⚛ Chemistry Paper 1 Flashcards

1
Q

Chem: what is the equation for atom economy

A
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2
Q

Chem: what type of atoms are used in and what happens in covalent bonding

A

2 or more non-metals, sharing electrons

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3
Q

Chem: what happens in metallic bonding and in what type of atoms

A

Positive metal ions in a sea of delocalised negative electrons, in metals

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4
Q

Chem: what happens in ionic bonding and in what type of atoms

A

Gives/takes electrons, metals and non-metals

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5
Q

Chem: what is a activation energy

A

The minimum energy required to start a chemical reaction

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6
Q

Chem: what is an energy profile

A

A graph showing energy change during a chemical reaction

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7
Q

Chem: what is an exothermic reaction

A

A chemical reaction that releases energy

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8
Q

Chem: what is an endothermic chemical reaction

A

A chemical reaction that takes in energy

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9
Q

Chem: what happens in a chemical reaction

A

Bonds are broken and formed and atoms are rearranged

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10
Q

Chem: how thick is one nm in terms of atoms

A

10 atoms thick

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11
Q

Chem: order in terms of size, from smallest to largest, coarse particles, nano particles and fine particles

A

Smallest - largest: nanoparticles, fine particles, coarse particles

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12
Q

Chem: what is the size of coarse particles

A

2500 to 10000 nm

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13
Q

Chem: what is the size of fine particles

A

100 to 2500 nm

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14
Q

Chem: what is the size of nano particles

A

1 to 100 nm thick

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15
Q

Chem: is the anode the positive or negative electrode in electrolysis

A

Positive

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16
Q

Chem: is the cathode positive or negative in electrolysis

A

Negative

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17
Q

Chem: is an anion positive or negative

A

Negative

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18
Q

Chem: is a cation positive or negative

A

Positive

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19
Q

Chem: what happenes at the negative electrode in electrolysis of aqueous solutions

A

Hydrogen atom forms , only if the metal is more reactive than it
Also electrons transferred to ion to make it an atom

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20
Q

Chem: is electrolysis of aqueous solutions what happens at the positive electrode

A

Oxygen produced, unless a halogen present then the halogen is produced
Electron transferred from ion to positive electrode

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21
Q

Chem: what is an aqueous solution

A

Something dissolved in water

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22
Q

Chem: what is the definition of electrolysis

A

Electrolysis is the process of splitting ionic compounds using electric current

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23
Q

Chem: how do you work out moles of an atom

A

Moles= mass / formula mass

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24
Q

Chem: how do you work out the formula mass (Mr) of a molecule

A

It is the sum of the elements in the molecule

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25
Q

Chem: work out the Mr of K ₂O if the formula mass of of K is 39 and O is 16

A

39+39+16=94

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26
Q

Chem: How do you write ionic equations

A

Split the equation so
- NaOH ( aq ) + HNO 3 ( aq ) → NaNO 3 ( aq ) + H 2 O ( l ) would become
- Na + OH ( aq ) + H + NO 3 ( aq ) → Na + NO 3 ( aq ) + H 2 + O ( l )
- Then cross out the portions that do not change their charge, this becomes
- OH ( aq ) + H → H 2 O ( l )

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27
Q

Chem: what is an ionic equation

A

It is a chemical equation with all of the things that do not change charge removed

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28
Q

Chem: what is oxidation

A

Oxidation is the loss of electrons and the gain of oxygen

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29
Q

Chem: what is reduction

A

It is the gain of electrons and possibly gain of hydrogen and the loss of oxygen

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30
Q

Chem: in electrolysis does reduction or oxidation occur at the positive electrode

A

Oxidation

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31
Q

Chem: in electrolysis does oxidation or reduction occur at the negative electrode

A

Reduction

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32
Q

Chem: what is a half equation

A

Electrons are represented, they are 2 equations that show how electrons are transferred at each electrode in electrolysis

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33
Q

Chem: what is the equation for complete combustion

A

Hydrocarbon + oxygen -> carbon doxide + water

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34
Q

Chem: what is the equation for incomplete combustion

A

Hydrocarbon + oxygen -> carbon doxide + water + carbon monoxide

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35
Q

Chem: what is the definition of carbon footprint

A

this is the total amount of carbon dioxide and other greenhouse gases that are emitted over the full lifecycle of a product, service or event

