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Key Definitions Flashcards

(110 cards)

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1
Q

Mass number

A

The number of protons added to the number of neutrons in the nucleus
The top number on the periodic table

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2
Q

Atomic number

A

Is the number of protons in the nucleus

The bottom number on periodic table

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3
Q

Relative isotopic mass

A

Mass of an atom of an isotope compared to 1/12th the mass of a 12C atom

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4
Q

Isotopes

A

1:
Atoms with the same atomic number but different mass numbers
2:
Atoms that have the same number of protons but different number of neutrons

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5
Q

Orbital

A

Is a region around the nucleus where there is a high probability of finding an electron, can hold 2 electrons with opposite spins

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6
Q

Hunds rule

A

Electrons occupy orbitals singly before pairing happens

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7
Q

Pauli exclusion principle

A

Electrons in the same orbital must have opposite spins

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8
Q

A group

A

Vertical column in periodic table. Electron configuration is the highest occupied shell is the same for all atoms in main group

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9
Q

First ionisation energy

A

Energy per mile needed to remove an electron from gaseous atoms
X(g) -> X 2+ (g) + e-

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10
Q

Second ionisation energy

A

Energy per mile needed to remove an electron from gaseous ions with a single positive charge

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11
Q

Shielding

A

Electron-electron repulsion. It exists between two electrons in the same orbital between electrons in different orbitals

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12
Q

Atomic radius

A

Distance from the centre of the nucleus to the boundary of the Electron cloud, shows periodicity

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13
Q

Ion

A

Charged particle formed when an atom or group of atoms have lost or gained one or more electrons

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14
Q

Ionic bonding

A

Strong electrostatic forces of attraction between oppositely charged ions

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15
Q

Giant ionic lattice

A

Solid ionic compounds comprises oppositely charged ions arranged in a highly ordered way

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16
Q

Isoelectronic ions

A

Have same electronic configuration and number of electrons

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17
Q

Covalent bond

A

Strong electrostatic attraction between two nucleus and the shared pair of electrons between them

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18
Q

Dative covalent bonding

A

Forms when an orbital white a line pair of electrons in one atom overlaps with vacant orbital in another atom

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19
Q

Bond length

A

Distance between the nucleus of two atoms that are covalently bonded together
Measured in nanometres nm

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20
Q

Bond strength

A

Given by the bond enthalpy for a particular covalent bond

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21
Q

Bond enthalpy

A

Enthalpy change when one mole of w bond in the gaseous state is broken

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22
Q

VSEPR theory

A

Valence shell electron pair repulsion, lets you predict shapes of molecules and ions

