Question

Calculate the lattice energy of CaCl2 given that the distance between the Ca2+ and Cl- ions in the crystal lattice is 0.231 nm and the Born-Lande equation constant is 2.21 x 10^-19 J nm.

Answer 1

To calculate the lattice energy of CaCl2, we can use the Born-Lande equation:Lattice energy  U  = -A *  1 - 1/n  *  Q1 * Q2 / r Where:A = Born-Lande equation constant = 2.21 x 10^-19 J nmn = Born exponent  typically between 5 and 12, we will use 9 as an approximation for ionic compounds Q1 = charge of ion 1  Ca2+  = +2Q2 = charge of ion 2  Cl-  = -1r = distance between ions = 0.231 nmNow, we can plug in the values into the equation:U = -  2.21 x 10^-19 J nm  *  1 - 1/9  *   +2  *  -1  / 0.231 nm U = -  2.21 x 10^-19 J nm  *  8/9  *  -2 / 0.231 nm U =  2.21 x 10^-19 J nm  *  8/9  *  2 / 0.231 nm U = 1.96 x 10^-19 JThe lattice energy of CaCl2 is approximately 1.96 x 10^-19 J.