CHEM ENG 1009/1009UAC/Tech Materials 1 Part A Assignment 1
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CHEM ENG 1009/1009UAC/Tech Materials 1 Part A
Assignment 1 (Individual)
Multiple Choice Section [Total = 10 Marks]
Please circle the correct answer using a pen. There is only one correct answer per question.
1. (2 Marks) Every atom consists of:
a) A nucleus composed of protons and electrons, encircled by moving neutrons.
b) Electrons arranged in a periodic structure, which periodically emit protons.
c) A neutrino composed of phonons and electrodes, encircled by moving nuclei.
d) A nucleus composed of protons and neutrons, and is encircled by moving electrons.
2. (2 Marks) Table salt, NaCl, displays which of the following types of atomic bonding:
a) Covalent
b) Ionic
c) Metallic
d) Dispersion
3. (2 Marks) Which of the following statements is true:
a) Metals are ductile due to the presence of metallic bonding.
b) Ceramics are brittle due to the presence of covalent bonding.
c) Metals are brittle due to the presence of ionic bonding.
d) Ceramics are ductile due to the presence of covalent bonding.
4. (2 Marks) Approximately how many atoms are there in 24 grams of carbon?
a) 3.0 x 1023 atoms
b) 6.0 x 1023 atoms
c) 1.2 x 1024 atoms
d) 2.4 x 1024 atoms
5. (2 Marks) A composite material…
a) …must contain exactly one metal, one ceramic and one polymer.
b) …is never observed in nature, and can only be synthesised in a laboratory.
c) …has functional and structural properties found in each of its individual components.
d) …is a combination of two or more materials that has properties that the individual components do not have by themselves.
Key Point Answer Section [Total = 20 Marks]
6. (3 Marks) You would like to be able to physically separate different materials in a scrap recycling plant. Provide a step-by-step methodology that could be used to separate a mixture of the following materials: paper, glass, brass, and cobalt.
7. (5 Marks) Read the following ABC News article, available via:https://tinyurl.com/y6faok59, and answer the following questions:
a) According to the article, how many tyres are produced each year, and how many are disposed of in landfill in Australia?
[1 Mark] b) Why is it unideal that tyres are currently disposed via landfill?
[1 Mark] c) State the three raw products that can be obtained by recycling tyres via destructive
distillation.
[1.5 Marks]
d) Briefly summarise the three steps involved during destructive distillation, which converts used tyres into the three raw products you identified in part (c).
[ 1.5 Marks]
8. (2 Marks) Barium Selenide (BaSe) exhibits predominantly ionic bonding. Which two noble gasses have the same electron configuration as the Ba2+ and the Se2- ions?
9. (3 Marks, a challenging question which requires a deep thinking and a little research) Most substances experience an increase in density upon freezing. One exception is water, which exhibits an anomalous volumetric expansion. The following table shows the density of water at a range of corresponding temperatures.
|
Temperature (ºC) |
+ 100 |
+60 |
+20 |
+ 15 |
+ 10 |
+4 |
0 |
- 10 |
|
Density (kg/m3) |
958.40 |
983.20 |
998.21 |
999.10 |
999.70 |
999.97 |
999.84 |
998.12 |
With the aid of a diagram, explain why the density of water is at its maximum value at 4ºC.
10. (7 Marks) The net potential energy between two adjacent ions, EN, may be represented by:
, where and
a) Provide a brief explanation as to why the interionic separation, r0 , is obtained when dEN/dr = 0.
[1 Mark]
b) Using the condition discussed in part (a), differentiate EN with regards to r in order to derive the following expression for the interionic separation:
[2 Marks]
c) Using the expression, you derived in part (b) and the original expression for EN, provide an equation expressing the corresponding bonding energy, E0 .
[1 Mark]
d) The interionic separation of potassium fluoride, KF, is 0.269 nm, with a corresponding bonding energy of 8.23 eV. If the value of n is 5, use the expressions you derived in part (b) and part (c) to determine constants A and B to give an explicit expression for EN in terms of r. Note: do not convert any of the units.
[3 Marks]
2022-09-05