Module 3

Question 1

Second ionization energy

Answer 1

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

Question 2

Successive ionization energy

Answer 2

A measure of the energy required to remove each electron in turn

Question 3

Enthalpy change Delta H

Answer 3

The amount of heat released are absorbed by chemical eruption carried out. Constant pressure units = KJmol^-1

Question 4

Standard enthalpy change of reaction Delta r H theta

Answer 4

The enthalpy change that accompanies a reaction in molar quantities expressed in a chemical equation, standard conditions, all reactants and products being in their standard states

Question 5

Hess’ law

Answer 5

The enthalpy change of a reaction depends only on the initial and final states, and is independent of the route taken

Question 6

Kc expression

Answer 6

See definition sheet A2 paper 1

Question 7

Periodicity

Answer 7

Repeating trends in physical and chemical properties (1) Elements are arranged by increasing atomic (proton) number (1) in groups with similar chemical properties (1)

Question 8

s/p/d elements

Answer 8

Example: An s-block element has its highest energy electron in an s subshell

Question 9

First ionization energy

Answer 9

The energy required to remove one electron from each atom (1) in one mole of gaseous atoms to form one mole of gaseous 1+ ions (1)

Question 10

Exothermic reaction

Answer 10

Reaction where heat energy is released to the surroundings Delta H is negative

Question 11

Endothermic reaction

Answer 11

A reaction where heat energy is absorbed from the surroundings Delta H is positive

Question 12

Average bond enthalpy Delta E H theta

Answer 12

The average enthalpy change for the breaking of one mole of bonds in gaseous molecules by homolytic fission

Question 13

Standard conditions

Answer 13

Temperature equals 25° C , 298K
Pressure 1 atm, 100kPa

All solutions must have a concentration of 1.00 moldm^-3

Question 14

Standard enthalpy change of neutralization Delta neutron H theta

Answer 14

The enthalpy change that accompanies the formation of one mole of H2O from neutralization under standard conditions

Question 15

Standard enthalpy change of formation Delta f H theta

Answer 15

The enthalpy change where one mole of a compound is formed from its elements in their standard states under standard conditions

Question 16

Standard enthalpy change of combustion delta c H theta

Answer 16

The enthalpy change for complete combustion of one mole of a substance under standard conditions, all reactants and products being in their standard states

Question 17

Rate of reaction

Answer 17

The changing concentration of a reactant or a product per unit time

OR

Rate = concentration of reactant or product / time

Units = moldm^-3s^-1

Question 18

Activation energy

Answer 18

The minimum energy required to start a reaction by breaking bonds

Question 19

Heterogeneous catalysis

Answer 19

Catalysis of reaction in which the catalyst has a different physical state from the reactants

Question 20

Homogenous catalysis

Answer 20

Catalysis of a reaction in which the catalyst and the reactants are in the same physical state

Question 21

Dynamic equilibrium

Answer 21

Exists in a closed system (1) when the rate of the forward reaction is equal to the rate of the reverse reaction (1) and the concentrations of reactants and products do not change (1)

Question 22

Le Chatelier’s principle

Answer 22

When a system in dynamic equilibrium is subjected to change, the equilibrium position will shift to minimize the change