5.2.1 - Lattice Enpalthy

Question 1

Define enthalpy change of formation

Answer 1

The enthalpy change when 1 mole of the compound is formed from its elements under standard conditions (298K
and 100kpa),
- check to makes ure that all reactants and products being in their standard states

Question 2

Define lattice enthalpy (of formation)

Answer 2

The enthalpy change when 1 mole of ionic compounds is formed from its gaseous ions under standard states and conditions.

Question 3

Define the term enthalpy change of 1st ionisation

Answer 3

The enpalthy change required to remove one mole of electrons from one mole of gaseous atoms to form 1 mole of **made from one mole of gaseous atoms

Question 4

Define the term enthalpy change of hydration

Answer 4

The enthalpy change when 1 mole of gaseous ions forms aqueous ions

Question 5

Define the term enthalpy change of solution

Answer 5

The energy change when 1 mole of a compound dissolves in water

Question 6

Define the term enthalpy change of atomisation

Answer 6

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

Question 7

Define the term enthalpy change of first electron affinity

Answer 7

the 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 8

Define the term enthalpy change of second electron affinity

Answer 8

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

Question 9

Define the term First Ionisation enthalpy

Answer 9

the 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 10

Define the term second Ionisation enthalpy

Answer 10

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

Question 11

The strength of a enthalpy of lattice formation depends on ?

Answer 11

1. The sizes of the ions:
   - The larger the ions, the less negative the enthalpies of lattice
   formation (i.e. a weaker lattice). As the ions are larger the charges become further apart and so have a weaker electrostatic force between them.
2. The charges on the ion:
   - The bigger the charge of the ion, the greater the attraction
   between the ions so the stronger the lattice enthalpy (more
   negative values).

Question 12

General equation for the enthalpy change of solution

Answer 12

ΔH sol = ΔH
lattice +ΔH
hydration
​

Question 13

Factors affecting enthalpy of hydration

Answer 13