Enthalpy

Question 1

Lattice Enthalpy is only for …

Answer 1

Ionic compounds

Question 2

Which enthalpys are always exothermic?

Answer 2

Lattice Enthalpy, 1st Electron Affinity
Formation is usually exothermic for ionic compounds

Question 3

Which enthalpys are always endothermic?

Answer 3

Atomisation, 1st and 2nd ionisation, 2nd electron affinity

Question 4

Which enthalpys start with gaseous ions/atoms

Answer 4

Lattice Enthalpy (ions), ionisation and electron affinity (1st -atoms, 2nd - ions)

Question 5

Lattice Enthalpy Definition

Answer 5

the enthalpy change when one mole of ionic compound is formed from its gaseous ions

Question 6

Formation Definition

Answer 6

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

Question 7

Atomisation Definition

Answer 7

the enthalpy change when one mole of gaseous atoms is formed from its elements in its standard state under standard conditions

Question 8

Solution Definition

Answer 8

the enthalpy change that takes place when one mole of a compound(solute) is completely dissolved in water under standard conditions

Question 9

Hydration Definition

Answer 9

the enthalpy change that takes place when one mole of isolated gaseous ions is dissolved in water becoming one mole of aqueous ions under standard conditions

Question 10

2 steps for dissolving ionic compounds in water

Answer 10

1) ionic lattice dissociates into gaseous ions, opposite to lattice enthalpy
2) gaseous Ions are hydrated, positive ions attract oxygen (slightly negative) and negative ions attract hydrogen (slightly positive) from water