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Chemistry AS Level ~Sabz ❤ > Chapter 5~ States Of Matter > Flashcards

Chapter 5~ States Of Matter Flashcards

Learn definitions, formulae and key ideas💡 (comparisons of volume with pressure and temperature are made from ideal gases)

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1
Q

Gases have no fixed volume or shape. Gas particles have 3 characteristics namely :

A
  1. Are far apart, therefore gases CAN be compressed
  2. Are randomly arranged
  3. Can move freely from place to place, in all directions.
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2
Q

Liquids take the shape of the container they occur. Liquid particles have 3 characteristics namely :

A
  1. Are close together, so liquids have a fixed volume and can only be compressed slightly
  2. Are arranged fairly randomly
  3. Have limited movement from place to place, in all directions
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3
Q

Solids have a fixed shape and volume. Solid particles have 3 characteristics namely :

A
  1. Are touching each other, so solids can NOT be compressed
  2. Are usually in a regular arrangement
  3. Can NOT change positions with each other - they can only vibrate
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4
Q

The state of a substance @ room temperature and pressure depends on its? (2)

A

Structure and bonding

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5
Q

What are the 5 types of structures found in elements and compounds plus an example of each?

A
  1. Simple atomic (e.g. Argon)~all noble gases
  2. Simple molecular (e.g. Carbon dioxide)
  3. Giant ionic (e.g. Sodium chloride)
  4. Giant metallic (e.g. Iron)
  5. Giant molecular (e.g. Silicon (iv) oxide)
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6
Q

Definition of the kinetic theory of gases :

A

°The theory that particles in a gases and liquids are in constant movement. The kinetic theory can be used to explain the effect of temperature and pressure on the volume of gas as well as rates of chemical reactions.

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7
Q

The ideal gas law

The kinetic theory of gases makes 5 assumptions refered to as the IDEAL gas characteristics :

A
  1. Gas molecules move rapidly and randomly
  2. the distance between the gas molecules is much greater than the diameter of the molecules so the volume is negligible
  3. There are no forces of attraction or repulsion between the molecules
  4. All collisions 💥 between particles are elastic
  5. The temperature of the gas is related to the average kinetic energy of the molecules
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8
Q

What is meant when a collision 💥 is said to be elastic?

A

No kinetic energy is lost in collisions

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9
Q

Kinetic energy is the energy associated with?

A

Moving particles

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10
Q

Definition of ideal gases :

A

°a gas whose volume varies in proportion to the temperature and in inverse proportion to the pressure. Noble gases such as Helium and Neon approach ideal behaviour because of their low intermolecular forces

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11
Q

Definition of a real gas :

A

Gases that that do NOT obey the ideal gas law, especially at low temperatures and high pressures

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12
Q

I

The volume that a gas occupies depends on 2 things :

A
  1. its pressure (In pascals, Pa)

2. It’s temperature (in Kelvin, K)

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13
Q

Why do gases in containers exert pressure?

A

Bec the molecules are constantly hitting the walls of the container

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14
Q

If the volume is decreased the pressure will….?

A

Increase

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15
Q

If the volume is increased the pressure will….?

A

Decrease

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16
Q

Graph.

As volume increases what form of pressure increases?

A

1/p

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17
Q

As temperature increases, the volume of gas…..

A

Increases

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18
Q

Real gases do not always obey the kinetic theory in 2 way :

A
  1. there is NOT zero attraction between molecules

2. We can NOT ignore the volume of gas molecules themselves

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19
Q

An ideal gas will have a volume that that varies exactly in proportion to its

A

Temperature

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20
Q

The volume of an ideal gas varies exactly in inverse proportion to its

A

Pressure

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21
Q

There are differences between real gases and ideal gases and these differences are especially noticeable at very high pressures and very low temperatures.
Under these conditions there are 6 characteristics that prove that real gases do NOT behave like ideal gases.
Under these conditions real gases :

A
  1. Molecules are close to each other
  2. The volume of the molecules is not negligible compared with the volume of the container
  3. There are van Der Waal’s forces or dipole - dipole forces of attraction between the molecules
  4. Attractive forces pull the molecules towards each other and away from the walls of the container
  5. The pressure is lower than expected for an ideal gas
  6. The effective volume of the gas is smaller than expected for an ideal gas
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22
Q

Definition of the general gas equation :

A

°an equation relating the volume of a gas to the temperature, pressure and number of moles of a gas. It is also called the ideal gas equation :

pV=nRT

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23
Q

Formula of the ideal gas equation

Plus
The units of each individual

A

pV=nRT

p- in Pa

V- m^3

n - mol

R-gas constant 8.13JK^-1

T- in K

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24
Q

To change degrees to Kelvin

A

+273

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25
Q

To change dm^3 to m^3…

A

Divide by 1000

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26
Q

A syringe oven can be use to find the…

A

Relative molecular mass of a volatile liquid

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27
Q

The behaviour of liquids.

