Question

Calculate the lattice energy of calcium oxide (CaO) given the following information: - The ionic charges of calcium (Ca) and oxygen (O) are +2 and -2, respectively. - The distance between the Ca and O ions in the lattice is 2.36 Å. - The Madelung constant for CaO is 1.74.

Answer 1

To calculate the lattice energy of calcium oxide  CaO , we can use the Born-Lande equation:Lattice Energy =  Madelung constant * charge of cation * charge of anion * e^2  /  4 *  *  * r where:- Madelung constant = 1.74- charge of cation  Ca  = +2- charge of anion  O  = -2- e = 1.602 x 10^-19  C  elementary charge -  = 8.854 x 10^-12  C/Nm  vacuum permittivity - r = 2.36  = 2.36 x 10^-10  m  distance between ions Now, we can plug in the values into the equation:Lattice Energy =  1.74 * 2 * 2 *  1.602 x 10^-19  ^2  /  4 *  *  8.854 x 10^-12   *  2.36 x 10^-10   Lattice Energy =  1.74 * 4 *  2.566 x 10^-38    /  4 *  *  8.854 x 10^-12   *  2.36 x 10^-10   Lattice Energy =  6.984 x 10^-38   /  9.425 x 10^-22  Lattice Energy  7.41 x 10^16 NmThe lattice energy of calcium oxide  CaO  is approximately 7.41 x 10^16 Nm.