Question

Part II: lonic Bonds Earlier in the semester you used solubility rules to decide if a substance would dissolve in solution. Now you can explore why NaOH is soluble and Al(OH), is insoluble. The key to this concept is Lattice Energy Lattice Energy - the enthalpy required to separate a mole of a solid into its gaseous fons. Or in terms of a chemical equation, it is the value of All for the following reaction. NaCl(s) - Na" (s) Cl (3) The value of AHatice tells us something about the stability of the lonic solid. The higher the lattice energy, the more tightly the solid is held together. 1. If the lattice energy is related to the energy of attraction of oppositely charged particles, then predict how the following might influence the value of the lattice energy Magnitude of the charge of the ion Distance between the ions in the solid 11111111111111 2. Based on your answers above, explain the data in this table: Compound | NaOH Mg(OH) Al(OH)2 Lattice Energy 90 / 9 3006 kJ/mol 5627 kJ/mol Solubility 420 v/ 0.009 g/L - Og/L 3. Predict which compound would have the highest melting point. Explain. 4. Arrange the following compounds in order of decreasing lattice energy: Mg, NaCl, Na, Mgo. Explain your reasoning. CHEM 1113 - Recitation 10

Answer 1

lattice energy ~= (q1 × q2)/r2

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