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36
Q

Chem: what is carbon footprint offsetting

A

Say you buy a plane ticket, planting trees to offset the greenhouse gasses released by the journey

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37
Q

Chem: what is the order of events for the formation of life

A

Volcanoes, oceans, algiae, plants, animals

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38
Q

Chem: what are the percentages of gasses in the atmosphere

A

Nitrogen-78, oxygen-21, other gasses-1

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39
Q

Chem: what are the 4 alkanes you need to remember

A

Methane, ethane, propane, butane

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40
Q

Chem: what is crude oil made of

A

Fossilised plankton that was buried in mud

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41
Q

Chem: what is the definition of a mixture

A

A substance composed of 2 or more differeent compounds or elements not chemically bonded

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42
Q

Chem: what is ionic bonding and in what types of elements does it occur

A

Giving/taking electrons
Between metals and non metals

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43
Q

Chem: what is covalent bonding and in what type of elements does it occur

A

Sharing electrons
2 non metals

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44
Q

Chem: what is metallic bonding and in what type of elements does it occur

A

Sea of delocalised electrons
Metals

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45
Q

Chem: what are the properties of covalently bonded substances

A
  • Non-conductive(no charged particles that can carry a charge)
  • low melting point
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46
Q

Chem: what are the properties of ionically bonded substances

A
  • Conduct when dissolved in water
  • hard and brittle
  • high melting and boiling points.
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47
Q

Chem: what defines potable water

A

It is safe to drink, it should have low levels of dissolved salts and of microbes.

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48
Q

Chem: what are the 2 ways of getting potable water from salt water

A

Distillation , reverse osmosis

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49
Q

Chem: what is reverse osmosis

A

It is osmosis where the water moves from low to high concentration because of large amounts of pressure

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50
Q

Chem: what is distillation

A

Where a liquid is evaporated and collected from a mixture

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51
Q

Chem: what are the 3 ways water is steralized

A

UV, chlorine, ozone

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52
Q

Chem: what is pure water

A

Water that is not in a mixture

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53
Q

Chem: how many cm3 in a dm3

A

1000

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54
Q

Chem: how do catalysts work

A

They change the reaction pathway

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55
Q

Chem: what are the 5 factors that affect rate of reaction

A
  • temp
  • concentration
  • catalyst
  • pressure
  • surface area
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56
Q

Chem/bio: how do enzymes make things react

A

They lower the activation energy

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57
Q

Chem: what is a the difference between weak and strong acids

A

Weak acids have low amounts of ionised hydrogen ions, whereas in strong acids there is a large amount of ionised hydrogen ions

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58
Q

chem: what is a mole

A

1 mol is the unit for amount of substance, its the 6.02 x10^23 atoms

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59
Q

chem: what is percentage yield

A

actual yield / theoretical yield x 100

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60
Q

chem: what is the equation for relative formula mass

A

adding up all of the relative atomic masses of the atoms in a formula

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61
Q

Chem: what is the difference in amount of hydrogen ions between PH 2 and PH 1

A

10x, each jump is a gap of 10x as it is a logarithmic scale

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62
Q

Chem: what hydrogen ions constitute acids, are they positive or negative

A

H+ ions

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63
Q

Chem: what hydrogen ions constitute alkalise, what charge are they

A

OH- ions

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64
Q

chem: in electrolysis does reduction happen at the cathode or anode

A

cathode

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65
Q

chem: in electrolysis does oxidation happen at the cathode or anode

A

anode

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66
Q

Chem: what is the difference between giant and simple covalent bonding

A
  • Simple covalent - fixed number of atoms in the structure
  • giant covalent - undefined amount of atoms.
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67
Q

Chem: why do simple covalent compounds have low melting and boiling points

A

The have weak intermolecular forces, this means less energy is needed to overcome these forces

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68
Q

Chem: what is the difference between atomic and intermolecular forces

A

Atomic forces are forces within an atom and intermolecular forces are the forces between atoms.

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69
Q

Chem: what are the properties of simple covalent compounds

A

Low melting and boiling point, do not conduct

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70
Q

Chem: what are the properties of giant covalent

A

High melting and boiling point.

