AQA Chemistry A-Level > Definitions > Flashcards

Definitions Flashcards

All Papers - Includes Physical, Inorganic and Organic (97 cards)

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1
Q

Define

Relative Atomic Mass

A

The weighted average mass of an element, taking into account the abundance of its naturally occuring isotopes, relative to 1/12th of carbon-12.

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2
Q

Define:

Mass Number

A

The number of protons and Neutrons

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3
Q

Define:

Atomic Number

A

Number of Protons

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4
Q

Define:

Isotope

A

Different versions of an element with the same number of protons but different number of neutrons.

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5
Q

Define:

Relative Isotopic Mass

A

The mass of an isotope relative to 1/12th the mass of carbon-12.

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6
Q

Define:

Relative Molecular Mass

A

The mass of the molecule compared to 1/12 of Carbon-12

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7
Q

Define:

Avogrado’s Constant

A

The number of atoms in 12g of Carbon-12

(6.022 x10^(23) atoms)

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8
Q

Define:

A mole

A

the amount of substance that contains 6.022 x10^(23) particles

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9
Q

Define:

Empirical Formula

A

Formula to show the simplest ratio of atoms of each element in a substance

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10
Q

Define:

Molecular Formula

A

Formula to indicate the number of atoms of each element in one molecule.

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11
Q

Define:

Electronegativity

A

The power of an atom to attract the pair of electrons in a covalent bond towards itself.

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12
Q

Define:

Enthalpy

A

A measure of the heat content of a substance

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13
Q

Define Enthalpy Change

A

Change in heat content under standard conditions

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14
Q

Define:

Enthalpy of Formation

(and Exo/Endo)

A

Enthalpy change when one mole of substance is formed from its constituent elements with all reactants and products in their standard states, under standard conditions.

(Exothermic)

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15
Q

Define:

Enthalpy of Combustion

(and Exo/Endo)

A

Enthalpy change when one mole of a substance undergoes complete combustion in oxygen, with all reactants and products in their standard states under standard conditions.

(Exothermic)

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16
Q

Define:

Enthalpy of Neutralisation

(and Exo/Endo)

A

The Enthalpy when one mole of water is formed in a reaction between acid and alkalai under standard conditions.

Exothermic

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17
Q

Define:

Le Chatelier’s Principle

A

When a system at equilibrium is subjected to a change in conditions, the equilibrium postiion shifts to try and oppose that change.

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18
Q

Define:

Reversible Reaction

A

A reaction that can go on both the forward and reverse direction

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19
Q

Define:

Static Equilibria

A

The concentration of the reactions and products does not change as both the forward and reverse reaction rates are zero.

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20
Q

Define:

Dynamic Equilibrium

A

The concentration of both the products and reactants does not change as both the forward and reverse reaction rate are equal.

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21
Q

Define:

A closed system

A

A system in which neither the reactants nor products can leave or enter

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22
Q

Define:

Oxidation

A

Loss of Electrons
Gain of Oxygen
Loss of Hydrogen

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23
Q

Define:

Reduction

A

Gain of Electrons
Loss of Oxygen
Gain of Hydrogen

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24
Q

Define:

