent bonds, making it really hard.

37
Q

Why does diamond have a very high melting point?

A

The strong covalent bonds take a lot of energy to break and give diamond a very high melting point.

38
Q

Why doesn’t diamond conduct electricity?

A

Because it has no free electrons or ions.

39
Q

What happens in graphite (what is formed)?

A

In graphite each carbon atom forms 3 covalent bonds with 3 other carbon atoms, forming layers of hexagonal rings which have no covalent bonds bewteen layers

40
Q

Why is graphite soft and slippery and what does this make it ideal for?

A

Graphite is soft and slippery because there are no covalent bonds between the layers because they’re only held together weakly and are free to move over each other.
Ideal as a lubricating material.

41
Q

Why has graphite got a high melting point?

A

The covalent bonds in the layers need lots of energy to break.

42
Q

Why does graphite conduct electricity and thermal energy?

A

Only 3 out of each carbons 4 outer electrons are used in bonds, so each carbon atom has 1 electron that’s delocalised (free) and can move so graphite conducts electricity and thermal energy.

43
Q

What is graphene?

A

Graphene is a single (one) layer of graphite.

44
Q

Why is graphene strong and light?

A

The arrangement of covalent bonds make it very strong.
Its light so it can be added to composite material to improve their strength without adding much weight.

45
Q

Why can graphene be used in electronics?

A

Like graphite, it contains delocalised electrons so can conduct electricity through the whole structure and is useful in electronics.

46
Q

What are fullerenes?

A

Fullerenes are molecules of carbon atoms with hollow shapes.

47
Q

What is the structure of fullerenes?

A

Its mainly carbon atoms arranged in hexagons but can also contain pentagons (rings with 5 carbon atoms) or heptagons (rings of 7 carbon atoms).

48
Q

What was the first fullerene to be discovered and what shape is it?

A

Buckminsterfullerene (C60) forms a hollow sphere (spherical shape)

49
Q

What are the uses of fullerenes?

A

-Deliver a drug into the body (fullerene structure form around another atom or molecule which is then trapped inside)
-Industrial catalysts (huge surface area)
-Used as Lubricants

50
Q

What can fullerenes form and what is there length to diameter ratio like?

A

Fullerenes can form nanotubes (tiny carbon cylinders).
Carbon nanotubes have a very high length to diameter ratio.

51
Q

Uses and properties of nanotubes?

A

-Conduct electricity and thermal energy (heat)
-High tensile strength (don’t break when stretched)
-Nanotechnology - used in electronics or to strengthen materials without adding much weight (eg tennis racket frames)

52
Q

What do metals consist of?

A

Metals consist of giant structures of atoms arranged in a regular pattern.

53
Q

What happens to the electrons in outer shells of metals?

A

The electrons in the outer shell of metal atoms are delocalised and so are free to move through the whole structure.

54
Q

What do the forces of attraction in metals do (Metallic bonding)?

A

There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons which hold the atoms together in a regular structure aka metallic bonding which is very strong.

55
Q

Why do most metals have high melting and boiling points?

A

The electrostatic forces between the metal atoms and the delocalised sea of electrons are very strong and need lots of energy to be broken down meaning most compounds with metallic bonds have very high mps and bps so they’re generally solid at room temp.

56
Q

Why are metals malleable and what does this allow them to do?

A

The layers of atoms in a pure metal can slide over each other, making metals malleable allowing them to be bent and shaped.

57
Q

Why are alloys better than pure metals?

A

Pure metals are too soft for many uses so are mixed with other metals to make alloys which are harder.

58
Q

Why are alloys harder than pure metals?

A

Different metals have diff sized atoms so when another element is mixed with a pure metal, the new metal will distort the layers of metal atoms, making it more difficult for them to slide over, hence alloys are harder than pure metals.

59
Q

Why are metals good conductors of electricity?

A

Metals are good conductors of electricity because the delocalised electrons in the metal carry electrical charge through the metal.

60
Q

Why are metals good conductors of thermal energy?

A

Metals are good conductors of thermal energy because energy is transferred by the delocalised electrons.

61
Q

What are the 3 states of matter?

A

Solid, liquid, gas.

62
Q

What does which state something is at a certain temperature depend on?

A

Depends on how strong the forces of attraction are between the particles of the substance.

63
Q

What 3 things to how strong the forces are depend on?

A

The material
The temperature
The pressure

64
Q

Explain the forces of attraction (structure), shape and volume, and the movement of particles in solids?

A

In solids, there are strong forces of attraction between the particles, which holds them close together in fixed positions to form a regular lattice arrangement.

The paricles dont move from their positions, so all solids keep a definite shape and volume.