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71
Q

Chem: what are the properties of ionic compounds

A
  • High melting and boiling points
  • when molten or dissolved the conduct
  • when solid the have poor conductivity
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72
Q

Chem: what are the properties of metallic bonding

A

Conductivity

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73
Q

Chem: define concentration

A

Amount of particles in a given volume

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74
Q

Chem: to increase the rate of reaction for an Exothermic reaction by changing temp what do you do, cool or heat? Why?

A

Cool, if there is less energy in the surroundings it is easier for the reaction to give out energy.

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75
Q

Chem: what is a solvent

A

A liquid in which a solid dissolves

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76
Q

Chem: what is a solute

A

Dissolved solid

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77
Q

Chem: what is a solution

A

A liquid which contains a dissolved solid

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78
Q

Chem: what are the 5 ways of separating mixtures

A
  • crystallisation
  • filtration
  • chromatography
  • simple distillation
  • fractional distilation
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79
Q

Chem: explain fractional distillation

A

A mixture of several substances is separated by distilling the mixture and then evaporating and collecting the individual components using their individual boiling points

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80
Q

Chem: define distillation

A

Purifying a liquid by heating and cooling

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81
Q

Chem: explain simple distillation

A

It separates 2 liquids with different boiling points, the mixture with the lower boiling point is boiled off and collected

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82
Q

Chem: explain crystalization

A

To separate a soluble substance from a solvent, evaporate the solvent to form crystals of the solute

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83
Q

Chem: explain filtration

A

Used to separate an insoluble solid from a liquid, the mixture is put through a filtration device to collect the liquid and the solid/s

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84
Q

Chem: explain chromatography

A

Used to separate mixtures of soluble substances in a solution, paper chromatography this works on the principle that some substances are more soluble

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85
Q

Chem: what is the equation of concentration (used in titrations)

A

Concentration = moles / volume

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86
Q

Chem: define decomposition

A

The process of breaking down

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87
Q

Chem: what is thermal decomposition

A

A compound that breaks down when heated

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88
Q

Chem: what are the 2 catalysts used in catalytic converters

A

Palladium and platinum

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89
Q

chem: what are the properties of the transition metals

A
  • they have high melting and boiling points
  • higher dencity
  • lower reactivity
  • greater strength and hardness
  • some of them can be used as catalysts
  • form coloured compounds
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90
Q

chem: what is an acid

A

it is a substance that forms H+ ions when dissolved in water

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91
Q

chem: what is an alkali

A

it is a substance that forms OH- ions when dissolved in water

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92
Q

chem: when reacting with other substances what charged ions do metal atoms form

A

posotive

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93
Q

chem: what is the reactivity of a metal baced on

A

its ability to form its posotive ion

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94
Q

chem: what is an ion

A

it is an atom or group of them that has any charge

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95
Q

chem: what is a spectator ion

A

it is an ion that, in a reaction does not change its charge

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96
Q

chem: what is the difference between an alkali and a base

A

a bace is an alkali that is not soluable in water

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97
Q

chem: when lithium reacts with water what happens

A

fizzes steadily and floats

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98
Q

chem: when potassium reacts with water what happens

A

reacts quickly, hydrogen produced is instantly ignited and the metal ignites too, buring with a lilack flame

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99
Q

chem: when sodium reacts with water what happens

A

fizzes rapidly and melts, moves around on the waters surface

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100
Q

chem: why and how are metals less reactive than carbon extracted from their ore by carbon

A

the metal is reduced (looses its oxygen). carbon (in the form of coal) is used because it is cheap and abundent

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101
Q

chem: when acids react with metals what is formed

A

hydrogen and a salt

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102
Q

chem: what are the 3
types of base that acids can be neutralised with

A
  • metal carbonates
  • metal oxides
  • metal hydroxides
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103
Q

chem: acid + metal oxide ->

A

salt + water

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104
Q

chem: acid + metal hydroxide ->

A

salt + water

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105
Q

chem: acid + metal carbonate ->

A

salt + water + carbon dioxide

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106
Q

chem: what are the 3 ways of detecting the acidity or alkalinity of a substance

A
  • litmus paper
  • universal indicator
  • PH probe
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107
Q

chem: what litmus paper is used to determine alkalinity

A

red litmus paper turns blue

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108
Q

chem: what litmus paper is used to determine if a substance is acidic

A

blue litmus paper turns red

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109
Q

chem: define titration

A

it is a technique that measures the volumes of acid and alkali solutions needed in a neutralization reaction

