CME260 F2018 Assign XG If the tesseract measures 1C G tesseract- Google Search+
ID: 715043 • Letter: C
Question
CME260 F2018 Assign XG If the tesseract measures 1C G tesseract- Google Search+ v ic blackboard 6159087-dt-content-rid-62821895 2/courses/2018 fall.cme 260 22661/CME260 F2018 Assignmes period has expired. arvel Comic Unive (a) If the tesseract measures 10 cm x 10 cm x 10 cm and is made up of entirely carbon, determine the number of carbon atoms in the tesseract. Assume the carbon in the tesseract has the same density as diamond carbon. (2 marks) (b) Natural carbon is approximately 98.9%C12, with theremainder being of thec" isotope. Ifthe tesseract is found to actually weigh 3.6 kg, determine the fraction of CD from which the tesseract is constructed. You may assume that the tesseract contains the number of atoms calculated in (a). (2 marks) Q2. (8 marks total) Types of atomic bonding. Describe both which type(s) of bonding are present in the following materials and how that type of bonding affects the properties of that material. Consider the electronegativity differences between elements where applicable to justify your comments (a) H-O in its liquid form. Why does water expand when it freezes? (2 marks) (b) Mercury. Comment on the strength of interatomic bonding in mercury (Hint: why is it a liquid at room temperature)? (2 marks) (c) Polystyrene (2 marks) (d) Copper oxide (CuO) (2 marks) Q3. (3 marks total) Polymer chemistry. Polydimethylsiloxane (PDMS) is a type of silicone that is often used in biotechnology applications. One of the interesting aspects of PDMS is that Si is the element forming its backbone as opposed to C. Draw the structure of a chain of PDMS and indicate its mer unit. Calculate the molecular weight of a PDMS chain with n-300 mer units in AMU Q4. (11 marks total) Interatomic potentials. The Lennard-Jones interatomic potential may be used toExplanation / Answer
Q2
a) Inside the water molecules covalent bonds help to bond the H and O, however in between water molecules Hydrogen bonds are prevalent. H-bonding usually exists between electronegative atoms with significant electronegative difference, i.e) it could be in between H-N or H-O etc. Water has its maximum density at 4oC, so when temperature drops below 4oC the density decreases and the distance between the H and O (between two different molecules) increases as the molecules to try to align themselves in order ready to get solidified once it attains 0oC.
b) All the electrons in the mercury are very much bound to the nuclei of the atom and they do not tend to share electrons in between atoms, hence they are held by weak forces.
c) Covalent double bonds are prevalent in polystyrene. It has irregular structure of phenyl ring followed by vinyl and double bond groups, which makes it non-crystalline. This is the reason why it is moldable at higher temperatures, as covalent double bonds become stiff when cooled down.
d) Polar covalent bonds exist in CuO as the electronegative difference between these Cu and O is 1.54
These type of compounds have lower melting points as it takes lot of energy gap to overcome the heat,
this is the reason why it is used as precursors in ceramics which are subjected to high temperatures for strengthening.