Oxidising Agent

A

Species that removes electrons from another

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25
# Define: Reducing Agent
Species that gives electrons to another
26
# Define: Periodicity
Trends seen across the periods
27
# Define: Ionisation Enthalpy - First Ionisation Energy | (and Exo/Endo)
Enthalpy change when each atom in one mole of gaseous atoms looses one electron to form one mole of gaseous 1+ ions. ## Footnote Endothermic
28
# Define: Ionisation Enthalpy - Second Ionisation Enthalpy | (and Exo/Endo)
Enthalpy change when each ion in one mole of gaseous 1+ ions looses one electron to form one mole of gaseous 2+ ions. ## Footnote Endothermic
29
# Define: First Electron Affinity | (and Exo/Endo)
Enthalpy change when each atom in one mole of gaseous atoms gains one electron to form one mole of gaseous 1- ions. ## Footnote Exothermic
30
# Define: Second Electron Affinity | (and Exo/Endo)
Enthalpy change when each ion in one mole of gaseous 1- ions gains one electron to form one mole of gaseous 2- ions. ## Footnote Endothermic
31
# Define: Enthalpy of Atomisation | (and Exo/Endo)
Enthalpy Change when one mole of gaseous atoms is formed from an element in its standard state. ## Footnote Endothermic
32
# Define: Hydration Enthalpy | (and Exo/Endo)
Enthalpy Change when one mole of gaseous ions forms aqueous ions ## Footnote Exothermic
33
# Define: Enthalpy of Solution | (and Exo/Endo)
Enthalpy when one mole of ionic solid dissolves in a volume of water large enough so that the dissolved ions are well separated and do not interact with each other. ## Footnote Varies
34
# Define: Bond dissociation Enthalpy | (and Exo/Endo)
Enthalpy change when one mole of covalent bonds is broken in the gaseous state. ## Footnote Endothermic
35
# Define: Lattice enthalpy of formation | (and Exo/Endo)
Enthalpy Change when one mole of solid ionic compound is formed from its constituent ions in the gas phase ## Footnote Exothermic
36
# Define: Lattice enthalpy of Dissociation | (and Exo/Endo)
Enthalpy change when one mole of solid ionic compound is broken up into its constiuent ions in the gas phase ## Footnote Endothermic
37
# Define: Enthalpy of Fusion | (and Exo/Endo)
Enthalpy when one mole of a solid is turned into a liquid ## Footnote Endothermic
38
# Define: Enthalpy of Vapourisation | (and Exo/Endo)
Enthalpy when one mole of liquid is turned into a gas ## Footnote Endothermic
39
# Define: Mean Bond Enthalpy
The enthalpy to break one mole of covalent bonds in the gas phase into gaseous atoms averaged over several compounds.
40
# Define: Entropy
A measure of chemical disorder. | The more disordered something is, the greater the entropy. ## Footnote Gases have the most entropy, as particles are moving rapidly and randomly, whilst solids have the least entropy. - There is a tendancy for entropy to increase.
41
# Define Chiral Carbon/ Chiral Centre
A carbon bonded to 4 different groups.
42
# Define Optical Isomerism
A type of sterioisomerism that occurs as a result of a chiral centre in a molecule, forming two super impossible molecules. Optical Isomers have opposite effects on planes of polarised light.
43
# Define: Racemix
A mixture containing equal amounts of enantiomers. ## Footnote This means it will have no effect on a ray of polarised light, as the racemix will bend the light equally in opposite directions.
44
# Define: Enantiomers
Molecules which are non superimposible mirror images of each other.
45
# Define: Carbonyl Group
a functional group with a C=O bond.
46
# Define: Esterification
The reaction of Carboxyllic acids with alcohols under reflux in the presence of a strong catalyst.
47
# Define: Nucleophile
Electron pair donor
48
# Define: Electrophile
Electron Pair Acceptor
49
# Define: Halogen
An element in group 7, e.g. Fluorine, Chlorine, Bromine or Iodine
50
# Define: Halide
The negative ion of a halogen, e.g. Fluoride, Bromide, Chloride or Iodide
51
# Define: Aliphatic
Organic Compound containg C chains and branches
52
# Define: Aromatic
Organic compounds containing one or more benzene ring.
53
# Define: Carbocation
A positive ion with the positive charge on a C atom
54
# Define: Dehydration
The elimination of water
55
# Define: Dehydrogenation
The elimination of hydrogen
56
# Define: Free Radical
Species with an unpaired electron
57
# Define: Functional Group
The atom or group of atoms that is responsible for most of the chemical reactions of a molecule.
58
# Define: Homologous Series
A family of compounds with the same general formula and similar chemical properties. In a series each member differs by the addition of a CH2 group and there is a gradual change in physical properties
59
# Define: Hydration
Addition of water
60
# Define: Hydrocarbon
Molecule containing hydrogen and carbon only
61
# Define: Hydrogenation
The addition of Hydrogen.
62
# Define: Hydrolysis
A reaction involving the breaking of bonds due to reaction with water
63
# Define: Saturated
Molecule containing no double bonds
64
# Define: Stereoisomers
Molecules with the same molecular and structural formula but different spatial arrangement of atoms
65
# Define: Geometric Isomers
*Type of Stereo-Isomerism* - molecules which have different arrangement of groups around a C=C bond
66
# Define: Optical Isomers
*Type of Stereo-isomerism* - molecules which are non-superimposable mirror images
67
# Define: Structural Isomers
Molecules with the same molecular formula but different structural formula.
68
# Define: Chain isomers
*Type of structural isomerism* Structural isomers that differ by having a different carbon chain
69
# Define: Postion Isomer
*Type of structural isomerism* Structural isomer that differs by having the functional group in a different position
70
# Define: Functional Group Isomer
*Type of structural isomerism* Structural isomer that differ by having a different functional group
71
# Define: Unsaturated
Molecule contain double bond/ bond.
72
# Define: Polymer
A long chain molecule made of many monomers
73
# Define: Monomer
the smallest unit in a polymer
74
# Define: Addition Polymerisation
A polymer formed by bonding many monomers without generating any other products
75
# Define: Carbon Neutral
A process which releases the same amount of CO2 as is taken in.
76
# Define: Transition Metal
An element that has an incomplete d subshell in one of its common ions
77
# Define: Ligand
A species which can use lone pairs of electrons to covalently bond to a metal
78
# Define: Complex
A metal ion with coordinatley bonded ligands
79
# Define: Coordination Number
The number of coordinate bonds each metal ion has to ligands
80
# Define: Lewis Base
A lone pair donor
81
# Define: Lewis Acid
A lone pair acceptor
82
# Define: Heterogeneous catalyst
A catalyst that is in a different phase to the reactants
83
# Define: Homogeneous catalyst
A catalyst which is in the same phase as the reactants
84
# Define: Ligand Substitution
Where one ligand is replaced by another ligand
85
# Define: Unidentate ligands
Ligands which form one coordinate bond to a metal ion
86
# Define: Bidentate Ligands
Ligands which form two coordiante bonds to a metal ion
87
# Define: Multidentate Ligands
Ligands which form more than two coordinate bonds with a metal ion
88
# Define: Base
A proton acceptor
89
# Define: Bronsted-Lowry Acid
Proton Donor (H+)
90
# Define: Bronsted-Lowry Base
Proton Acceptor (H+)
91
# Define: Bronsted-Lowry Acid-Base reaction
A reaction involving the transfer of a proton
92
# Define: Monoprotic Acid
Acid which releases one H+ ion per molecule | e.g. HCl
93
# Define: Diprotic Acid
Acid that releases two H+ ions per molecule | e.g. H2SO4
94
# Define: pH
-log[H+] | so [H+] = 10^(-pH)
95
# Define: Neutral pH
when [H+] = [OH-]
96
# Define: Buffer Solution
Solution that resists change in pH when small amounts of acid or alkalai are added | (Note- the pH does change just not very much)
97
# Define: Zwitterion
A species that has both a positive and negative charge on different parts of the particle, forming a net charge of zero.
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