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110
Q

chem: define a strong acid

A

it is an acid that when in water fully ionises, all of the acid breaks up to form H+ ions

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111
Q

chem: what is a weak acid

A

it is an acid that when in water does not fully ionise, most are weak

112
Q

chem: what is the equation for fermentation (yeast)

A

glucse -> ethanol + carbon dioxide

113
Q

chem: what is a limiting reactant and how do you find it

A

it is the reactant that is completely used up first, the reaction stops when this happens, you find it by finding the reactant with the lowest moles

114
Q

chem: if i fill 3 ballons with gas, one with 1 mole methane, one with 1 mole argon and one with 1 mole chlorine, which baloon will be the largest

A

they will all be the same size because at the same temperature and pressure one mole of any gas will have the same volume because it is the same amount of atoms.

115
Q

chem: for titrations what is the range for concordant results

116
Q

chem: if a there is 20 cm3 of liquid in my measuring tube and it has an uncertanty of 1 cm3, write lower and upper bounds for the amount of liquid

A

19.5 < l < 20.5

117
Q

chem: Name three factors that make the percentage yield of a reaction less than 100%?

A

reaction is incomplete
waste products
side reactions

118
Q

chem: what makes a chemical cell have more voltage/potential difference

A

more difference in reactivity will result in more voltage

119
Q

chem: what happens to a chemical cell when you change the electrode

A

changing the electrode will change the reactions that happen at each electrode and so change the voltage

120
Q

chem: what makes a chemical cell non - rechargable

A

irreversable chemical reactions take place at the elctrodes, as soon as the one of the reactants has run out electrisity cannot be produced.

121
Q

chem: what makes a chemical cell rechargable

A

connection to an electric current reverses the reactions that occured to produce electrisity and recharges the cell

122
Q

chem: what are fuel cells

A

they produce electrical energy by reacting a fuel (often hydrogen) with oxygen (e.g. from the air), when this happens a current is produced and a current will continue to be produced unitll the fuel runs out.

123
Q

chem: what are the pros of fuel cells

A
  • they have high efficiency
  • they can produce less polution
  • they are reliable as they have no moving parts
  • they can be compact
124
Q

chem: hydrogen fuel cells vs petrol, which has a higher energy per gram

A

hydrogen fuel cells

125
Q

Chem: if a change of state happens and the temperature increases during the change of state what can we say about the substance

A

It is impure or a mixture

126
Q

Chem: what is Rf in chromatography

A

It is the retention factor, its equation is distance traveled by dye(compound) / distance traveled by solvent

127
Q

Chem: what is chromatography used for

A

It is used to distinguish between pure and impure substances

128
Q

chem: why are small covalent molecules liquids or gasses at room temperature

A
  • when molecules melt or boil it is the intermolecular forces that break
  • these intermolecular forces are weak in simple covalent substances
129
Q

chem: define alloys

A

they are combinations of 2 or more elements when one of them is a metal

130
Q

chem: what is the difference between metals and alloys (in properties)

A

alloys are:
- stronger than metals
- contain other elements
- harder
- the layers in alloys are distorted

131
Q

chem: what are the 2 types of conducter

A
  • heat - delocalized electrons can carry heat
  • electrical
132
Q

chem: what is an allotrope and what is an example of one

A
  • it is a different form or an element
  • diamond is an allotrope of carbon
133
Q

chem: what are the properties of diamond

A
  • they are hard, they have lots of covalent bonds
  • covalent bonds, every carbon atom is bonded to 4 others
  • diamond has not delocalized electrons that can conduct a charge
  • high melting and boiling point, it is very hard to break strong covalent bonds, hence high melting and boiling point
134
Q

chem: what are the properties of graphite

A
  • covalent bonds, each carbon atom is bonded to 3 others
  • soft, there are layers to graphene that are able to slide over one another
  • conductivity, each carbon atom forms 3 bonds, there is a delocalized electron for every carbon atom
135
Q

chem: what are the properties of graphene

A
  • conducts, delocalized electron can conduct
  • graphene is light but strong because it is one layer thick
136
Q

chem: what is a fullerine

A

they are allotropes of carbon that take hollow structures

137
Q

chem: what is the first spherical fullerene called

A

it is called buckminsterfullerene (C60)

