Thermodynamics

• Who is the presenter of the AQA thermodynamics video?

  Chris Harris
• What is the main focus of the video on AQA thermodynamics?

  Thermodynamics R naught C
• What is the target audience for this video?

  AQA chemistry A-level students
• What type of resources does the A Lurie chemistry YouTube channel offer?

  Revision videos and whiteboard tutorials
• What is the purpose of the PowerPoint slides mentioned in the video?

  To aid in studying and revision
• What is the first topic mentioned that will be covered in the video?

  Born-Haber cycle
• Why are definitions important in the study of thermodynamics?

  They are essential for understanding cycles
• What is the enthalpy change of formation?

  Change when one mole of compound forms
• What does lattice enthalpy of formation refer to?

  Formation of solid ionic compound from gaseous ions
• What is the lattice enthalpy of dissociation?

  Change when solid ionic compound dissociates
• What is the enthalpy change of first ionization?

  Change when one mole of gaseous ions forms
• What does enthalpy change of atomization refer to?

  Change when gaseous atoms form from elements
• What is the second ionization energy?

  Change when gaseous two-plus ions form
• What is the first electron affinity?

  Change when one mole of gaseous ions forms
• What is the second electron affinity?

  Change when gaseous two-minus ions form
• What are the steps involved in the Born-Haber cycle?

  1. Start with solid ionic compound.
  2. Convert elements to gaseous state.
  3. Form gaseous ions.
  4. Combine ions to form solid ionic compound.
• How does the Born-Haber cycle relate to Hess's law?

  Both show energy is independent of the route
• What is the significance of endothermic and exothermic processes in the Born-Haber cycle?

  Endothermic requires energy, exothermic releases energy
• What is the enthalpy of atomization of chlorine?

  Energy required to form gaseous chlorine atoms
• How do you calculate lattice enthalpy using the Born-Haber cycle?

  Use known values and apply Hess's law
• What is the enthalpy change for the formation of lithium chloride?

  -409 kJ/mol
• What happens to the energy as you go up the Born-Haber cycle?

  Energy increases as you go up
• What is the relationship between the enthalpy change and the route taken in the Born-Haber cycle?

  It remains the same regardless of the route
• If the enthalpy of atomization of chlorine is 242 kJ/mol, what is the value for 1/2 Cl2?

  121 kJ/mol
• What are the key definitions needed for the Born-Haber cycle?

  • Enthalpy change of formation
  • Lattice enthalpy of formation
  • Lattice enthalpy of dissociation
  • Enthalpy change of ionization
  • Enthalpy change of atomization
  • Electron affinity
• What is the enthalpy of formation of lithium chloride?

  -409 kJ/mol
• What is the first ionization energy of lithium?

  519 kJ/mol
• Why do we divide the enthalpy of atomization of chlorine by two?

  Because we are using 1/2 Cl₂
• How do you calculate the enthalpy of atomization for half a mole of Cl₂?

  Divide 242 kJ/mol by 2
• What is the enthalpy change for converting solid lithium to gaseous lithium?

  161 kJ/mol
• What is the sign of the first ionization energy of lithium?

  Positive, as it is endothermic
• What is the first electron affinity of chlorine?

  -364 kJ/mol
• What does a negative lattice enthalpy indicate?

  It indicates an exothermic reaction
• How do you check if your lattice enthalpy calculation is correct?

  Ensure total energy change equals zero
• What is the significance of the lattice enthalpy of formation of lithium chloride?

  It shows the energy released when forming solid
• What is the lattice enthalpy of formation of lithium chloride calculated to be?

  -846 kJ/mol
• What happens when you add a second electron to an oxygen ion?

  It is an endothermic process due to repulsion
• What is the theoretical lattice enthalpy based on?

  A perfectly ionic model of ions
• Why might experimental lattice enthalpy differ from theoretical values?

  Due to covalent character in ionic compounds
• What does a higher experimental lattice enthalpy indicate?

  More covalent character in the compound