MAT E 201

Materials Science I

Assignment No.1 (13 marks)

1. Define the following terms: (a) composition, (b) structure, (c) synthesis, (d) processing,

and (e) microstructure. (1 mark)

2. Explain the difference between the terms materials science and materials engineering.

(0.5 marks)

3. What is the difference between the microstructure and the macrostructure of a material?

(2 marks)

4. Determine the mass in grams and thickness in μm of bismuth film which contains 2.5

× 1021 atoms. Consider that the Bi film is rectangular and that its surface area is 50

cm2

. Density of Bi is 9.808 g/cm3

and its relative atomic mass is 208.98 g/mol. (2

marks)

5. Density of indium is 7.286 g/cm3

, and its atomic relative mass is 114.82 g/mol. Density

of aluminum is 2.699 g/cm3

and it relative atomic mass is 26.981 g/mol. Calculate the

number of atoms per cubic centimetre for a) In and b) Al. Which element In or Al

contains more atoms per cubic centimetre? (3 marks)

6. An electronic circuit pattern with the total surface area of 3 cm2

, should be coated with

2 µm thick tungsten film. Calculate: a) how many atoms of W are required? b) how

many moles of W are required? (Ar (W) = 183.85 g/mol, ρ (W) = 19.254 g/cm3

). (3

marks)

7. Suppose an element has a valence of 2 and an atomic number of 27. Based only on

quantum numbers, how many electrons must be present in the 3d energy level? (0.5

marks)

8. Calculate the fraction of bonding of Sb2S3 that is ionic, if the electronegativity of

antimony is 2 and the electronegativity of sulphur is 2.5. (1 mark)