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All Chemistry Definitions Flashcards

1
Q

Atomic Number

A

The number of protons and neutrons in the nucleus of an atom

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2
Q

Electron

A

A fundamental particle found in the energy levels of an atom with a relative mass of 1/2000 and a relative charge of -1

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3
Q

Isotope

A

Atoms of the same element that have different numbers of neutrons

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4
Q

Mass number

A

The total number of protons and neutrons in a nucleus

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5
Q

Neutron

A

A fundamental particle found in the nucleus of atoms with a relative mass of 1 and a relative charge of 0

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6
Q

Proton

A

A fundamental particle found in the nucleus of atoms with a relative mass of 1 and a relative charge of +1

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7
Q

Anion

A

A negatively charged ion

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8
Q

Cation

A

A positively charged ion

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9
Q

Empirical formula

A

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

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10
Q

Molecular formula

A

Shows the actual number of atoms of each element in a compound

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11
Q

Molecule

A

A small group of atoms held together by covalent bonds e.g. H₂O, Cl₂, CH₄ etc

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12
Q

Orbital

A

A region of space around the nucleus of an atom which holds up two electrons with opposite spins

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13
Q

Covalent bond

A

A shared pair of electrons

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14
Q

Dative covalent bond (coordinate bond)

A

A shared pair of electrons which has been provided by only one atom

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15
Q

Electronegativity

A

A measure of the ability of an atom to attract the pair of electrons in a covalent bond

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16
Q

Giant covalent lattice

A

A three dimensional structure of oppositely charged ions held together by electrostatic attraction

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17
Q

Hydrogen bond

A

A strong dipole-dipole attraction between an electron deficient hydrogen atom on one molecule and a lone pair on the O, N or F atoms of a different molecule

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18
Q

Intermolecular force

A

An attractive force between molecules

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19
Q

Ionic bond

A

The electrostatic attraction between oppositely charged ions

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20
Q

Lone pair

A

An outer shell pair of electrons that is not involved in bonding

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21
Q

Metallic bond

A

The electrostatic attraction between positive metal ions and delocalised electrons

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22
Q

Permanent dipole

A

A small charge difference across a bond as a result of a difference in electronegativity

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23
Q

Permanent dipole-dipole force

A

A relatively weak attractive force between permanent dipoles in neighbouring molecules

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24
Q

Simple molecular lattice

A

A three dimensional structure of molecules held together by weak intermolecular forces

