Chem Definitions 🔭⚗️

Front 1

Atomic number

Back 1

The number of protons in the nucleus of an atom

Hint 1

Protons in

Front 2

Mass Number

Back 2

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

Hint 2

Number of isotopes

Front 3

Isotopes

Back 3

Atoms of the same element (same number of protons and electrons) With a different number of neutrons

Hint 3

Atoms of

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Atomic orbital

Back 4

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

Hint 4

A region around

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P block element

Back 5

Element which has the highest energy electron in a p sub shell

Hint 5

Element which

Front 6

First ionisation energy

Back 6

The energy required to remove One electron from each atom in One mole of gaseous atoms to form one mole of gaseous 1+ ions kjmol

Hint 6

Energy required

Front 7

Successive ionisation energy

Back 7

Measure of the energy required to remove one electron in turn

Hint 7

In turn

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Acid

Back 8

Proton donor

Hint 8

Donor

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Base

Back 9

Proton acceptor

Hint 9

Acceptor

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Alkali

Back 10

Base that dissolves in water and releases 0H- ions in aqueous solution

Hint 10

OH-

Front 11

Salt

Back 11

Compound produced when a H+ ion from an acid is replaced with a metal ion or another positive ion such as an ammonium ion

Hint 11

Replaced

Front 12

Molar Mass

Back 12

The mass in grams per mole of a substance gmol

Hint 12

In G

Front 13

Relative isotopic mass

Back 13

The mass of an atom of an isotope compares with 1/12 the mass of an atom of carbon 12

Hint 13

Of an atom

Front 14

Relative atomic mass

Back 14

The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon 12

Hint 14

Weighted

Front 15

Mole

Back 15

Amount of substance containing as many particles as there are carbon atoms in exactly 12 g of carbon 12

Hint 15

Amount

Front 16

Avogadro's constant

Back 16

Number of particles per mole of a substance 6.02×10^23

Front 17

Empirical formula

Back 17

The Simplest whole number ratio of atoms of each element present in a compound

Hint 17

Ratio

Front 18

Molecular formular

Back 18

The actual number of atoms of each element in a molecule

Hint 18

Actual

Front 19

Water of crystallisation

Back 19

Water present in a compound giving the compound a crystalline appearance

Hint 19

Appearence

Front 20

Water of crystallisation

Back 20

Water present in a compound giving the compound a crystalline appearance

Hint 20

Appearence

Front 21

Anhydrous

Back 21

When all the water of crystallisation have been removed from a compound

Hint 21

Removed

Front 22

Water of crystallisation

Back 22

Water present in a compound giving the compound a crystalline appearance

Hint 22

Appearence

Front 23

Anhydrous

Back 23

When all the water of crystallisation have been removed from a compound

Hint 23

Removed

Front 24

Hydrated

Back 24

When water of crystallisation is present in a compound

Hint 24

When

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Metallic bonding

Back 25

Strong electrostatic attraction between metal cations (positive ions) and delocalised electrons (The giant metallic lattice structure)

Hint 25

Electrostatic

Front 26

Ionic Bond

Back 26

The electrostatic attraction between oppositely charged ions

Hint 26

Between

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Covalent bond

Back 27

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

Hint 27

Strong

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Covalent bond

Back 28

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

Hint 28

Strong

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Dative co-ordinate bond

Back 29

Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonding atoms, where one of the atoms supply is both of the electrons shared

Hint 29

Both

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Covalent bond

Back 30

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

Hint 30

Strong

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Dative co-ordinate bond

Back 31

Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonding atoms, where one of the atoms supply is both of the electrons shared

Hint 31

Both

Front 32

Electronegativity

Back 32

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

Hint 32

Bonding electrons

Front 33

Electron pair repulsion theory

Back 33

• electron pairs repel each other as far apart as possible

• lone pairs of electrons repel more stronger than bonding pairs of electrons

Front 34

Oxidation number

Back 34

A measure of the number of electrons that an atom uses to bond atoms of another element

Hint 34

Uses

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Oxidation

Back 35

Loss of electrons and increase in oxidation number

Hint 35

Loss

Front 36

Reduction

Back 36

Gaining electrons and loss in oxidation number

Hint 36

Gain

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Oxidising agent

Back 37

Reagent that oxidises another species (Itself reduced)

Front 38

Oxidising agent

Back 38

Reagent that oxidises another species (Itself reduced)

Front 39

Reducing agent

Back 39

A Reagent that reduces another species (itself oxidised)

Front 40

Redox

Back 40

Reaction were both oxidation and reduction take place

Hint 40

Both

Front 41

Periodicity

Back 41

Repeating trends in the physical and chemical properties across different periods

Hint 41

Repeating trends

Front 42

Displacement reaction

Back 42

A reaction in which a more reactive element (halogen) displaces a less reactive element (halogen) from an aqueous solution of its halide ions

Front 43

Disproportionation

Back 43

Reaction in which the same element is oxidised and reduced

Front 44

Enthalpy Change

Back 44

Amount of heat released or absorbed Chemical reaction, carried out under constant pressure Kjmol-1

Front 45

Enthalpy Change

Back 45

Amount of heat released or absorbed Chemical reaction, carried out under constant pressure Kjmol-1

