3.1.8 Thermodynamics

Question 1

Enthalpy change of formation (∆ f H)

Answer 1

the enthalpy change when 1 mole of a compound is formed from its elements in their standard states under standard conditions
2C + 2H -> C2H

Question 2

lattice enthalpy of formation (∆ lattice H)

Answer 2

• the enthalpy change when 1 mole of a solid ionic compound is formed from its gaseous ions under standard condition
• Ca2+ + 2Cl- > CaCl2

Question 3

Lattice enthalpy of dissociation

Answer 3

The enthalpy change when 1 mole of a solid ionic compound is dissociated into it’s gaseous ions under standard conditions; CaCl2 -> Ca2+ + 2CL-

Question 4

Enthalpy change of atomisation

Answer 4

The enthalpy change when 1 mole of gaseous atoms is made from an element in its standard state 1/2 F2 -> F

Question 5

Enthalpy change of 1st ionisation

Answer 5

• enthalpy change when 1 mole of gaseous 1+ ions are made from 1 mole of gaseous atoms Na -> Na+