11. Bonding & Molecular Structure

Given the following information, construct a Born–Haber cycle to calculate the lattice energy of CaCl2 1s2. (LO 6.13)

(a) 2603 kJ/mol (b) 2254 kJ/mol (c) 2481 kJ/mo (d) l663 kJ/mol

List the individual steps used in constructing a Born–Haber cycle for the formation of BaI2 from the elements. Which of the steps would you expect to be exothermic?

Use data from Appendix C, Figure 7.10, and Figure 7.12 to calculate the lattice energy of RbCl.

(b) Using data from Appendix C, Figure 7.11, Figure 7.13, and the value of the second ionization energy for Ca, 1145 kJ>mol, calculate the lattice energy of CaCl2.

Given the following values for steps in the formation of CaO(s) from its elements, draw a Born–Haber cycle similar to that shown in Figure 6.7. Eea1 for O1g2 = -141 kJ/mol Eea2 for O1g2 = 745.1 kJ/mol Heat of sublimation for Ca1s2 = 178 kJ/mol Ei1 for Ca1g2 = 590 kJ/mol Ei1 for Ca1g2 = 1145 kJ/mol Bond dissociation energy for O21g2 = 498 kJ/mol Lattice energy for CaO1s2 = 3401 kJ/mol

Use the Born–Haber cycle and data from Appendix IIB, Chapter 8 and this chapter to calculate the lattice energy of KCl. (ΔHsub for potassium is 89.0 kJ>mol.)

Use the Born–Haber cycle and data from Appendix IIB and Table 9.3 to calculate the lattice energy of CaO. (ΔHsub for calcium is 178 kJ>mol; IE1 and IE2 for calcium are 590 kJ>mol and 1145 kJ>mol, respectively; EA1 and EA2 for O are -141 kJ>mol and 744 kJ>mol, respectively.)

Construct a Born–Haber cycle for the formation of the hypothetical compound NaCl2, where the sodium ion has a 2+ charge (the second ionization energy for sodium is given in Table 7.2). (a) How large would the lattice energy need to be for the formation of NaCl2 to be exothermic?

The estimated lattice energy for CsF21s2 is +2347 kJ/mol. Use the data given in Problem 6.86 to calculate an overall energy change in kilojoules per mole for the formation of CsF21s2 from its elements. Does the overall reaction absorb energy or release it? In light of your answer to Problem 6.86, which compound is more likely to form in the reaction of cesium with fluorine, CsF or CsF2?

Use the following information plus the data given in Tables 6.2 and 6.3 to calculate the second electron affinity, Eea2, of oxygen. Is the O2-ion stable in the gas phase? Why is it stable in solid MgO? Heat of sublimation for Mg1s2 = +147.7 kJ/mol Bond dissociation energy for O21g2 = +498.4 kJ/mol Eea1 for O1g2 = -141.0 kJ/mol Net energy change for formation of MgO(s) from its elements = -601.7 kJ/mol

Given the following thermodynamic data, calculate the lattice energy of cabr2(s).

Calculate the lattice formation enthalpy (lattice energy) of the lattice for mgf₂(s), in kj/mol, given the following information: