CHM 105-001 Exam 1, Sp. 2014 Answer all the questions in order in the blue book.
ID: 698289 • Letter: C
Question
CHM 105-001 Exam 1, Sp. 2014 Answer all the questions in order in the blue book. Where appropriate you must show your calculations for full credit. 1. Answer all parts: a) what is the density of lead if a sample weighing 1 635 g has a volume of 1.5 mL (b) The density of Hg is 13,6 g/em'at 20.0 'C. Ifa sample of mercury weighs 15.35 g, what is the volume in em? And; (c) Why is it necessary to state the temperature in b) above? a) Give the no. of protons, electrons and neutrons in each of the following nuclides: 2. i) Mn-55 ii) Sr-90, and b) How many protons and electrons are in i) Cu 3. Answer all parts: a) Tell what is meant by the term isotopes; and b) Draw a 'Bohr atom' diagram for each of the 3 isotopes of hydrogen 4. Write the electronic configurations for each of the following elements (AI ()s (iii) Ca 5. Write the electronic configurations for each of the following ions: (0 Al (i)s (ii) Ca 6. Give the Lewis symbols for each of the following atoms: i) N (ii) Br (ii) Cs (iv) Ga 7. Draw the Lewis electron-dot structures for each the following molecules (a) HCI (b) NH, )CH. 8 Give the systemic name for each of the following compounds: (G) KI (ii) NH (ii) HNO iv) NaHCOExplanation / Answer
(1)
(a)
Using relation:
Density = Mass/Volume
Putting values:
Density = 16.35/1.5 = 10.9 g/mL
(b)
Using relation:
Density = Mass/Volume
Putting values:
13.6 = 15.35/Volume
So,
Volume = 15.35/13.6 = 1.128 cm3
(c)
This is because density of mercury changes with temperature, and this is the principle upon which the mercury thermometers are based.
Hope this helps !