CHE2611 - Memos, Mock Exams, Previous Tutorial Letters

CHE2611
Inorganic Chemistry II
(Theory)
MEMOS Answers and
Tutorial Letters 2018 -
2020

, CONFIDENTIAL
Page 2 of 7
MOCK EXAM
MAY/JUNE 2020


CONFIDENTIAL


Question 1
1. (a) The crystal structure of magnesium oxide, MgO is of rock salt type.
Use this fact to establish the following:


(i) The type of unit cell for MgO.


(ii) The structure of the unit cell


(iii) The stoichiometry of MgO to confirm if it’s consistent with the
structure.


(b) Using the information given below:
∆Hθ / kJ mol-1
Sublimation of Mg (s) +145
First ionization of Mg (s) +738
Second ionization of Mg (s) +1452
Dissociation of O2 (g) +498
Electron affinity of O (g) -348
Electron affinity of O- (g) +844
Enthalpy of formation of MgO (g) -602


2+ 2- 5
Radius of Mg = 0.65 Å; Radius of O = 1.76 Å; K = 1.21x10
-1
kJ.pm.mol , d* = 0.345 Å, Madelung constant A = 1.748,
23 -1 -12 -1 -1 23 -1
NA = 6.022 x 10 mol , ԑo = 8.854 10 J .C2.m 10 mol , ԑo = 8.854
12 2 1
10- J-1.C .m-