Periodic Table and Energy

Question 1

Periodicity*

Answer 1

the repeating pattern of trends in physical and chemical properties which occurs across different periods in the periodic table

Question 2

First Ionisation Energy*

Answer 2

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

Question 3

Second Ionisation Energy

Answer 3

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

Question 4

Disproportionation*

Answer 4

when a species is simultaneously oxidised and reduced to form two different products

Question 5

Standard Enthalpy Change of Reaction

Answer 5

the enthalpy change when a reaction occurs in the molar quantities shown in the chemical equation under standard conditions

Question 6

Standard Enthalpy Change of Formation*

Answer 6

the enthalpy change when one mole of a compound is formed from its constituent elements in their standard states under standard conditions

Question 7

Standard Enthalpy Change of Combustion*

Answer 7

the enthalpy change when one mole of a substance is burned completely in oxygen under standard conditions

Question 8

Standard Enthalpy of Neutralisation*

Answer 8

the enthalpy change when an acid reacts with an alkali to form one mole of water under standard conditions

Question 9

Standard Conditions*

Answer 9

100kPa and 298K

Question 10

Average Bond Enthalpy

Answer 10

the energy required to break one mole of the specified bond in gaseous molecules averaged over many different compounds

Question 11

Exothermic Reaction

Answer 11

gives out energy, delta H is negative

Question 12

Endothermic Reaction

Answer 12

takes in energy, delta H is positive

Question 13

Activation Energy*

Answer 13

the minimum energy required for a reaction to occur

Question 14

Hess’ Law

Answer 14

the total enthalpy change for a reaction is always the same, no matter which chemical route is taken

Question 15

Catalyst*

Answer 15

a substance that speeds up a reaction without being used up by the overall reaction

Question 16

Homogenous Catalyst

Answer 16

a catalyst which has the same physical state as the reactants

Question 17

Heterogenous Catalyst

Answer 17

a catalyst which has a different physical state from the reactants

Question 18

Dynamic Equilibrium*

Answer 18

a dynamic equilibrium exists in a closed system when the forward and reverse reactions are both occurring at the same rate, such that there is no overall change in the concentrations of the reactants or products

Question 19

Le Chatelier’s Principle

Answer 19

when a system in dynamic equilibrium is subjected to a change, the equilibrium position will shift to minimise the change