Born haber (Thermodynamics)

Question 1

what is enthalpy of lattice formation

Answer 1

Standard enthalpy change when 1 mole of an ionic crystal lattice is formed from its constituents ions in gaseous form

Question 2

what is enthalpy of lattice dissociation

Answer 2

Standard enthalpy change when 1 mole of an ionic crystal lattice is separated into its constituents in gaseous form

Question 3

what is the enthalpy change of formation

Answer 3

Energy transferred when 1 mile of the compound is formed from its elements under standard conditions ( 298k and 100kpa) , all reactants and products being in their standard states

Question 4

what is enthalpy of atomisation

Answer 4

Is the enthalpy change when 1 mole of gaseous atoms is formed from the element in its standard states

Question 5

what is bond dissociation enthalpy

Answer 5

Standard molar enthalpy change when one mole of a covalent bond is broken into two gaseous atoms

Question 6

what is the first ionisation enthalpy

Answer 6

Enthalpy change required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous ions with a +1 charge

Question 7

second ionisation enthalpy

Answer 7

the enthalpy change to remove 1 mole of electrons from one mole of gaseous +1 ions to produce one mole of gaseous 2+ ions

Question 8

what is the first electron affinity

Answer 8

Enthalpy change that occurs when 1 mole of gaseous atoms gain 1 mole of electrons to form 1 mole of gaseous ions with a -1 charge

Question 9

what is the second electron affinity

Answer 9

the enthalpy change when one mole of gaseous 1- ions gains one electron per ion to produce gaseous 2- ions

Question 10

what is enthalpy change

Answer 10

heat energy at constant pressure

Question 11

EQ : In terms of the forces acting on particles , suggest one reason why the first electron affinity of oxygen is an exothermic process (1)

Answer 11

There’s an attractive force between the nucleus of an O atom and an external electron

Question 12

EQ : Explain why the second ionisation energy of calcium is greater than the first ionisation energy of calcium

Answer 12

electron removed is closer to the nucleus

Question 13

EQ : Explain why the enthalpy of hydration of fluoride ions is more negative than the enthalpy of hydration of chloride ions

Question 14

what is the enthalpy of hydration of an ion

Answer 14

enthalpy change when 1 mole of a gaseous ion forms aqueous ions
e.g. Mg2+ (g) => Mg2+ (aq)

Question 15

what is an equation to help with the definition of electron affinity

Answer 15

X(g) + e- => X- (g)

Question 16

what is a perfect ionic lattice

Answer 16

• ions are in perfect sphere
• Only electrostatic attraction

Question 17

what is enthalpy change of combustion

Answer 17

The energy change when 1 mole of a substance is burned in excess oxygen with all reactants and products in their standard states

Question 18

what is enthalpy of solution

Answer 18

1 mole of an ionic compound => aqueous ions

Question 19

how do you work out enthalpy change of solution

Answer 19

Enthalpy of lattice dissociation + sum of enthalpy of hydration

Question 20

how do you work out lattice dissociation enthalpy from the value of lattice formation enthalpy

Answer 20

reverse the + or - symbol