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A LEVEL CHEMISTRY > ALL DEFINITIONS EVER > Flashcards

ALL DEFINITIONS EVER Flashcards

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1
Q

Concentration

A

The amount of solute in moles dissolved in 1dm3 of solution

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2
Q

Amount of substance

A

The quantity whose unit is the mole. Chemists use amount of substance as a means of counting atoms

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3
Q

Mole

A

The number of atoms of Carbon-12 in 12g of Carbon-12

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4
Q

Avogrado Constant

A

6.02x10(23) - number of atoms per 1 mole of Carbon-12

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5
Q

Molar Mass

A

The mass per mol of a substance. Unit is g/mol

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6
Q

Empirical formula

A

The simplest whole number ratio of atoms of each element in a compound

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7
Q

Molecular formula

A

The actual number of atoms of each element in a molecule

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8
Q

Anhydrous

A

Crystals that have no water molecules in their crystalline structure

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9
Q

Hydrated

A

Crystals that have water molecules as part of their crystalline structure

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10
Q

Water of Crystallisation

A

The water molecules part of a crystalline structure

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11
Q

Solute

A

A material that is dissolved

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12
Q

Solvent

A

A material that does the dissolving

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13
Q

Solution

A

The mixture made from dissolving a solute in a solvent

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14
Q

Standard solution

A

A solution with a known concentration

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15
Q

Concentrated

A

A large number of moles of solute per dm3 of solution

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16
Q

Dilute

A

A small number of moles of solute per dm3 of solution

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17
Q

Ideal gas

A

A hypothetical gas that obeys the gas laws exactly

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18
Q

Ionic bonding

A

The electrostatic attraction between positive and negative ions

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19
Q

Covalent bond

A

The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

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20
Q

Lone pair

A

A pair of electrons in the outer shell not used in bonding

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21
Q

Dative covalent bond

A

A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only

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22
Q

Average bond enthalpy

A

The average enthalpy change which takes place when breaking bonds by homolytic fission 1 mol of a given type of bond in the molecules of a gaseous species

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23
Q

Metallic bonding

A

The electrostatic attraction between positive metal ions and delocalised electrons

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24
Q

Malleable

A

Easily bent into different shapes

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25
Q

Ductile

A

Can be drawn into a wire without breaking

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26
Q

Alloys

A

Mixtures of metals

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27
Q

Electronegativity

A

The ability of an atom to attract the bonding electrons in a covalent bond

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28
Q

Polar covalent bond

A

A bond with a permanent dipole, having positive and negative partial charges of the bonded atoms

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29
Q

Polar molecule

A

A molecule with an overall dipole, having taken into account any dipoles across bonds and the shape of the molecule

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30
Q

Hydrogen bond

A

A strong dipole-dipole attraction between an electron deficient hydrogen atom of NH, OH or HF on one molecule and a lone pair of electrons on a highly electronegative atom (N, O, F) on a different molecule

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31
Q

Group on the periodic table

A

Vertical column - same number of electrons on outer shell and similar chemical properties

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32
Q

Period on the periodic table

A

Horizontal row - elements show trends in properties across the table

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33
Q

Periodicity

A

The regular repeating pattern in properties of the elements across different periods

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34
Q

First Ionisation energy

A

The amount of energy required to remove 1 electron from each atom in a mole of gaseous atoms of an element to form 1 mole of gaseous 1+ ions

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35
Q

Reducing agent

A

Something that donates electrons to something else, enabling reduction to occur. In this process it is oxidised

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36
Q

Oxidising agent

A

Something that accepts electrons from something else, enabling oxidation to occur. In this process it is reduced

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37
Q

Solubility

A

A measure of the ability of a solute to dissolve in a solvent

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38
Q

Alkali

A

A base that releases OH- ions in solution

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39
Q

Alkaline

A

A term used to describe a solution containing hydroxide ions

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40
Q

Alkalinity

A

A measure of the concentration of hydroxide ions present in an alkaline solution

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41
Q

pH

A

A measure of the concentration of hydrogen ions present in a solution

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42
Q

Disproportionation

A

A reaction where the same element is both oxidised and reduced

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43
Q

Enthalpy

A

The measure of the heat energy in a chemical system

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44
Q

System (in terms of enthalpy)

