Chemistry Unit 1 Definitions

Question 0

Precipitation Reaction

Answer 0

The formation of a solid from a solution during a chemical reaction.

Question 1

Halogens

Answer 1

Group VII elements

Question 2

Oxidising Agent

Answer 2

A reagent that oxidised another species.

Question 3

Halides

Answer 3

Negative ions of group VII elements.

Question 4

Electronegativity

Answer 4

The ability of an atom to attract a bonded pair of electrons in a covalent bond towards itself.

Question 5

Disproportionation Reaction

Answer 5

The oxidation and reduction of the same element in a redox reaction.

Question 6

Reducing Agent

Answer 6

A reagent that reduces another species.

Question 7

Displacement Reaction

Answer 7

A reaction in which a more reactive element displaces a less reactive element from an aqueous solution in the latter’s ions.

Question 8

Reducing Agent

Answer 8

A species that causes reduction in another species, whilst itself is being oxidised.

Question 9

Oxidising Agent

Answer 9

A species that causes oxidation in another species, whilst itself is being reduced.

Question 10

Reduction

Answer 10

Gain of electrons or a decrease in oxidation number.

Question 11

Thermal Decomposition

Answer 11

The breaking up of a chemical substance with heat into at least two chemical substances.

Question 12

Oxidation Number or Oxidation State

Answer 12

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

Question 13

Redox Reaction

Answer 13

A reaction where both oxidation and reduction takes place.

Question 14

Oxidation

Answer 14

Loss of electrons or an increase in oxidation numbers.

Question 15

First Ionisation Energy

Answer 15

The minimum amount of energy required to remove one electron from each atom in one one mole of gaseous atoms to form 1+ ions.

Question 16

Second Ionisation Energy

Answer 16

The minimum amount of energy required to remove one electron from each ion in one mole of gaseous 1+ ions to form 2+ ions.

Question 17

Periodicity

Answer 17

Repeating patterns of properties across a period.

Question 18

Electronegativity

Answer 18

The ability of an atom to attract a bonded pair of electrons in a covalent bond towards itself.

Question 19

Alkali

Answer 19

A type of base that dissolves in water forming hydroxide (OH-)(aq) ions

Question 20

Hydrated

Answer 20

The compound in question contains water.

Question 21

Salt

Answer 21

A chemical compound formed from an acid, when a H+ ion from the acid has been replaced by a metal ion or another positive ion, such as ammonium ion NH4+.

Question 22

Base

Answer 22

A species that is a proton ( H+) acceptor.

Question 23

Anhydrous

Answer 23

The compound on question contains no water.

Question 24

Water Of Crystallisation

Answer 24

Water molecules that form an essential part of the crystalline structure of a compound.

Question 25

Acid

Answer 25

A species that is a proton ( H + ) donor.

Question 26

Hydrogen Bonding

Answer 26

A strong dipole- dipole attraction between an electron-deficient hydrogen atom on one molecule and a lone pair of electrons

Question 27

Dipole- Dipole Interactions (permanent dipole)

Answer 27

An attractive force between permanent dipoles in neighbouring polar molecules.

Question 28

Metallic Bond

Answer 28

The electrostatic attraction between positive meta ions and delocalised electrons.

Question 29

Ionic Bond

Answer 29

The electrostatic attraction between oppositely charged ions.

Question 30

Coordinate Bond

Answer 30

A shared pair of electrons which has been provided by one of the bonding atoms only.

Question 31

Van Der Waals Forces

Answer 31

Very weak attractive forces between induced dipoles in neighbouring molecules.w

Question 32

Electronegativity

Answer 32

A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.

Question 33

Covalent Bond

Answer 33

A bond formed by a shared paired of electrons.

Question 34

Molecular Formula

Answer 34

The number of atoms of each element in a molecule.

Question 35

Molar Mass

Answer 35

The mass per mole of a substance.

Question 36

Amount Of Substance

Answer 36

The quantity whose unit is the mole

Question 37

Mole

Answer 37

The amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope.

Question 38

Avagadro's Constant

Answer 38

The number of atoms per mole of the carbon 12 isotope.

Question 39

Empirical Formula

Answer 39

The simplest whole-number ratio of atoms Of each element present in a compound.

Question 40

Relative Isotopic Mass

Answer 40

The mass of an atom of an isotope compared to 1/12th the average mass of an atom of carbon-12.

Question 41

Relative Atomic Mass

Answer 41

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

Question 42

Second Ionisation Energy

Answer 42

The minimum amount of energy required to remove one electron from each ion in one mole of gaseous atoms to form 2+ ions.

Question 43

First Ionisation Energy

Answer 43

The minimum amount of energy required to remove one electron from each atom in one mole of gaseous atoms to produce 1+ ion.

Question 44

Atomic Number

Answer 44

The number of protons in the nucleus.

Question 45

Isotope

Answer 45

Atoms of an element with different number of neutrons.

Question 46

Relative Formula Mass

Answer 46

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

Question 47

Relative Molecular Mass

Answer 47

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

Question 48

Atomic Orbital

Answer 48

The region within an atom that can hold up to 2 electrons with opposite spins.

Question 49

Mass Number

Answer 49

The number of protons and neutrons in the nucleus.