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23
Q

Electronegativity

A

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

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24
Q

Polar covalent bond

A

Covalent bond is polar is two bonded atoms have different electronegativities

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25
London forces
Type of intermolecular forces, acts between molecules
26
Instantaneous dipole
Don’t need differences in electronegativity, can exist in non polar molecules
27
Induced dipoles
Caused when a molecule comes close to a molecule with a permanent dipole or an instantaneous dipole
28
Hydrogen bonding
Intermolecular force between hydrogen and F O N
29
Solvent
Substance in which another substance can dissolve, forming a solution
30
Solute
Substance that dissolved in the solvent.
31
Soluble
Absolute is soluble if it can dissolve in given solvent
32
Solution
Is the mixture formed between solute and its solvent
33
Hydration
Water molecules surround individual ions and form strong electrostatic attractions with them
34
Metallic bonding
Strong electrostatic force of attraction between metal ions and the delocalised electrons
35
Oxidation number
Represents the number of electrons lost of gained by an atom of that element in a compound or iron
36
Systematic names
When an element can have more than one oxidation state, eg copper 11 oxide, copper 1 oxide
37
Redox reaction
Involves both reduction and oxidation, deceived in terms of transfer of electrons or changes in oxidation number
38
Oxidation
Gain of oxygen Loss of electrons Increase in oxidation number
39
Reduction
Loss of oxygen Gain of electrons Decrease in oxidation number
40
Oxidising agents
Gain electrons, electron acceptors
41
Reducing agents
Lose electrons, they are electron donors
42
Ionic half equations
Shows oxidation from one side of equation and reduction from the other side
43
Spectator ions
Present in a reaction but do not take part in the reaction
44
Ionisation
An atom is ionised if an electron absorbs enough energy to leave it altogether
45
Disproportionation reaction
Element in a single species is simultaneously oxidised and reduces
46
Confirmatory tests
Done to be sure of the identity of the haloed ions
47
Mole
The amount of substance that contains the same number of particles as the number of carbon atoms in exactly 12g of 12C
48
Avogadro constant
6.02 x 10^23 mol -1
49
Relative atomic mass | Ar
The weighted mean mass of an atom of an element compared to 1/12th the mass of a 12C atom
50
Relative formula mass | Mr
Calculated by adding together all Ar values for all the atoms present in a unit of a substance
51
Molar mass
Is the mass per mole of a substance | Unit g mol -1
52
Molecular formulae
Substance shows the actual numbers of atoms of each element in its molecules
53
Empirical formulae
Is the simplest whole number ratio of the atoms of each element it contains
54
Structural formula
Shows each atom and its position | CH3CH2CH2CH3
55
Equation
Balanced when it have same number of atoms of each element in left and right side of equation
56
Avogadro law
Equal volumes of gases under the same conditions of temperature and pressure contain the same number of molecules
57
Molar volume
Vm | 24.0 dm3 mol-1 at RTP
58
Concentration
Of solute in a solution can be measured in Mol dm-3 or in g dm-3
59
Titration
Method in which the volumes of two reacting solutions are measured so that the concentration of one of the solutions can be determined
60
Atom economy
A way to assess chemical reactions, particularly in industrial processes Is measured of how many atoms of the reactants end up in the desired product
61
Percentage yield
Actual yield / theoretical yield x 100 | A way to assess chemical reactions
62
Hydrocarbons
Compounds of hydrogen and carbon only.
63
Alkanes
Hydrocarbon, saturdated, general formula of CnH2n+2
64
Displayed formula
H-c-c-h etc Shows each atom and the bonds it has with other atoms
65
Structural formula
CH4 | Shows each carbon atom and the atoms bonded to it
66
Isomers
Compounds with the same molecular formula but different arrangement of atoms in space
67
Structural isomers
Have same molecular formula but their atoms are arranged in a different order
68
Alkenes
Unsaturated hydrocarbons, with general formula of CnH2n
69
Skeleton formula
Lines to represent each carbon link
70
Position isomers
Structural isomers with same carbon chain but with different functional group
71
Chain isomers
Structural isomers in which carbon chains are different
72
Stereoisomers
Same molecular formula. Same structural formula, different arrangement of atoms
73
E-Z isomers
E isomer is the higher priority groups opposite sides to each other Z isomer the higher priority groups are together
74
Cis-trans isomers
Trans is E, when on opposite sides | Sis is Z when on same side
75
Substituent groups
Atoms or groups attached to the carbon atoms in c double bond
76
Crude oil
Petroleum Mixture of hydrocarbons that can be separated by fractional distillation. Each fraction produced contains hydrocarbons with similar boiling points and chain lengths
77
Fractional distillation
Relies on differences in boiling temperatures of the different hydrocarbons in crude oil
78
Fractions
Crude oil heated and vapours are led into fractionating column hot at bottom and cool at top
79
Cracking
Involves chemical reactions that happen at high temperatures using catalyst zeolites and they decompose larger alkanes to produce smaller alkenes and alkanes u
80
Combustion
Of alkanes is an example of an oxidation reaction, in which oxygen reacts with the hydrogen and carbon atoms in the alkane molecules
81
Complete combustion
Happens when there is sufficient oxygen to oxidise the alkanes fully
82
Incomplete combustion
Happens when there is insufficient oxygen to oxidise the alkanes fully
83
Alternative fuels
Include biodiesel and bioalcohols from renewable sources such as plants
84
Fuel
Is a substance that can release energy usefully through chemical reactions
85
Non renewable
Once they’ve been used up they cannot be replaced
86
Carbon neutral
Refers to activity that has no overall annual carbon emissions to the atmosphere
87
Renewable energy
Eg wind, wave, solar and tidal power
88
Biodiesel
Made of vegetable oils such as rapeseed, sunflower and soya
89
Bioalcohol
Most common -bioethanol. Alcohol derived from materials produced by living organisms
90
Alcohols
Function group -OH
91
Homologous series
Same functional group, same general formula, similar chemical properties
92
Halogenalkanes
Functional group is halogen atom.
93
Radical substitution reactions
Alkanes under go this with halogens to produce halogenalkanes
94
Heterolytic fission
One atom gains both bonding electrons and ions form
95
Homolytic fission
Each atom keeps a bonding electron and radicals form
96
Radical
Species with an unpaired electron
97
Unpaired electron
Represented as a dot, places next to the atom whose bond was broken to form the radical
98
Substitution reaction
One atom or group is replaced by another atom or group
99
Reaction mechanisms
Shows bonds broken or formed and the species (atom or ion or molecule or radical)
100
Sigma bonds
Form end on overlap between two s orbitals, two p orbitals or an s and a p orbital
101
Pi bonds
Sideways overlap between p orbitals once a sigma bond has formed
102
Electrophilic addition reactions
Alkanes undergo reactions with hydrogen halides to produce halogenslkanes
103
Electrophile
Species able to accept a pair of electrons, and are attracted to a region of negative charge
104
Unsymmetrical alkenes
Undergo electrophilic addition reactions in which two products form, a major product and a Minor product
105
Halogenation
Reaction in which a halogen is added to another substance
106
Hydrogenation
Reaction in which hydrogen is added to another substance | Nickel catalyst used in hydrogenation
107
Oxidising agent
Alkanes react with oxidising agent to produce alcohols containing two hydroxyl groups
108
Exothermic
Overall transfer of energy from the system to the surroundings Negative Reactants have more energy than products
109
Endothermic
Overall transfer of energy to system from surroundings Positive Goes up
110
Standard conditions
100Kpa , 298K 1 mol dm-1

Chemistry (10 decks)

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