138
Q

chem: what are some uses of buckminsterfullerenes

A
  • catalysts
  • lubricants
  • as vehicles for transporting drugs into our bodies
139
Q

chem: what are some properties of cylindrical fullerenes

A
  • strength, strong covalent bonds
  • conductivity
140
Q

chem: describe cylindrical fullerenes

A

they are called carbon nanotubes and take the shape of a cylinder, they are often called molecular wires because they have a tiny diameter but are very long

141
Q

chem: what are some uses of cylindrical fullerenes

A
  • electronics
  • nanotechnology
  • for strengthening materials
142
Q

chem: what are clumps of particles

A

matter often ‘clump’ up into small particles, the size of the clump gives it a different name:
- nanoparticles
- fine particles
- coarse particles

143
Q

Chem: why, when tennessine was discovered in 2010, was it not recognised as a new element until 2015

A

Because the discovery of the element must be repruducable

144
Q

Chem. what is the dependent variable

A

The one that the depends on the other variables

145
Q

Chem: how to calculate overall energy change

A

Energy in bonds of reactants - energy in the bonds of products = overall energy change
Energy in - energy out = overall energy change

146
Q

Chem: why do alloys conduct electricity worse than pure metals

A

Because the different elements in the alloy interrupt the lattice structure and make it harder for the electrons to move through the structure

147
Q

Chem: what equation links moles, volume and concentration

A

Conc = moles / volume

148
Q

Chem: explain how aluminium conducts electricity in terms of electrons

A
  • delocalised electrons
  • they can carry a charge
  • they flow through the substance
149
Q

chem: who came up with the plum pudding model, when?

A

JJ thompson, 1897

150
Q

chem: who thought the atom was a nucleus with all of the posotive charge in the center and a cloud of neagtive charge, when

A

Ernest Rutherford, 1909

151
Q

chem: who came up with the idea that electrons were in shells with orbits, when?

A

Niels Bohr, 1913

152
Q

chem: who came up with the idea of protons, when

A

Rutherford, 1919

153
Q

chem: who came up with the idea of neutrons

A

James Chadwick, 1932

154
Q

chem: what are all of the transition elements

A

they are metals

155
Q

chem: what are the properties of the alkali metals

A
  • low dencity
  • relativly low melting point
  • soft, can be cut with a scalpel
  • very reactive
156
Q

chem: what is a giant ionic latice

A

it is an ionic structure with an underined amount of ions

157
Q

chem: what are the properties of giant ionic lattices

A
  • each positive ion is surrounded by a negative ion
  • they are 3d structures
  • very strong forces of attraction between pos and neg ions (electrostatic forces of attraction) which hold the ions in place
  • very high melting and boiling points
158
Q

chem: what are electrostatic forces

A

they are the forces between posotive and negative ions

159
Q

chem: what can ionic compounds do when molten or dissolved, how?

A

they can conduct electrisity, remember that it is the ions that move not the electrons

160
Q

Chem: in diamond, graphite and graphene what are the bonds

161
Q

chem: what is the main property of nanoparticles

A

very high surface area to volume ratio

162
Q

chem: what is the empirical formula

A

The empirical formula of a compound is the simplest, whole number ratio of atoms of each element in a compound,

163
Q

chem: what is an exothermic reaction profile

164
Q

chem: what is an endothermic reaction profile

165
Q

chem: what is the structure of a hydrogen fuel cell

166
Q

chem: what type of equation shows electrons

A

Half equations

167
Q

chem: what is the reactivity series

168
Q

chem: what is the equation for moles involving Mr

A

Moles = mass / Mr

169
Q

Chem: what are 4 types of Exothermic reactions

A
  • neutralisation
  • combustion
  • oxidation
  • hand warmer
170
Q

Chem: what are the 3 types of endothermic reactions

A
  • thermal decomposition
  • citric acid + sodium hydrocarbonate
  • sport injury packs
171
Q

