Cork Institute of Technology
Bachelor of Science in Analytical & Pharmaceutical Chemistry - Award
(SCHEM_7_Y3)
Autumn 2008
Inorganic Chemistry
(Time: 2 Hours)
Instructions
Answer any three questions.
All questions carry equal marks.
All calculations must appear on the examination
script.
Examiners: Dr. W.G. Doherty
Dr. B.O’Regan
Useful Data:
Avogadro’s Number, N A = 6.022 × 10 23 mol −1
1 Ångstrom, 1Å= 1 × 10 −10 m = 1 × 10 −8 cm
Q1.
(a) Sketch the oxidation state free energy (Ebsworth) diagram for Chromium, assuming
[H+] = 1.0 mol dm-3. Comment on the main features of this diagram.
(10 marks)
(b)(i) “Many factors determine the oxidation state of a metal”.
Discuss this statement.
(ii)
(7 marks)
Fe(II) forms Fe(ClO4)2 but not Fe(ClO3)2 nor Fe(ClO2)2
Co(II) forms Co(ClO4)2 and Co(ClO3)2 but not Co(ClO2)2
Ni(II) forms Ni(ClO4)2, Ni(ClO3)2 and Ni(ClO2)2
Which of these three ions is the most stable? (State your reasons)
(3 marks)
Q2.
(a) Compare and contrast powder X-ray diffraction and X-ray fluorescence spectroscopy.
(10 marks)
(b) Copper forms a face-centred cubic unit cell. Its atomic radius is 1.35Å.
(i) Calculate the unit cell length.
(ii) Calculate the radius of an atom that will fit exactly into the tetrahedral
interstitial space.
(10 marks)
Q3.
Write notes on each of the following:
Q4.
(a)
Cyclosilicates.
(6 marks)
(b)
Zeolites.
(6 marks)
(c)
Glass.
(7 marks)
The molecular weight of a monoprotic organic acid (represented by HA) was determined
by the following study of its barium salt.
4.290g of the salt was converted to its free acid (HA) by reaction with 21.64mL of
0.954N H2SO4. The barium salt was known to contain 2 mol of water of hydration per
mol of Ba2+.
Write a balanced reaction for the conversion of the salt to its free acid.
How many equivalents of the barium salt are there?
What is the equivalent weight of the barium salt?
What is the molecular weight of the acid, HA?
Q5.
(20 marks)
In Crystal Field Theory, ligands interact with central metal ion to form “strong field” or
“low spin” complexes and “weak field” or high spin complexes.
For each of octahedral complexes below:
(i) Give the oxidation state of the metal
(ii) Give the electronic configuration of the bare metal
(iii) State whether they are strong field or weak field
(iv) Give the electronic configuration of the complex
(v) Determine the magnetic moment.
[Fe(CO)6]Cl2
[Cr(H2O)4Cl2]Cl
[CoF6]3(15 marks)
Give the IUPAC names for the above complexes.
(5 marks)
2
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