The particles vibrate in their positions- the hotter the solid the more they vibrate (causing solids to expand slightly when heated).

65
Q

Explain the forces of attraction (structure), shape and volume and movement of paritcles in liquids?

A

In liquids theres a week force of attraction between the particle. Randomly arranged and free to move past each other, but tend to stick closely together.

Liquids have definite volume but dont keep a definite shape, and will flow to fill the bottom of the container.

The particles are constantly moving with random motion. The hotter the liquid gets the faster they move. This causes liquids to expand slightly when heated.

66
Q

Explain the forces of attraction, shape and volume and movement of gases.

A

In gases, the force of attraction between the particles is very week - free to move and are far apart. The particles in gases travel in straight lines.

Gases dont keep a definite shape or volume and will always fill any container.

The particles move constantly with random motion. The hotter the object gets the faster they move. Gases either expand when heated or their pressure increases.

67
Q

Limitations of the particle theory?

A

The particles arent solid or inelastic or spheres theyre atoms ions or molecules. The model doesnt show the forces between the particles so theres no way of knowing how strong they are.

68
Q

What does the amount of energy needed for a substance to change state depend on?

A

The amount of energy needed for a substance to change state depends on how strong the forces between the particles are. The stronger the forces the more energy is needed to break them, and so higher melting and boiling points of the substance.

69
Q

Explain melting?

A

1)When a solid is heated, its particles gain more energy.
2) This makes the particles vibrate more, which weakens the forces that hold the solid together.
3) At a certain temp (melting point) particles have enough energy to break free from their positions.
This is melting and turns solids into liquids.

70
Q

Explain boiling (evaporating)?

A

4) When a liquid is heated, again the particles gain more energy.
5) This energy makes the particles move faster, which weakens and breaks the bonds holding the liquid together.
6) At a certain temp (boiling point), the paricles have enough energy to break their bonds.
This is boiling (evaporating) -liquid becomes a gas.

71
Q

Explain condensing?

A

7) As a gas cools, the particles no longer have enough energy to overcome the forces of attraction between them.
8) Bonds form between the particles.
9) At the boiling point, so many bonds have formed between the gas particles that the gas becomes a liquid (condensing).

72
Q

Explain freezing?

A

10) When a liquid cools, the particles have less energy so move around less.
11) Theres not enough energy to overcome the attraction between the particles, so more bonds form between them.
12) At the melting point, so many bonds have formed between the particles that theyre held in place. The liquid becomes a solid (freezing).

73
Q

What is the diameter of nanoparticles?

A

Between 1nm and 100nm, particles that contain only a few hundred atoms.

74
Q

What do fine particles have a diameter between?

A

100-2500nm (1 x 10^-7m ) and (2.5 x 10^-6m )

75
Q

What do coarse particles have a diameter between and what are they also called?

A

2500nm and 10,000nm (2.5 x 10^-6m ) and (1x`0^-5 m). Theyre also known as dust.

76
Q

What happens to the surface area to volume ratio when the side of the cube decreases?

A

As the side of the cube decreases by a factor of 10 the surface area to volume ratio increases by a factor of 10.

77
Q

What does nanoparticles high surface to volume ratio cause them to have?

A

Nnaoparticles may have properties different from those for the same materials in bulk and also smaller qualities are needed to be effective than for materials with normal particle sizes bc of their high surface area to volume ratio.

78
Q

What can nanoparticles be used for?

A

-Making catalysts ( bc high SA:V ratio)
-Medicine
-Electronics
-Deodrants
-Cosmetics (moisturisers without making them too oily) and suncreams

79
Q

How can nanoparticles be used in medicines?

A

Tiny particles (eg fullerenes) are absorbed more easily from the body than most particles so they can deliver drugs right in the cells where they are needed.

80
Q

How can nanoparticles be used as electronics?

A

Some nanoparticles conduct electricity so they can be used in tiny electric circuits for computer chips.

81
Q

How can nanoparticles be used as deodrants?

A

Silver nanoparticles have antibacterial properties. They can be added to polymer fibres which can then be used to make deodrants.

82
Q

Why is it important that nanoparticles are tested before use?

A

New products containing nanoparticles are tested thoroughly to minimse risks as the way they affect the body isnt fully understood and we dk the long term effects.

83
Q

Evaluate the use of nanoparticles in sun screams?

A

Used is suncreams as they have been shown to be better than normal sun creams at protecting skin from harmful UV rays and give better skin coverage.
However we dk yet if the nanoparticles can get into the body and damage cells. They may also be able to be washed away and damage the environment.

Chemistry (5 decks)

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