Chem: what are the 2 requirements for a reaction to occur

A
  • collisions
  • activation energy
172
Q

Chem: through bond energy how do you find if a reaction is Exothermic or endothermic

A

You can subtract the bond energy from products and reactants, if the answer is pos then it is endothermic and if the answer is negative then it is Exothermic

173
Q

Chem: how many electrodes are required to create a chemical cell

174
Q

Chem: what is a battery

A

It is multiple cells joined in series

175
Q

Chem: what are the 2 parts of chemical cells

A

Electrodes and electrolytes

176
Q

Chem: how do you find the voltage of a battery

A

It is the sum of the voltages of the individual cells

177
Q

Chem: what is the reason for a battery not being usable any more

A

Chemicals in the battery running out

178
Q

Chem: what happens to the boiling point of water when it is impure

A

It is nit 100 degrees and will boil over a range of possible temperatures based on how impure and what the impurities are

179
Q

Chem: what is limewater an aqueous solution of

A

Calcium hydroxide

180
Q

Chem: what type of compounds do transition metals form

181
Q

Chem: where do delocalised electrons in metals come from

A

The outer shell, bonding of metals remember and put in answer

182
Q

Chem: what type of bonds in metals give them high melting points

A

Strong metallic bonds

183
Q

Chem: what are metallic bonds

A

They are the bonds between the ions and the delocalised electrons

184
Q

Chem: why are pure metals soft and malliable

A

Because they have layers that can slide over one another

185
Q

Chem: why are alloys harder than pure metals

A

Because the other elements in the structure interrupt it and impeded the layers from sliding over one annother

186
Q

Chem: what is the method by which titrations are performed

A

In a titration one solution of a known concentration is added slowly to another solution with a know volume but unknown concentration, in order to find it

187
Q

Chem: what is the table you use to perform titration calculations

188
Q

Chem: what is the equation used by titrations using moles and volume

189
Q

Chem: what can acids be neutralised by

A

Alkalies, (soluable baces)

190
Q

Chem: what are some examples of exothermic reactions

A
  • neutralisation
  • combustion
  • oxidation
  • hand warmers
191
Q

Chem: what are some examples of endothermic reactions

A
  • thermal decomposition
  • citric acid + baking soda
  • sport injury packs
192
Q

Chem: what is required for simple electrical cells

A

2 electrodes

193
Q

Chem: what is the stationary phase in paper chromatography

194
Q

chem: what are coarse particles often referred to as

195
Q

Chem: what conclusions did the alpha scattering experiment disocver

A
  • the mass of an atom was concentrated in the centre of the atom
  • the nucleus was charged
196
Q

Chem: how was the nucleus discovered

A

The alpha particle scattering experiment

197
Q

chem: what was the nuclear model of the atom and what did it introduce

A

Electrons orbit the nucleus in energy levels (specific distances)

200
Q

chem: what is the approximate radius of the atom

201
Q

Chem: what is the radius of the nucleus of the atom

A

The radius of the nucleus is less than 1/10000 of that of the atom (0.1 nm)

202
Q

Chem: where is almost all of the mass of the atom

A

The nucleus

203
Q

Chem: what is group 0

A

They are the noble gasses

204
Q

Chem: what are the properties of group 0 (noble gasses)

A

They are unreactive as they have a full outer shell of electrons (8 electrons in the outer shell of all but the 2 in helium) and are also gasses, the boiling points of the noble gasses increase with increasing size (Mr)

205
Q

Chem: how can a halogen be replaced in its salt

A

A more reactive halogen can replace a less reactive one from an aqueous solution of its salt (consider how to add another flashcard)

207
Q

Chem: what are the properties of group 7, going down the group

A
  • down the group higher melting and boiling point
  • reactivity decreases
208
Q

