Definitions

Question 1

What is a neutralisation reaction?

Answer 1

When an acid and a base react together to form a salt and water

Question 2

What is an acid base pair?

Answer 2

A pair of two species that transform into each other by the addition of loss of a proton.

Question 3

What is a buffer?

Answer 3

A mixture that minimises pH changes on addition of small amounts of acid or base.

Question 4

What is the standard enthalpy change of neutralisation?

Answer 4

The energy change that accompanies the neutralisation of an aqueous acid by an aqueous base to form one mole of H2O under standard conditions.

Question 5

What is lattice enthalpy?

Answer 5

The enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions.

Question 6

What is the standard enthalpy change of formation?

Answer 6

The enthalpy change that takes place when one mole of a compound is formed from its constituent elements in their standard states under standard conditions.

Question 7

What is the standard enthalpy change of atomisation?

Answer 7

The enthalpy change that takes place when one mole of gaseous atoms forms from the element in its standard state.

Question 8

What is the first ionisation energy?

Answer 8

The enthalpy change when one mole of gaseous 1+ ions is formed from its gaseous atoms.

Question 9

What is the second ionisation energy?

Answer 9

The enthalpy change when one mole of gaseous 2+ ions are formed from one mole of gaseous 1+ ions.

Question 10

What is the first electron affinity?

Answer 10

The enthalpy change when one mole of gaseous 1- ions is formed from its gaseous atoms.

Question 11

What is the second electron affinity?

Answer 11

The enthalpy change when one mole of gaseous 2- ions is formed from its gaseous 1- ions.

Question 12

What is the standard enthalpy change of solution?

Answer 12

The enthalpy change that takes place when one mole of a compound is completely dissolved in water under standard conditions.

Question 13

What is the standard enthalpy change of hydration?

Answer 13

The enthalpy change that takes place when one mole of isolated gaseous ions is dissolved in water forming one mole of aqueous ions under standard conditions.

Question 14

What is entropy?

Answer 14

The measure of disorder in a system.

Question 15

What is the standard entropy change of reaction>

Answer 15

The entropy 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 16

What is the standard electrode potential of a half cell?

Answer 16

The e.m.f of a half cell compared with a standard hydrogen half cell, measured at 298K with 1 mol/dm^3 concentrations, and at a pressure of 1 atmosphere.

Question 17

What is a transition element?

Answer 17

a d-block element that forms an ion with an incomplete d sub shell.

Question 18

What is a complex ion?

Answer 18

a transition metal ion bonded to one or more ligands by coordinate bonds.

Question 19

What is a ligand?

Answer 19

A molecule or ion that can donate a pair of electrons with the transition metal ion to form a coordinate bond.

Question 20

What is the coordination number?

Answer 20

The total number of coordinate bonds formed between a central metal ion and its ligands.

Question 21

What are stereoisomers?

Answer 21

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

Question 22

What is a bidentate ligand?

Answer 22

The ligand can donate 2 lone pairs of electrons to the central metal ion to form 2 coordinate bonds.

Question 23

What is ligand substitution?

Answer 23

A reaction in which one ligand in a complex ion is replaced by another ligand.

Question 24

What is the stability constant?

Answer 24

The equilibrium constant for an equilibrium existing between a transition metal ion surrounded by water ligands and the complex formed when the same ion has undergone a ligand substitution.