University:
Purdue University
Course:
CHM 11500 | General Chemistry
Academic year:

2003
Views:

315

Pages:

1
Author:

taipi02

Find the experimental Jattice energy of aluminшn oxideusing а Bom-Haber cycle. 1n addition to data availaЫe in your textbook, the following themюdynamic values will Ье ofuse: the second electron affinity for oxygen is779.6 kJ/nюi the suЫimation energy for Alis 330.0 kJ/nюi and the heat of fonnation of aluminшnoxide is1675.7 kJ/nюl Compare the experimental value to the calcuJated value :fromproЫem1. 2Al(s) + 3/202(9) --- Al2 O 3(s) д Ht0 = -1675.7 2Al(s) --- 2АI(9) 2S = 2(330.0) = 660.0 2АI(9) --- 2дI3+(9) 2(IР1 + IP 2 + IРз) = 2(5.986 + 18.828 + 28.447)96.4869 = 10278.0 3/202(9) --- 30(9) 3/2BDE = 3/2(493.6) = 740.4 30(9) --- 302-(9) -3(ЕА1 + ЕА 2) = -3(141.0 + -779.6) = 1915.8 2дI3+(9) + 302-(9) --- Al2 O 3(s) -E1at For the themюchemical cycle: E1at = 1675.7 + 660.0 + 10278.0 + 740.4 + 1915.8 = 15269.9 kJ/nюl There is ~2.4% difference between the experimental and theoretical values, which is quite ассерtаЫе.