A

The reactants and products

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45
Q

Surroundings (in terms of enthalpy)

A

The rest of the universe

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46
Q

Exothermic

A

Energy is transferred from the system to the surroundings

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47
Q

Endothermic

A

Energy is transferred from the surroundings to the system

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48
Q

Activation energy

A

The minimum energy required to start a reaction by the breaking of bonds

49
Q

Standard enthalpy change of combustion

A

The enthalpy change when 1 mole of substance reacts completely with excess oxygen under standard conditions with all products and reactants in their standard states

50
Q

Standard enthalpy change of formation

A

The enthalpy change when 1 mole of a compound is formed from its elements in their standard states under standard conditions

51
Q

Standard enthalpy change of neutralisation

A

The enthalpy change when the reaction of an acid and a base reacts to form 1 mole of water under standard conditions with all reactants and products in their standard states

52
Q

Hess’s Law

A

If a reaction can take place by more than 1 route and the initial and final conditions are the same, the total enthalpy change is the same for each route

53
Q

Hydrocarbon

A

A molecule containing only carbon and hydrogen

54
Q

Aliphatic

A

A compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings

55
Q

Alicyclic

A

An aliphatic compound arranged in non-aromatic rings with or without side chains

56
Q

Aromatic

A

A compound containing a benzene ring

57
Q

Saturated

A

Single carbon-carbon bonds only

58
Q

Unsaturated

A

The presence of multiple carbon-carbon bonds

59
Q

Homologous series

A

A series of organic compounds having the same functional group and each successive member differing by CH2

60
Q

Functional group

A

A group of atoms responsible for the characteristic reactions of a compound

61
Q

Skeletal formula

A

The simplified organic formula, shown by removing H atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups

62
Q

Displayed formula

A

The relative positioning of atoms and the bonds between them

63
Q

General formula

A

The simplest algebraic formula of a member of a homologous series

64
Q

Structural formula

A

The minimal detail that shows the arrangement of atoms in a molecule

65
Q

Structural isomers

A

Compounds with the same molecular formula but different structural formula

66
Q

Homolytic fission

A

When a covalent bond breaks each bonding atom receives 1 electron, forming 2 radicals

67
Q

Heterolytic fission

A

When a covalent bond breaks 1 bonding atom receives both electrons, forming 1 anion and 1 cation

68
Q

Radical

A

A species with an unpaired electron

69
Q

Pi-bond

A

A bond formed by the sideways overlap of 2 p-orbitals with the electron density above and below the plane of the atom

70
Q

Electrophile

A

An electron acceptor

71
Q

Carbocation

A

A compound that contains a positively charged carbon atom

72
Q

Markownikoff’s rule

A

When a hydrogen halide is added to an unsymmetrical alkene, the most likely product is the one in which the H atom adds to the carbon that already has the most H’s attached to it

73
Q

Atom economy

A

A measure of how well the atoms were utilised

74
Q

% yield

A

Shows us the percentage of how much product was made compared to how much should’ve been made

75
Q

Hydrolysis

A

A chemical reaction involving water or an aqueous solution of a hydroxide that causes the breaking of a bond in a molecule

76
Q

Reflux

A

The continuous evaporation and condensation of a reaction solution back into the original container to ensure the reaction takes place without the contents boiling dry

77
Q

Nucleophile

A

An electron pair donor

78
Q

Elimination

A

The removal of a molecule from a saturated molecule to make an unsaturated molecule

79
Q

Greenhouse effect

A

Warming of the atmosphere due to the trapping of IR by absorption by molecular bonds

80
Q

Lattice enthalpy

A

The enthalpy change when 1 mole of an ionic compound is formed from its ions in the gaseous state under standard conditions

81
Q

First ionisation enthalpy

A

The enthalpy change when 1 electron from each atom in 1 mole of atoms of an element are removed, forming 1 mole of gaseous 1+ ions

