Question

Question 6 time 3+2 2+2+2 11 minutes] Calculate the lattice enthalpý of Li20 using the Kapustinskii cquation. Kapustinskiicquation : Δ1H-Mm(IZAZBI/d)(i-dil)K (K-|21 x 105 kl pm mori. d*-34,5 pm) radius of oxide (O2) 140 pm; radius of lithium ion (Li)-76 pm (b) The Bom-Mayer and Bom-Landé equations include the Madclung constant. Explain why the Madelung constant does not appear in the Kapustinskii equation. Bom forces" contribute to the lattice enthalpy. What are "Bom forces"? (d) The clectron affinity of oxygen (Og)+eOe)is a favourable exothermic process with a value of-141 kJ mor, whereas the second electron affinity (Os) + e-→ O2-w) is highly endothemic (+798 kJ mor'). Given the high energy cost associated with forming 0e, why is Li20 stable? e) In an Ellingham diagram indicating the variation of ArG with temperature for Liz0, the gradient is positive. What does the gradient represent and why is it positive?

Answer 1