Key Definitions

Question 1

Relative atomic mass.

Answer 1

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

Question 2

Relative isotopic mass.

Answer 2

The mass of an atom of an isotope, compared with 1/12th the mass of an atom of carbon-12

Question 3

Relative formula mass

Answer 3

The average mass of a molecule of formula unit compared to the mass of an atom of carbon - 12

Question 4

Substitution

Answer 4

A chemical reaction during which a functional group is replaced by another functional group.

Question 5

Saturated hydrocarbon

Answer 5

A hydrocarbon with single bonds only

Question 6

Isotope

Answer 6

Different atoms of the same element with the same number of protons and electrons but a different number of neutrons.

Question 7

Homologous series

Answer 7

A family of compounds with similar properties whose successive members differ by the addition of a CH2 group

Question 8

Functional group

Answer 8

Part of the organic molecule that is largely responsible for the molecules chemical properties.

Question 9

Aliphatic compound

Answer 9

Carbon atoms joined in branched or unbranched chains. Non aromatic.

Question 10

Aromatic compound

Answer 10

Some or all of the carbon atoms are found in a benzene ring

Question 11

Alicyclic compound

Answer 11

Carbon atoms joined to each other in a ring structure with or without branches.

Question 12

Alkyl group

Answer 12

A group containing carbon and hydrogen only and branched from the parent Alkane chain

Question 13

Saturated compound

Answer 13

A compound containing only single carbon bonds

Question 14

Unsaturated

Answer 14

A compound containing at least one double or triple carbon -carbon bond.

Question 15

Radical

Answer 15

A reactive atom or group of atoms with an unpaired electron.

Question 16

Sterioisomerism

Answer 16

The same functional group but different arrangement of atoms in space.

Question 17

Markonowikoffs rule

Answer 17

A hydrogen will be added to the carbon with the most hydrogens attached to it.

Question 18

Structural isomer

Answer 18

Same molecular formula but different structural formula.

Question 19

Electrophile

Answer 19

An atom or group of atoms attracted to an electron rich centre and accepts an electron pair.

Question 20

Electronegativity

Answer 20

Ability of an atom to attract elect density towards itself in a covenant bond

Question 21

Covenant bond

Answer 21

Attraction between a shared pair of electron and the positively charged nuclei of the atoms sharing the electrons.

Question 22

Dipole

Answer 22

Separation of opposite charges

Question 23

What is an acid?

Answer 23

An acid is a substance that, in aqueous solution, releases hydrogen ions. Proton donors.

Question 24

What is the difference between an alkali and a base?

Answer 24

A base is a substance that can neutralise an acid. It accepts H+ ions. Proton acceptor.
An alkali is a base that can dissolve in water (polar). An alkali is a soluble base. It releases OH- Ions.

Question 25

How is ammonia a base?

Answer 25

(NH3) ammonia produces hydroxide ions by reacting with water. The ammonium molecule accepts hydrogen ions in a reversible reaction.

Question 26

Hydrated salt.

Answer 26

A salt that contained water as part of its structure in the crystal lattice.