CCEA Definitions AS1

Question 1

Molecular ion

Answer 1

Two or more atoms covalently bonded with an overall charge

Question 2

Avogadro’s Constant

Answer 2

Number of atoms in 12.000g of carbon-12

Question 3

Mole

Answer 3

The amount of substance which contains the Avogadro constant of atoms, molecules, or group of ions.

Question 4

Molar mass

Answer 4

The mass of one mole of a substance.

Question 5

Anhydrous

Answer 5

A salt which contains no water of crystallisation.

Question 6

Hydrated

Answer 6

A salt which contains water of crystallisation.

Question 7

Water of crystallisation

Answer 7

Water chemically bonded within a crystal structure.

Question 8

Atomic Number

Answer 8

The number of protons in the nucleus of an atom.

Question 9

Mass number

Answer 9

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

Question 10

Relative Atomic Mass (RAM)

Answer 10

The average mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12.

Question 11

Relative Isotopic Mass (RIM)

Answer 11

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

Question 12

Isotopes

Answer 12

Atoms which have the same atomic number but a different mass number.

Question 13

Relative Formula Mass (RFM)

Answer 13

The average mass of a formula unit relative to 1/12th of the mass of an atom of carbon-12.

Question 14

Relative Molecular Mass (RMM)

Answer 14

The average mass of a molecule relative to 1/12th of the mass of an atom of carbon-12.

Question 15

First Ionisation Energy

Answer 15

The energy required to convert one mole of gaseous atoms into gaseous ions with a single positive charge.

Question 16

Second Ionisation Energy

Answer 16

The energy required to convert one mole of gaseous ions with a single positive charge into gaseous ions with a double positive charge.

Question 17

Third Ionisation Energy

Answer 17

The energy required to convert one mole of gaseous ions with a double positive charge into gaseous ions with a triple positive charge.

Question 18

Covalent Bond

Answer 18

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

Question 19

Dative Bond

Answer 19

A shared pair of electrons between two atoms - One atom provides both electrons.

Question 20

Octet Rule

Answer 20

When reacting, an atom tends to gain, lose, or share electrons to achieve 8 in its outer shell.

Question 20

Electronegativity

Answer 20

The extent to which an atom attracts the bonding electrons in a covalent bond.

Question 21

Polar bond

Answer 21

A covalent bond in which there is unequal sharing of the bonding electrons.

Question 22

Delocalised electrons

Answer 22

Outer electrons do not have fixed positions but move freely.

Question 23

Intermolecular

Answer 23

Between neighbouring molecules.

Question 24

van der Waals' Forces

Answer 24

The attraction between instantaneous and induced dipoles on neighbouring molecules.

Question 25

Permanent dipole-dipole attraction

Answer 25

Attraction between the positive end of the permanent dipole on a molecule with the negative end of the permanent dipole of a neighbouring molecule.

Question 26

Hydrogen bond

Answer 26

The attraction between a lone pair of electrons on a very electronegative atom (N,O,F) in one molecule and a hydrogen atom in a neighbouring molecule, in which the hydrogen atom is covalently bonded to a very electronegative atom (N,O,F).

Question 27

Redox

Answer 27

Oxidation and reduction occur in the same reaction at the same time.

Question 28

Oxidation

Answer 28

Loss of electrons/increase in oxidation state.

Question 29

Reduction

Answer 29

Gain of electrons/decrease in oxidation state.

Question 30

Oxidising agent

Answer 30

electron acceptor

Question 31

Reducing agent

Answer 31

Electron donor

Question 32

Disproportionation

Answer 32

Oxidation and reduction of the same element in the same reaction.

Question 33

Strong acid/base

Answer 33

Fully dissociates in solution

Question 34

Weak acid/base

Answer 34

Partially dissociates in solution

Question 35

Molarity

Answer 35

Concentration in mol dm-3 expressed using M.

Question 36

Concentration

Answer 36

Number of moles present in a stated volume.

Question 37

Standard solution

Answer 37

A solution for which the concentration is known.

Question 38

Ionic Bonding

Answer 38

The electrostatic attraction between oppositely charged ions formed by electron transfer.

Question 39

Orbital

Answer 39

A region within an atom that can hold up to two electrons with opposite spins.

Question 40

Lone pair

Answer 40

A pair of unshared electrons in the outer shell of an atom.