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25
Induced dipole-dipole (London) forces
A relatively weak attractive force between induced dipoles in neighbouring molecules
26
Alicyclic
An aliphatic compound arranged in non-aromatic rings without side chains
27
Aliphatic
A compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings
28
Aromatic
A compound containing at least one benzene ring
29
Displayed formula
A formula which shows the relative positions of all the atoms and the bonds between them
30
Functional group
The reactive part of an organic molecule / the part of an organic molecule which gives it its characteristic properties or reactions
31
General formula
The simplest formula for a homologous series
32
Homologous series
A series of organic compounds having the same functional group but with each member differing by CH2
33
Skeletal formula
A simplified formula with hydrogen atoms removed from alkyl chains leaving only a carbon backbone drawn as a zig-zag and associated functional groups
34
Structural formula
A formula showing the minimal detail for the arrangement of atoms in a molecule in e.g. CH₃CH₂CH₂CH₂CH₃ or CH₃(CH₂)₃CH₃
35
Molecule
A small group of atoms held together by covalent bonds
36
Concentration
The moves of a solute dissolved per 1 dm^3 of solution
37
Molar mass
The mass in grams per mole of a substance (g mol^-1)
38
Molar volume
The volume that 1 mole of of gas occupies at room temperature and pressure (24dm^3)
39
Relative atomic mass
The weighted mean mass of an atom compared with 1/12 of the mass of an atom of carbon-12
40
Relative formula mass
The weighted mean mass of a formula unit compared with 1/12 of the mass of an atom of carbon-12
41
Relative isotopic mass
The weighted mean mass of an isotope compared with 1/12 of the mass of an atom of carbon-12
42
Relative molecular mass
The weighted mean mass of a molecule compared with 1/12 of the mass of an atom of carbon-12
43
Standard solution
A solution of known concentration
44
Stoichiometry
The molar relationship between the substances involved in a chemical relationship
45
The Avogadro Constant
The number of atoms per mole of the Carbon-12 (6.02x10^23)
46
Acid
A proton (H+) donor
47
Alkali
A soluble base which dissolves in water to form hydroxide ions (OH-) e.g. NaOH, Ca(OH)₂ (used to neutralise acid in soils), Mg(OH)₂ (used to cure acid indigestion)
48
Acid
A proton (H+) donor
49
Alkali
A soluble base which dissolves in water to form hydroxide ions (OH-) e.g. NaOH, Ca(OH)₂ (used to neutralise acid soils), Mg(OH)₂ (used to cure acid indigestion)
50
Anhydrous salt
A salt not containing water of crystallisation
51
Base
A proton (H+) acceptor
52
Hydrated salt
Salt containing water of crystallisation
53
Salt
A compound formed when and H+ ion form and acid is replaced by a metal ion or ammonium ion
54
Water of crystallisation
Water molecules contained within crystals of a hydrated salt
55
Disproportionation
A reaction where the same element is oxidised and reduced
56
Oxidation
The loss of electrons or increase in oxidation number
57
Oxidation number
A measure of the number of electrons an atom used to bond with atoms of another element
58
Oxidising agent
A reagent which oxidises (takes electrons from) another species. An electrons acceptor
59
Redox reaction
A reaction which involves both reduction and oxidation
60
Reducing agent
A reagent which reduces (adds electrons to) another species. An electron donor
61
Reduction
The gain of electrons or increase in oxidation number
62
Electron shielding
The repulsion between electrons in different inner shells
63
Sub shell
A group of the same type of atomic orbital (s, p, d, f) s sub-shells contain ONE s-orbital (2 electrons) p sub-shells contain THREE p-orbitals (6 electrons) d sub-shells contain FIVE d-orbitals (10 electrons) f sub-shells contain SEVEN f-orbitals (14 electrons),
64
Bonding pair
An outer shell pair of electrons involved in bonding
65
Giant ionic lattice
A three dimensional structure of oppositely charged ions held together by strong ionic bonds i.e. ALL IONIC COMPOUNDS
66
Anhydrous salt
Salt not containing water of crystallisation
67
Base
A proton (H+) acceptor
68
Hydrated salt
Salt containing water of crystallisation
69
Salt
A compound formed when an H+ ion from an acid is replaced by a metal or ammonium ion
70
Water of crystallisation
Water molecules contained within crystals of hydrated salt (separated from the anhydrous part by a dot in the formula)
71
Disproportionation
A reaction where the same element is oxidised and reduced
72
Oxidation
The loss of electrons or an increase is oxidation number
73
Oxidation number
A measure of the number of electrons an atom uses to bond with atoms of another element
74
Oxidising agent
A reagent which oxidises (takes electrons from) another species. An electron acceptor
75
Redox reaction
A reaction which involves both reduction and oxidation
76
Reducing agent
A reagent which reduces (adds electrons to) another species. An electron donor
77
Reduction
The gain of electrons or a decrease in oxidation number
78
Electron shielding
The repulsion between electrons in different inner shells
79
Bonding pair
An outer shell pair of electrons involved in bonding
80
Giant ionic lattice
A three dimensional structure of oppositely charged ions held together by strong ionic bonds
81
First ionisation energy
The energy required to remove one electrons from each atom in a mole of atoms in the gas phase (kJ mol^-1)
82
Periodicity
The regular repeating of properties of the elements across the periodic table
83
Successive ionisation energies
A measure of the energy required to remove each electron in turn
84
Diatomic molecule
A covalent molecule consisting of 2 bonded atoms e.g. Cl₂
85
Activation energy
The minimum energy required for a reaction to occur
86
Endothermic
The reaction in which the enthalpy of the products is greater than the enthalpy of the reactants
87
Enthalpy
The heat content of a chemical measured at constant pressure
88
Exothermic
A reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants
89
Hess’ Law
The enthalpy change of a reaction is independent of the route it only depends on the initial and final station
90
Mean bond enthalpy
The enthalpy change that takes place when 1 mole of a specified bond is broken into its atoms in the gas phase averaged over many compounds containing that bond
91
Specific heat capacity
The energy in joules required to raise the temperature of 1g of a substance by 1 K
92
Standard conditions
Pressure of 100kPa, temperature of 298K (25°C), and aqueous solutions of concentration 1.00 mol dm^-3
93
Standard enthalpy change of combustion
The enthalpy change when 1 mole of a substance reacts completely with oxygen measured under standard conditions
94
What is a buffer?
A solution that can resist significant changes in the pH when small amounts of an acid or base are added to it
95
Conjugate acid-base pair
A pair of chemical species that differ by one proton (H+) where one acts as an acid by donating the proton and one acts as a base by accepting the proton
96
The standard enthalpy change of formation
The enthalpy change when one mole of a substance is formed from its elements measured under standard conditions
97
The standard enthalpy change of reaction
The enthalpy change for a chemical reaction for the quantities in the chemical equation measured under standard conditions
98
The standard enthalpy change of neutralisation
The enthalpy change for a chemical reaction between an aqueous alkali to produce 1 mole of water measured under standard conditions
99
Enthalpy change of atomisation
The enthalpy change when one mole of gaseous atoms is formed from its element in its standard state
100
Enthalpy change of hydration
The enthalpy change when one mole of isolated gaseous ions is dissolved in water forming one mole of aqueous ions
101
Enthalpy change of solution
The enthalpy change when one mole of a compound is completely dissolved in water under standard conditions

Chemistry Flashcards (7 decks)

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