Front 46

Exothermic reaction

Back 46

Reaction in which heat energy is released into the surroundings ( H- )

Front 47

Endothermic reaction

Back 47

A reaction in which heat energy is absorbed from the surroundings

Front 48

Average bond enthalpy

Back 48

Average enthalpy change when one mole of gaseous bonds are broken by homolytic fission

Front 49

Standard conditions

Back 49

•25° C or 298K

• 1 atmosphere pressure or 100kPa

• 1.0dm^3 concentration

Front 50

Standard states

Back 50

Physical states under standard conditions

Front 51

Standard states

Back 51

Physical states under standard conditions

Front 52

Standard enthalpy change of a reaction

Back 52

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

Hint 52

Accompanies

Front 53

Standard enthalpy change of neutralisation

Back 53

Change that accompanies the neutralisation of an aqueous acid by an aqueous base form one mole of H2O under standard conditions

Front 54

Standard enthalpy change of formation

Back 54

The Enthalpy change when One mole of a compound is formed from its constituent elements in their standard states under standard conditions

Front 55

Standard enthalpy change of combustion

Back 55

The enthalpy change when one mole of a substance reacts completely with oxygen understand the conditions all products and reactants in their standard states

Front 56

Hess' Law

Back 56

The enthalpy change of reaction depends only on the initial and final states and is independent on the route taken

Front 57

Activation energy

Back 57

Minimum energy required to start a reaction by the breaking of bonds in the reactants

Front 58

Activation energy

Back 58

Minimum energy required to start a reaction by the breaking of bonds in the reactants

Front 59

Catalyst

Back 59

Increases the rate of reaction without being used up by the overall reaction

Front 60

Hydrocarbon

Back 60

Compounds containing only hydrogen and carbon

Front 61

Homologous series

Back 61

Series of organic compounds having the same functional group but with each successive member differing by CH2

Front 62

Structural isomers

Back 62

Compounds with the same molecular formula but different structural formula

Front 63

Structural isomers

Back 63

Compounds with the same molecular formula but different structural formula

Front 64

Stereo isomerism

Back 64

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

Front 65

Structural isomers

Back 65

Compounds with the same molecular formula but different structural formula

Front 66

Stereo isomerism

Back 66

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

Front 67

E/Z isomerism

Back 67

An example of stereoisomerism in which there is a restricted rotation around a C=C double bond, and each of the CC double bond have two different groups attached to it.

Front 68

Cis/Trans Isomerism

Back 68

A special case of ez isomerism in which there is a hydrogen atom on each carbon atom of the CC double bond

Front 69

Radical

Back 69

Species with an unpaired electron

Front 70

Curly arrow

Back 70

The movement of an electron pair showing either heterolytic fission or the formation of a covalent bond

Front 71

Electophile

Back 71

Electron pair acceptor

Front 72

Nucleophile

Back 72

Electron pair donor

Front 73

Substitution reaction

Back 73

Reaction where atom or group in a molecule is replaced by another atom or group

Front 74

Addition reaction

Back 74

Reaction where a group is added over the double bond of another atom or group

Front 75

Elimination reaction

Back 75

Reaction where an atom or group is removed from a molecule to make an unsaturated molecule

Front 76

Oxidation reaction

Back 76

Reaction where oxygen is added and/or hydrogen is removed from a molecule

Front 77

General formula

Back 77

CnH2n+2

Front 78

Structural formula

Back 78

CH3CH2CH3

Front 79

Displayed formula

Back 79

Showing all the bonds

Front 80

Skeletal formula

Back 80

Showing the bonds only and functional groups

Front 81

Functional group

Back 81

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

Front 82

Aliphatic

Back 82

Compound containing carbon and hydrogen join together in straight chains, branched chains or non-aromatic rings

Front 83

Alicyclic

Back 83

And aliphatic compound arranged and non-aromatic rings with or without sidechains

Front 84

Aromatic

Chem

Back 84

Compound containing a benzene ring

Front 85

Condensation reaction

Back 85

A reaction where a H2O molecule is lost when two molecules are joined together

Front 86

Dehydration reaction

Back 86

A reaction where a H2O molecule is removed from a saturated molecule to form an unsaturated molecule

Front 87

Hydrolysis reaction

Back 87

Chemical reaction involving water or an aqueous solution, which causes the breaking of a bond, splitting a reactant molecule into two products

Front 88

Sigma Bond

Back 88

Single end-on (axial) overlap of orbitals directly between bonding atoms, allowing free rotation of the bond

Front 89

Pi Bond

Back 89

Double sideways overlap of adjacent P orbitals above and below the plane of bonding atoms, with restricted rotation of the bond

Front 90

Volatility

Back 90

Ease with which a liquid turns into a gas

Front 91

Precipitate

Back 91

And insoluble solid formed when two solutions are mixed together

Front 92

Distillation

Back 92

Is the technique of heating a liquid to create vapour which is collected when cooled and condensed, separate from the original liquid

Front 93

Heat under reflux

Back 93

The continuous boiling and condensing of the liquid preventing loss of volatile liquids from a heated reaction vessel