Chem: what are the 2 types of covalent bonding and what is an example of each

A
  • simple covalent - oxygen
  • giant covalent - diamond
209
Q

Chem: what does a dot and cross diagram for ammonia look like

210
Q

chem: what are the limitations of dot and cross and ball and stick diagrams

A

They fail the illustrate the 3D arrangement of atoms and their electrons orbits

211
Q

Chem: what are the limitations of 3d models of ionic compounds

A

It is not to scale and gives no indication of the forces or transfer of electrons

212
Q

Chem: what are some limitations of a 2d representation of ionic bonding

A

It only represents one layer of the structure

213
Q

Chem: what are the limitations of these models of states of matter

A

It does not show the forces and all of the particles are represented as spheres

214
Q

Chem: why do ionic compounds conduct when they are molten or dissolved

A

Because the ions are free to move

215
Q

Chem: why are metals malliable

A

Because they are in layers that allow them to be bent and shaped

216
Q

Chem: why are metals made into alloys

A

Alloys are much harder

217
Q

chem: in diamond how many bonds do each carbon atom form and what properties does this give the structure

A
  • 4
  • increased melting and boiling point (I think adi check and remove when done so)
218
Q

Chem: in graphene how many bonds do each carbon atom form and what structure do they take and what properties does this give the structure

A
  • 3, they form hexagonal rings, there are no bonds between the layers
  • conductivity
219
Q

Chem: why is graphene similar to metals

A

Because it has delocalised electrons (they can carry a charge)

220
Q

Chem: what do graphenes properties make it useful for

A

Composites and electronics

221
Q

Chem: what is the mass of one mole of any substance equal to

A

It is numerically equal to its relative formula mass

223
Q

Chem: what is Avogadro’s constant

A

It is 6.02 X10^23 and is the number of atoms in a mole

224
Q

Chem: what is the volume of 1 mol of any gas at room temperature and pressure (20 degrees and 1 atmos)

225
Q

Chem: what is room temperature and pressure

A
  • 20 degrees
  • 1 atmosphere
226
Q

Chem: what happens to some metals when they react with acids

A

They produce salts and hydrogen

227
Q

Chem: what are redox reactions

A

It is a reaction where reduction and oxidation occur, displacement is one example, some of the atoms loose electrons and some gain them

228
Q

Chem: what is the range for the PH scale

229
Q

Chem: what are some examples of strong acids

A
  • hydrochloric acid
  • nitric acid
  • sulfuric acid
230
Q

Chem: what are some examples of weak acids

A
  • ethanoic acid
  • citric acid
  • carbonic acids
231
Q

Chem: what is the overall energy change of a reaction

A

It is the difference between the sum of the energy needed to break the bonds in the reactants and the sum of the energy released when bonds in the products are formed

232
Q

Chem: what is an exothermic reaction in terms of the overall energy change

A

The energy released from forming new bonds is greater than the activation energy (energy required to break the bonds in the reactants)

233
Q

Chem: what is an exothermic reaction in terms of the overall energy change

A

The energy released from forming new bonds is less than the activation energy (energy required to break the bonds in the reactants)

234
Q

Chem: what 2 factors affect the voltage of a chemical cell

A

Electrodes and electrolytes

235
Q

Chem: what is a simple way of making a chemical cell

A

Connecting 2 different metals in contact with an electrolyte

236
Q

Chem: what type of chemical creates non rechargeable batteries

A

Alkaline batteries

237
Q

Chem: what does connecting cells in series accomplish

A

Increasing the voltage of the battery

238
Q

Chem: how are re-usable cells recharged

A

They are recharged when an external current is supplied

239
Q

Chem: how can soluble salts be made form acids

A

They can be made from acids by reacting them with insoluble substances such as metals, metal oxides, hydroxides or carbonates, the solid is added until no more acid reacts and then the excess solid is filtered off to produce a solution of the salt

240
Q

Chem: how can soluble salts solutions be made into solid salts

A

They can be crystallized

241
Q

Chem: what happens when some acids react with metals

A

Salts and hydrogen are produced

243
Q

Chem: what is an element that reacts to form a positive ion

244
Q

Chem: what is an element that does not react to form a positive ion

A

A non-metal

245
Q

Chem: how were elements arranged before protons neutrons and electrons were discovered

A

Scientists arranged elements by their weights

246
Q

Chem: what did Mendeleev do to the periodic table that made it better

A

He left spaces for elements he thought had not yet been discovered, he also changed the order of some elements, so they were not ordered by atomic weights, elements with the properties that Mendeleev predicted filled the gaps and knowledge of isotopes explained why atomic weights were not always correct.

