Definitions - Chains, Energy & Resources

Question 1

Alicyclic

Answer 1

A hydrocarbon with carbon atoms joined together in a ring structure.

Question 2

Aliphatic

Answer 2

A hydrocarbon with carbon atoms joined together in straight or branched chains.

Question 3

Alkane

Answer 3

The homologous series with the general formula CnH2n+2

Question 4

Alkyl group

Answer 4

An alkane with a H atom removed, e.g. CH3, C2H5, C3H7; alkyl groups are often showed as “R”.

Question 5

Displayed Formula

Answer 5

A formula showing the relative positioning of all the atoms in a molecule and the bonds between them.

Question 6

Empirical formula

Answer 6

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

Question 7

Functional group

Answer 7

The part of the organic molecule responsible for its chemical reactions.

Question 8

General formula

Answer 8

The simplest algebraic formula of a member of a homologous series (e.g. CnH2n+2 for alkanes)

Question 9

Homologous series

Answer 9

A series of organic compounds with the same functional group, but with each successive member differing by a CH2.

Question 10

Hydrocarbon

Answer 10

An organic compound of hydrogen and carbon only.

Question 11

Saturated

Answer 11

A hydrocarbon with single C-C bonds only.

Question 12

Skeletal formula

Answer 12

A simplified organic formula, with H atoms removed from alkyl chains, leaving just a carbon skeleton and associated functional groups.

Question 13

Structural formula

Answer 13

A formula showing minimal detail for the arrangement of atoms in a molecule

Question 14

Structural isomerism

Answer 14

Molecules with the same molecular formula but with different structural arrangements of atoms.

Question 15

Unsaturated

Answer 15

Hydrocarbon containing C=C multiple bonds.

Question 16

Alkene

Answer 16

The homologous series with the general formula CnH2n

Question 17

Addition Polymerisation

Answer 17

The process in which unsaturated alkene molecules add on to a growing polymer chain one at a time to form a very long saturated molecular chain (the addition polymer).

Question 18

Addition reaction

Answer 18

A reaction in which a reactant is added to an unsaturated molecule to make it a saturated molecule.

Question 19

Atom economy

Answer 19

(Mr of desired product/Sum of Mr’s of all products)*100

Question 20

Cis-trans isomeriem

Answer 20

A special type of E/Z isomerism in which there is a non-hydrogen group and a hydrogen attached to each carbon of a C=C double bond.

Question 21

E/Z Isomerism

Answer 21

A type of stereoisomerism in which different groups attached to each carbon of a C=C double bond may be arranged differently in space because of the restricted rotation of the C=C double bond.

Question 22

Electrophile

Answer 22

A species capable of accepting a pair of electrons.

Question 23

Monomer

Answer 23

A small molecule that combines with many other monomers to form a polymer.

Question 24

Percentage yield

Answer 24

(actual amount, in mol, of product/theoretical amount, in mol, of product)*100%

Question 25

Pi-bond

Answer 25

The reactive part of a double bond formed above and below the plane of the bonded atoms by sideways overlap of p-orbitals.

Question 26

Polymer

Answer 26

A long molecular chain built up from monomer units.

Question 27

Repeat unit

Answer 27

A specific arrangement of atoms that occurs in the structure over and over again. Repeat units are included in brackets, outside which is the symbol n.

Question 28

Stereoisomerism

Answer 28

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

Question 29

Radical

Answer 29

Species with an unpaired electron.

Question 30

Substitution reaction

Answer 30

A reaction in which an atom or group of atoms is replaced with a different atom or group of atoms.

Question 31

Nucleophile

Answer 31

A species capable of donating a pair of electrons.

Question 32

Homolytic fission

Answer 32

The breaking of a covalent bond, with one of the bonded electrons going to each atom, forming two radicals.

Question 33

Heterolytic fission

Answer 33

The breaking of a covalent bond, with both of the bonded electrons going to one atom, forming a cation and an anion.