If we heat a solid (melt) 3 things happen :

A
  1. The energy ⛮ transferred to the solid makes the particles vibrate more vigorously
  2. The forces of attraction between the particles are weakened
  3. The solid changes to a liquid when it’s temperature is sufficiently high
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28
Q

The particles in a liquid are still close to each other but they have enough………….. *fill in * To keep sliding passed each other in a fairly random way

A

Kinetic energy

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29
Q

When we cool (freeze) a liquid, the particles do 3 things :

A
  1. Lose kinetic energy so they do not move around so readily
  2. Experience increasing forces of attraction
  3. Stop sliding past each other when the temperature is sufficiently low, the liquid solidifies.
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30
Q

The change from liquid state to gas state is?

A

Vaporisation

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31
Q

When a vapour is cooled to a liquid. The state change is called?

A

Condensation

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32
Q

Definition of vaporisation

A

°the change in state when a liquid changes to a vapour

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33
Q

When we cool a vapour (to vaporise it) 3 things take place:

A
  1. Lose kinetic energy so the molecules move around less quickly
  2. Experience increasing forces of attraction
  3. Move more slowly and become closer together when the temperature is sufficiently low; the gas liquidfies
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34
Q

Definition of condensation

A

°the change in physical state when a vapour changes to a liquid

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35
Q

As more molecules move from liquid to vapour, some begin to move back to the liquid. When is an equilibrium met?

A

When molecules going from liquid to vapour at the SAME RATE as from vapour to liquid

36
Q

Definition of vapour pressure :

A

°the pressure exerted by a vapour in equilibrium with a liquid

37
Q

Vapour pressure will increase when the temperature increases because of 2 reasons :

A
  1. the gas particles have more kinetic energy

2. the gas particles move faster, so are able to overcome intermolecular forces of attraction more easily

38
Q

Definition of boiling point :

A

° the temperature at which the vapour pressure is equal to the atmospheric pressure

39
Q

Definition of lattice :

A

°a regular repeating arrangement of ions, atoms or molecules in 3 dimensions

40
Q

In ionic lattice they have an arrangement of alternating…..?

A

Positive and negative ions

41
Q

5 of properties of ionic compounds reflecting their structure as well as their bonding :

A
  1. they=hard. Takes a lot of energy to scratch /mark the surface bec of the strong attractive forces keeping the ions together
  2. they =brittle. May split when struck in the same direction as layers of ions. The ions may be displaced by the force & ions of same charge may come together. The repulsion between these ions in the layers cause the crystal to split along these cleavage planes
  3. High MP & BP bec the attractive between the large number of oppositely charged ions acts in all directions and bonds them strongly together.

The MP & BP also increase with charge density

  1. many are soluble in water
  2. They conduct electricity when molten or in solution
42
Q

Formula for charge density

Does it increase or decrease down the group?

A

=size of atom /charge

Therefore, it decreases down a group

43
Q

Do the BP and MP increase / decrease with an increase on the charge density? Why? Plus an example

A

Increase,

Bec there is greater electrostatic attraction between ions with greater charge and smaller size (or same size)

E. G. Mg^2+; O^2- has a MUCH HIGHER BP AND MP than Na^+ and Cl^-

44
Q

Explain the property of most metallic lattices having :

High tensile strength and hardness

A

Due to strong attractive forces between metal ions and delocalised e-‘s

45
Q

What does malleable refer to?

A

Can be hammered into different shapes

46
Q

What does ductile refer to?

A

Can be drawn into wires

47
Q

Why is it so that metallic lattices allow metals to be malleable and ductile? Explain the property.

A

When a force is applied the layers can slide over each other.

In a metallic bond, the attractive forces between the metal ions and delocalised e-‘s act in all directions.

So when the layers slide, new metallic bonds are easily re-formed between ions in new lattice positions and delocalised e-‘ s

The delocalised e-‘s continue to hold the ions in the lattice together.

48
Q

Definition of an alloy :

A

°a mixture of 2 or more metals or a metal with a non-metal.

the metal added to create the alloy becomes part of the crystal lattice of the other metal

49
Q

Brass is an alloy of?

Why use alloy?

Examples where it is used

A

Copper (70%) and zinc (30%)

Stronger than just copper but still malleable.

