F322 Definitions

Question 1

Empirical Formula

Answer 1

Simplest whole number ration of atoms of each element in a compound.

Question 2

Molecular Formula

Answer 2

Actual number of atoms of each element in a compound,

Question 3

General Formula

Answer 3

Simplest algebraic formula of a member of a homologous series.

Question 4

Structural Formula

Answer 4

Minimal detail that shows the arrangement of atoms in a molecule.

Question 5

Displayed Formula

Answer 5

Relative positioning of atoms and the bonds between them.

Question 6

Skeletal Formula

Answer 6

Simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups.

Question 7

Homologous Series

Answer 7

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

Question 8

Functional Group

Answer 8

Group of atoms responsible for the characteristic reactions of a compound.

Question 9

Structural Isomers

Answer 9

Compounds with the same molecular formula but different structural formula.

Question 10

Stereoisomers

Answer 10

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

Question 11

E/Z Isomerism

Answer 11

Example of stereoisomerism hat has restricted rotation about the double bond and has two different groups on each carbon of the double bond.

Question 12

Cis-Trans Isomerism

Answer 12

Special case of E/Z where two of the substituent groups are the same.

Question 13

Homolytic Fission

Answer 13

Covalent bond breaks to form two radicals.

Question 14

Heterolytic Fission

Answer 14

Covalent bond breaks forming a cation and an anion.

Question 15

Atom Economy

Answer 15

Mr desired products/Mr all products x 100

Question 16

Percentage Yield

Answer 16

Mol products/mol reactants x 100

Question 17

Hydrocarbon

Answer 17

Contains hydrogen and carbon atoms only.

Question 18

Saturated

Answer 18

No C=C double bonds.

Question 19

Unsaturated

Answer 19

At least one C=C double bond.

Question 20

Radical

Answer 20

Species with unpaired electron.

Question 21

Electrophile

Answer 21

Electron pair acceptor.

Question 22

Nucleophile

Answer 22

Electron pair donor.

Question 23

Exothermic Reaction

Answer 23

A reaction in which the enthalpy of the products is greater than the enthalpy of the reactants, resulting in heat being taken in from the surroundings.

Question 24

Endothermic Reaction

Answer 24

A reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants, resulting in heat loss to the surroundings.

Question 25

Activation Energy

Answer 25

Minimum energy required to start a reaction by breaking of bonds.

Question 26

Standard Conditions

Answer 26

Pressure of 100 kPa/1 atm, temperature of 298K/25 degrees celcius and concentration of 1 moldm-3

Question 27

Enthalpy Change of Reaction

Answer 27

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.

Question 28

Enthalpy Change of Formation

Answer 28

Enthalpy change that takes place when one mole of a substance in its standard state is formed from its constituent elements in their standard states under standard conditions.

Question 29

Enthalpy Change of Combustion

Answer 29

The enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions all reactants and products being in their standard states.

Question 30

Average Bond Enthalpy

Answer 30

The average enthalpy change that takes place when breaking by homolytic fission 1 mol of a given type of bond in the molecules of a gaseous species.

Question 31

le Chatelier’s Principle

Answer 31

When a system in dynamic equilibrium is subjected to a change, the position of equilibrium will shift to minimise the change.