82
Q

Standard enthalpy of atomisation

A

The enthalpy change when 1 mole of gaseous atoms are formed from the element in its standard state under standard conditions

83
Q

Standard enthalpy of solution

A

The enthalpy change when 1 mole of a compound is completely dissolved in water under standard conditions

84
Q

Entropy

A

An energy value generally described as disorder. It is related to temperature and quantity

85
Q

Electron affinity enthalpy

A

The enthalpy change when 1 electron is added to each atom in 1 mole of gaseous atoms of an element

86
Q

Acid

A

Proton donor

87
Q

Base

A

Proton acceptor

88
Q

Weak acid

A

An acid that is only partially dissociated in solution

89
Q

Strong acid

A

Fully dissociated in solution

90
Q

Salt

A

Ionic compounds formed when the H+ ions in an acid are replaced by metal or ammonium ions

91
Q

Spectator ions

A

Ions that remain unchanged at after a reaction

92
Q

Redox reaction

A

A reaction where both oxidation and reduction has happened

93
Q

Precipitate

A

The solid formed from a solution during a chemical reaction. Often formed when 2 aqueous solutions are mixed together

94
Q

Ionic equation

A

The balanced symbol equation but with any spectator ions removed

95
Q

Atomic number

A

The number of protons in the nucleus of the atom of an element

96
Q

Isotopes

A

Atoms that have the same number of protons but different number of neutrons

97
Q

Mass number

A

The number of protons plus the number of neutrons

98
Q

Relative isotopic mass

A

The mass of 1 atom of an isotope compared to 1/12 the mass of 1 atom of Carbon-12

99
Q

Relative atomic mass

A

The weighted mean mass of 1 atom of an element compared to 1/12 the mass of 1 atom of Carbon-12

100
Q

Relative molecular mass

A

The weighted mean mass of a molecule compared to 1/12 the mass of 1 atom of Carbon-12

101
Q

Relative formula mass

A

The weighted mean mass of a formula unit compared to 1/12 the mass of 1 atom of Carbon-12

102
Q

Reduction

A

Gain of electrons

103
Q

Oxidation

A

Loss of electrons

104
Q

Addition polymerisation

A

Formation of a very long molecular chain, by repeated addition reactions of many unsaturated alkene molecules (monomers)

105
Q

Alkyl group

A

A side chain formed by removing a hydrogen atom removed from an alkane parent chain

106
Q

Orbital

A

A region around the nucleus that can hold up to two electrons, with opposite spins

107
Q

Fingerprint region

A

An area of an infrared spectrum below 1500 that gives a characteristic pattern for different compounds

108
Q

Fragment ions

A

Ions formed from the breakdown of the molecular ions in a mass spectrometer

109
Q

Fragmentation

A

The process in mass spectrometry that causes a positive ion to split into smaller pieces, one of which is a positive fragment ion

110
Q

Intermolecular force

A

Attractive force between molecules. Intermolecular forces can be London forces, permanent dipole-dipole interactions or hydrogen bonding

111
Q

Molecular ion

A

The positive ion formed in mass spectrometry when a molecule loses an electron

112
Q

Nucleophilic substitution

A

A reaction in which a nucleophile is attracted to an electron deficient carbon atom, and replaces an atom or group of atoms on the carbon atom

113
Q

Sigma bond

A

A bond formed by the overlap of one orbital from each bonding atom, consisting of two electrons and with the electron density centred around a line directly between the nuclei of the two atoms

114
Q

Shell

A

A group of orbitals with the same principal quantum number

115
Q

Standard enthalpy change of hydration

A

The enthalpy change when 1 mole of isolated gaseous ions is dissolved in water, forming 1 mole of aqueous ions under standard conditions

116
Q

Standard enthalpy change of reaction

A

The enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, all reactants and products in their standard states

117
Q

Stereoisomers

A

Compounds with the same structural formula but with different arrangement of the atoms in the space

118
Q

Sub-shell

A

A group of the same type of orbitals within a shell

119
Q

Volatility

A

The ease at which a liquid turns into a gas. Increases as boiling point decreases

A LEVEL CHEMISTRY (6 decks)

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