8. thermodynamics

• What is the Born-Haber cycle used for?

  To calculate lattice enthalpies
• What is the enthalpy change of formation?

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

  Enthalpy change when solid ionic compound forms
• 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 is the enthalpy change of atomization?


  Change when gaseous atoms form from elements
• What does the second ionization energy refer to?

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

  Change when one mole of gaseous ions forms
• How does the Born-Haber cycle relate to Hess's cycles?

  Both show different routes to form products
• What is the first step in forming lithium chloride in the Born-Haber cycle?

  Starting with lithium solid and chlorine gas
• What is the second electron affinity?

  Change when one mole of gaseous two-minus ions forms
• What is the enthalpy of atomization of chlorine?

  Change from 1/2 Cl2 gas to Cl gas
• What is the first ionization energy of lithium?

  Removal of an electron to form lithium plus
• What happens during the electron affinity process for chlorine?

  Chlorine gains an electron to become stable
• What is the final step in forming lithium chloride?

  Combining lithium and chloride ions in gas state
• What is the first step in forming lithium chloride from chlorine?

  Convert chlorine gas into ions
• What is the electron affinity of chlorine?

  Adding an electron to chlorine
• Why is the process of adding an electron to chlorine exothermic?

  It completes chlorine's valence shell
• How many valence electrons does chlorine have?

  Seven valence electrons
• What is the lattice enthalpy of formation?

  Energy change when forming a solid from gaseous ions
• What does the Born-Haber cycle illustrate?

  The enthalpy change is independent of the route taken
• What happens to the enthalpy change when going against the arrow in the Born-Haber cycle?

  The sign of the enthalpy change is reversed
• Why do we divide the enthalpy of atomization of chlorine by 2?

  We are using half a mole of Cl2
• What indicates an exothermic reaction in terms of enthalpy change?

  Negative enthalpy change
• What indicates an endothermic reaction in terms of enthalpy change?

  Positive enthalpy change
• What should the total value of a complete cycle in the Born-Haber cycle equal?

  Zero
• What is the second electron affinity of oxygen?

  Endothermic process
• Why is the second electron affinity of oxygen endothermic?

  Adding an electron to a negatively charged ion
• What is the significance of the lattice enthalpy in ionic compounds?

  It indicates the stability of the ionic compound
• What is the role of ionization energy in the formation of ionic compounds?

  It measures the energy needed to remove electrons
• What is the relationship between lattice enthalpy and the size of ions?

  Smaller ions typically have higher lattice enthalpy
• How does the Born-Haber cycle relate to Hess's law?

  Both show energy changes are independent of the path
• What is the significance of the negative sign in lattice enthalpy?

  It indicates energy is released when forming a solid
• What happens to the energy when forming ionic bonds?

  Energy is released
• What is the effect of increasing ionic charge on lattice enthalpy?

  Higher charge increases lattice enthalpy
• What is the relationship between lattice enthalpy and melting point?

  Higher lattice enthalpy usually means higher melting point
• What is the role of electron affinity in ionic bond formation?

  It helps stabilize the negative ion
• What is the significance of the first ionization energy in ionic compounds?

  It measures the energy needed to form cations
• How does the Born-Haber cycle help in calculating lattice enthalpy?

  It allows for systematic energy calculations
• What is the importance of understanding lattice enthalpy in chemistry?

  It helps predict the stability of ionic compounds