Topic 3- Periodic table and Energy

Question 1

groups

Answer 1

vertical row of elements in the periodic table

Question 2

periods

Answer 2

horizontal row of elements in the periodic table

Question 3

periodicity

Answer 3

a repeating trend in properties of the elements across each period of the periodic table

Question 4

first ionisation energy

Answer 4

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

Question 5

successive ionisation energy

Question 6

metallic bonding

Answer 6

electrostatic attraction between positive metal ions and delocalised electrons

Question 7

reducing agent

Answer 7

reduces another species by adding electrons

Question 8

oxidising agent

Answer 8

oxidises another species by removing electrons

Question 9

disproportionation

Answer 9

a redox reaction where the same element is oxidised and reduced simultaneously

Question 10

enthalpy

Answer 10

the heat content that is stored in a chemical system

Question 11

exothermic

Answer 11

a reaction where the enthalpy of the product is smaller than the enthalpy of the reactant, resulting in heat loss to the surroundings

Question 12

endothermic

Answer 12

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 13

activation energy

Answer 13

minimum energy required to start a reaction by breaking the bonds

Question 14

standard conditions

Answer 14

a pressure of 100kPa, a stated temperature, usually 298K, and a concentration of 1 moldm^-3

Question 15

standard enthalpy change of reaction

Answer 15

the enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions and in standard states

Question 16

standard enthalpy change of formation

Answer 16

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 17

standard enthalpy change of combustion

Answer 17

the enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions and standard states

Question 18

standard enthalpy change of neutralisation

Answer 18

the enthalpy change that accompanies the reaction of an acid by a base to form one mole of water under standard conditions and in standard states

Question 19

average bond enthalpy

Answer 19

energy required to break one mole of a specified bond in a gaseous molecule

Question 20

catalyst

Answer 20

a substance that increases the rate of a chemical reaction without being used up.
Provides an alternate route with a lower activation energy.

Question 21

homogenous catalyst

Answer 21

catalyst and the reactants are in the same state

Question 22

heterogenous catalyst

Answer 22

catalyst in a different physical state to the reactants

Question 23

dynamic equilibrium

Answer 23

equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction and concentrations do not change

Question 24

le chateliers principle

Answer 24

when a system in dynamic equilibrium is subjected to a external change, the system readjusts itself to minimise the effect of the change and to restore equilibrium