Practice Questions Set # 1
MECH 221
September 2013
Note: These questions will be discussed during the tutorial sessions on September 13th and 20th. The In-Tutorial
Exercise will be on September 27th.
Question 1
From the pictures below, materials can be classified into four general categories.
a) What are these categories?
b) Based on these categories, label the blocks in the figure below to match with their suitable
densities.
1
2
3
4
c) What is the difference between composites and other types of materials? Give an example for
composite materials.
Question 2
i) What are the general physical, mechanical, electrical, magnetic and chemical properties of polymers?
ii) Briefly cite the main differences between ionic, covalent, and metallic bonding.
iii) Explain why covalently bonded materials are generally less dense than ionically or metallically
bonded ones?
Question 3
For each of the following compounds, state whether the bonding is essentially metallic, covalent, ionic,
van der Waals, or hydrogen:
(a) Ni, (b) ZrO2, (c) graphite, (d) solid Kr, (e) Si, (f) BN, (g) SiC, (h) Fe2O3, (i) MgO, (j) W, (k) H2O
within the molecules, (l) H2O between the molecules.
If ionic and covalent bonds are involved in the bonding of any of the compounds listed, calculate the
percentage ionic character in the compound.
Question 4
Calculate the force of attraction between a K+ and an O2- ion the centers of which are separated by a
distance of 1.5 nm.
Question 5
(a) Determine the relationship between the atomic radius and lattice parameter of SC, BCC and FCC
structures.
(b) Calculate the packing factor for the FCC cell
Question 6
Aluminum foil used to package food is approximately 0.001 inch thick. Assume that all of the unit cells
of the aluminum are arranged so that ao is perpendicular to the foil surface. For a 4 in. x 4 in. square of
the foil, determine the total number of unit cells in the foil.
Question 7
Determine the indices for the directions shown below.
Question 8
Determine the Miller indices for the planes shown in the following cubic unit cells.
A
D
B