Uses: musical instruments, ornaments and household items such as door handles

50
Q

Why are alloys stronger than pure metallic lattices?

A

Bec the presence of different - sized metal ions makes the arrangement of the lattice less regular. This stops the layers from sliding over each other so easily when a force is applied

51
Q

State 4 properties of PURE aluminum.

Explain why pure aluminum is not used in engineering.

A
  1. soft
  2. Ductile
  3. high electrical conductivity
  4. High thermal conductivity

Bec of its low strength.

52
Q

The strength of aluminum can be increased by addition of other elements such as (4)?

A

Copper

Magnesium

Silicon

Manganese

53
Q

Name 3 properties of alloys of aluminum

and 3 practical examples of where it is used

A
  1. Lightweight (low density)
  2. Strong
  3. Resistant to corrosion

Used for : bodies of aircraft, for the cylinder blocks of car engines and for bicycle frames

54
Q

Bronze is an alloy of?

A

Copper and tin

55
Q

Simple molecular lattice reflects..

A

The regular packing of molecules in a lattice structure. (have covalent bonds)

56
Q

Why does iodine have a low MP?

A

This is bec of the weak van Der Waal’s forces whereas the forces between the atoms within the molecule are strong covalent bonds.

Very little energy is needed to overcome the weak van Der Waal’s forces between the molecules so the lattice is easily broken💔

57
Q

Definition of giant molecular structure :

Plus the 3 examples of the ones we learn about in AS level

A

°structures having a 3 dimensional network of covalent bonds throughout the whole structure

Examples :

  1. graphite
  2. diamond
  3. Silicon (iv) oxide
58
Q

Why do giant molecular structures have high BP & MP?

A

Bec of the large number of strong covalent bonds linking the whole structure

59
Q

Definition of allotropes plus and example :

A

Different crystalline or molecular forms of the same element. Graphite and diamond 🔹 are allotropes of carbon

60
Q

Describe the structure of graphite. 4 points

A

¬carbon atoms are arranged in planar layers. Within layers, the carbon atoms are arranged in hexagons

¬each C - atom is joint to 3 other C-atoms by covalent bonds. The 4th e- of each Carbon atom occupies a p-orbital

¬the p-orbitals on every C-atom in each planar layer overlap sideways. A cloud of delocalised e-‘s is formed above and below the plane of Carbon rings. These e- clouds join to form extended delocalised rings of e-‘ s

¬layers of C-atom are held by weak van Der Waal’s forces

61
Q

What are the 3 properties of graphite that are related to its structure?

A
  1. High MP & BP : there are strong covalent bonds throughout the layers of C-atoms. A lot of energy is needed to overcome these strong bonds
  2. Softness : graphite =easily scratched. The forces between the layers of C-atoms are weak. The layers can slide over each other when force is applied, and readily flake off.
  3. Good conductor of electricity : when a voltage ⚡ is applied, the delocalised (mobile) e-‘s can move along the layers
62
Q

Why is graphite used in pencil ‘leads’? 2

A

It’s ‘flakiness’, it is slippery and soft

63
Q

Describe the structure of diamond 🔹 : (3)

A

¬ each C-atom has 4 covalent bonds with other C-atoms.

¬ the C-atoms are tetrahedrally arranged around each other

¬the regular arrangement of atoms gives diamond 🔹 a crystalline structure

64
Q

The 3 properties of diamond 🔹 that are related to its structure are?

A
  1. High MP & BP : due to strong covalent bonding throughout the structure. A lot of energy is required to break these strong bonds
  2. Hardness: 🔹 can NOT be scratched easily bec it’s difficult to break the 3-D network of strong covalent bonds
  3. Does NOT conduct electricity / heat 🔥 : each of the 4 outer e-‘s on every C-atom is involved in covalent bonding. This means no free e-‘ s available to carry the electric current
65
Q

Sand is larger made up of…

A

Silicon (iv) oxide

66
Q

Describe the structure of silicon (iv) oxide : (2)

A

¬similar to diamond

¬ each silicon atom is bonded to 4 oxygen atoms. But each Oxygen atom is bonded to only 2 silicon atoms so the formula is SiO2

67
Q

4 of silicon dioxide’s properties : (similar to 🔹)

A
  1. It’s hard
  2. Colourless crystal
  3. High MP & BP
  4. Does NOT conduct electricity
68
Q

What are carbon nanoparticles? Plus the ones we discuss in AS level

A

Nanos called particles.
Individual particles that dimensions between a certain number of nanometers (10^-9)

  1. Fullerenes (buckminsterfullerene and nanotubes)
  2. Graphene
69
Q

What are fullerenes?