247
Q

Chem: what is the relative atomic mass

A

It is an average value that takes into account the abundance of each isotope of the elements

248
Q

Chem: what is the mass of an electron

A

It is very small

249
Q

Chem: what are the elements in group 0 of the periodic table called

A

The noble gasses

250
Q

Chem: what are the properties of the noble gasses

A
  • they are unreactive as they have a full outer shell, eight for all but helium which has 2
  • with growing atomic mass, going down the group, the boiling points of the gasses increase
251
Q

Chem: what are the properties of small molecules

A
  • relatively low melting and boiling points
  • do not conduct as they have no overall charge
  • when they melt and boil it is not the covalent bonds but the intermolecular forces that are overcome
252
Q

Chem: what is the shape fullerenes are baced upon

A

Hexagonal rings of carbon atoms, but they can also have rings with 5 or 7 carbon atoms

253
Q

Chem: when the side of a cube decreases by a factor of 10 what happens to the surface area to volume ratio

A

It increases by a factor of 10

254
Q

Chem: what are spherical fullerenes also known as

A

buckyballs

255
Q

Chem: why can nanoparticles have different properties to those of the same material

A

Because of their high surface area to volume ratio, they might be more useful as less of them might be needed to be as effective as less “nano” particles of the same type

256
Q

Chem: what can nanoparticles be used for

A
  • drug delivery
  • sun creams
  • antimicrobial coatings
  • catalysts
257
Q

Chem:

258
Q

Chem: what type of metals are found in teh earth not as an ore

A

Un reactive ones like gold

259
Q

Chem: what happens in a neutralisation reaction

A

Hydrogen ions react with hydroxide ions to produce water

260
Q

Chem: make card off vclCukating limiting reactants

261
Q

Chem: when drawing a diagram of electrolysis what must you remember to draw

A
  • battery, circuit
  • electrodes
  • electrolyte
262
Q

Chem: what is the reactivity series you have to remember

263
Q

Chem: what is an electrolyte

A

When an ionic compound is melted or is dissolved in water the ions are free to move within the liquid or solution, these liquids can conduct and are called electrolytes

264
Q

Chem: what happens when an electric current is passed through an electrolyte

A
  • the ions are free to move to the electrodes
  • pos ions move to the negative electrode and vice versa
  • ions are discharged at the electrodes and become elements, this is electrolysis
265
Q

Chem: when is electrolysis used to extract metals from their ores

A

When the metal is too reactive to be extracted by reduction with carbon or if the metal reacts with carbon, large amounts of energy are used to melt the metal and to produce the electrical current

266
Q

Chem: how can some metals more reactive than carbon be extracted from their ores

A

By melting them end electrolysing them

267
Q

Chem: how is aluminium manufactured with electrolysis

A

A molten mixture of aluminium oxide and cryolite is electrolysed with carbon as the positive electrode (anode)

268
Q

Chem: what are stronger intermolecular forces of attraction or covalent bonds

A

Covalent bonds

269
Q

Chem: why are mixture used as an electrolyte in aluminium elecrtolysis

A

Aluminium oxide is insoluble in water, so it must be molten to act as an electrolyte. However, the melting point of aluminium oxide is high. A lot of energy must be transferred to break its strong ionic bonds, and this is expensive. To reduce costs, powdered aluminium oxide is dissolved in molten cryolite.

270
Q

Chem: why in aluminium electrolysis why must the positive electrode be constantly replaced

A

At the positive carbon electrode carbon dioxide is formed, so the electrode must be replaced frequently

271
Q

chem: what is used to measure the volumes of acid and alkali solutions that react together in a titration reaction

A

a suitable indicator, check

272
Q

Chem: what is this model

A

The nuclear model

273
Q

Chem: what is this model

274
Q

Chem: what is this model of the atom

275
Q

Chem: what is daltons model

A

It is the model of the atom where atoms are tiny spheres that cannot be broken up

276
Q

Chem: an indicator used in titrations

A

Phenolphthalein indicator