Lattice enthalpy

Question 1

What is lattice enthalpy?

Answer 1

The enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions

Question 2

Is lattice enthalpy endothermic or exothermic?

Answer 2

-exothermic as bonds are being made

Question 3

Define enthalpy change of formation?

Answer 3

• the enthalpy change that takes place when one mole of a compound is formed from its elements in standard conditions

Question 4

What is lattice enthalpy?

Answer 4

• a measure of the strength of the ionic bonding in an ionic lattice

Question 5

What is enthalpy of atomisation?

Answer 5

• The enthalpy change that takes place of the formation of one mole of gaseous atoms from its elements in standard conditions with all reactants and products in standard states

Question 6

Is the enthalpy of atomisation endothermic or exothermic?

Answer 6

• endothermic, bonds are being broken to form gaseous atoms

Question 7

What is first ionisation energy?

Answer 7

• The amount of energy required to remove one electron from each atom in one mole of an element to form of one mole of gaseous +1 ions

Question 8

Is ionisation energy endothermic or exothermic?

Answer 8

• endothermic, energy is required to overcome the nuclear attraction

Question 9

What is electron affinity?

Answer 9

• The enthalpy change that takes place when one electron is added to each atom of one mole of gaseous atoms to form one mole of gaseous -1 ions

Question 10

Is electron affinity endothermic or exothermic?

Answer 10

• The first electron affinity is exothermic, the electron is added is attracted to the nucleus
• the second electron affinity is endothermic as a second electron is being gained by an already negative ion, therefore they repel and energy is needed

Question 11

Draw a lattice enthalpy diagram.

Answer 11

• ionic lattice
• standard states
• gaseous atoms
• gaseous ions
• lattice enthalpy

Question 12

What is enthalpy of solution?

Answer 12

• The enthalpy change that takes place when one mole of a solute is dissolved in a solvent

Question 13

What is the dissolving process?

Answer 13

1. the ionic lattice breaks up into its gaseous ions
2. water molecules are attracted and surround it, enthalpy of hydration

Question 14

What is enthalpy of hydration?

Answer 14

• The enthalpy that accompanies dissolving of gaseous ions in water to form one mole of aqueous ions
  NA+(g) = Na+(aq)

Question 15

Draw an endothermic enthalpy of solution?