A

Allotropes of carbon in the form of hollow tubes or spheres.

70
Q

Definition of buckminsterfullerene :

A

C 60 molecule having a the 60 carbon atoms arranged in a polyhedron resembling a geodesic sphere (soccer ball⚽)

71
Q

5 Properties of a buckminsterfullerene :

A
  1. Low sublimation point: bec of weak van Der Waal’s forces between each buckminsterfullerene molecule and no continuous layered structure (as in graphite)
  2. Relatively soft : bec it does not require a lot of energy to over come the weak van Der Waal’s forces
  3. Poor conductor of electricity bec the extent of e- delocalisation is low
  4. Slightly soluble in solvents such as carbon disulphide and methylbenzene
  5. More reactive than graphite / diamond. This is bec it has a high e- density in certain parts of the molecule
72
Q

Buckminsterfullerene reacts with 5 elements :

A
  1. Hydrogen
  2. Fluorine
  3. chlorine
  4. Bromine
  5. Oxygen
73
Q

Definition of nanotubes :

A

They are fullerenes of hexagonally arranged C-atoms (like a single layer of graphite bent) to form a cylinder.

74
Q

Nanotubes have 3 characteristic properties :

A
  1. High electrical conductivity along the long axis of the cylinder : bec some e-‘s are delocalised & able to move along the cylinder when voltage ⚡ is applied
  2. High tensile strength when force is applied along the axis of the cylinder bec:
    1. Interlocking carbon- to- carbon covalent bonding
    2. It is one large molecule with no weaker areas within its structure

3.high MP bec : strong covalent bonding throughout structure

75
Q

One use of buckminsterfullerenes :

A

Small molecules can be trapped in the cage of buckminsterfullerene. Therefore, possible medical uses include delivering drugs to specific places in the body

76
Q

3 uses of nanotubes :

A
  1. Used in tiny circuits as ‘wires’ and as electrodes in paper-thin batteries
  2. Can be incorporated into clothing and sports equipment for added strength
  3. Used in the treatment of certain types of cancer ♋
77
Q

Definition of graphene

A

It is a single isolated layer of graphite. The hexagonally arranged sheet of Carbon atoms is not completely rigid and it can be distorted

78
Q

Graphene has 3 properties, similar to graphite but just more exaggerated :

A
  1. Graphene is most chemically reactive form of carbon. Single sheets of graphene burn at very low temperatures & are much more reactive than graphite
  2. Extremely strong for its mass
  3. For a given amount of material, graphene conducts electricity & heat 🔥 much better than graphite
79
Q

The 5 uses of graphene :

A
  1. Used in tiny electrical circuits
  2. Tiny transistors
  3. Tiny touchscreens
  4. Solar cells.
  5. And other energy storage devices
80
Q

2 reasons why to conserve materials?

A
  1. Limited supply of metal ores in Earth 🌎
  2. Extracting metals from their ores requires a lot of energy. Energy resources are also limited and we conserve these as well.
81
Q

What is one way to conserve metals?

A

Recycling metals

82
Q

The 4 advantages of recycling ♻ metals

A
  1. Saves energy ⛮ (we 🔥 less fossil ⛽ so less global warming)
  2. It conserves supplies of the ore
  3. landfills do not get filled up as fast and there is less waste 🗑
  4. It is cheaper than extracting the metal from its ore
83
Q

Two metals easily recycled are

A

Copper and aluminum

84
Q

Recycling ♻ copper is important for 2 reasons :

A
  1. Less energy is required to recycle copper than is needed to transport copper ore to the smelting plant & extract copper from it
  2. Less energy is required to extract and refine the recycled copper so that it is pure enough to be electrolysed
85
Q

The 3 uses of copper

A
  1. Water pipes(doesn’t have to be pure)
  2. Cooking utensils (doesn’t have to be pure)
  3. Electrical wiring (has to be pure)
86
Q

Purifying and remoulding ALUMINUM is much cheaper than extracting aluminum from bauxite ore.

Savings are made for 4 reasons:

A
  1. Not necessary to extract the Al ore from the ground or to transport it to smelting plants ; these processes require energy
  2. Treatment of bauxite to make pure Al oxide for electrolysis does not need to be carried ouf
  3. Al scrap needs less energy ⛮ to melt it, compared with melting Al oxide
  4. Expensive electrolysis of Al oxide does not have to be carried out

95% saving in energy ⛮ if Al is recycled instead of extracted from its ore

Chemistry AS Level ~Sabz ❤ (7 decks)

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