KOLEJ UNIVERSITI TEKNIKAL KEBANGSAAN MALAYSIA
Mid Term Exam
PUSAT PERKHIDMATAN AKADEMIK
Subject
:
Chemistry BACS 1232
Name
:
______________________________________
Course
:
______________________________________
Matrix Number
:
______________________________________
Time/Date
:
8:30 pm to 10.00 pm / 20th August 2003
Directions:
a) Write your name and other required information on this sheet.
b) There are 10 multiple choice questions (Section A) and 9 long answer (Section
B).
c) Answer all questions.
d) Put all your answers and calculations on this sheet.
This exam consists of 7 pages including this cover page
2
Section A [10 marks]
Circle the best answer.
1.
2.
Which of the following represents the greatest mass?
The chemical name for SO32- is sulfite ion. Therefore, the chemical name of
H2SO3 is
a)
b)
c)
d)
e)
a)
b)
c)
d)
e)
5.
9.
Cr(NO2)3
CrNO3
Cr3(NO2)2
Cr(NO3)3
Cr2(NO2)3
10.
0.14 L
0.70 L
0.80 L
1.25 L
7.20 L
Which of the following sets of quantum numbers is not allowed?
a)
b)
c)
d)
e)
17 protons, 17 neutrons, and 22 electrons
39 protons, 38 neutrons, and 39 electrons
22 protons, 17 neutrons, and 17 electrons
17 protons, 39 neutrons, and 17 electrons
17 protons, 22 neutrons, and 17 electrons
contains 6.0 x 1023 H atoms
contains 6.0 x 1023 H2 molecules
contains 1 g of H2
is equivalent to 6.02 x 1023 g of H2
None of the above
What volume of 3.0 M NaOH can be prepared using exactly 96.0 g of NaOH?
a)
b)
c)
d)
e)
3
5
7
6
4
The correct chemical formula for chromium(III) nitrite is
a)
b)
c)
d)
e)
8.
dihydrosulfuric acid.
sulfurous acid.
dihydrogen sulfite.
hyposulfurous acid.
sulfuric acid.
One mole of H2
a)
b)
c)
d)
e)
-126 and 147 K
-39 oC and 234 K
-21 oC and 252 K
39 oC and 312 K
-68 oC and 205 K
How many protons, neutrons, and electrons are there in an atom of 3917Cl
a)
b)
c)
d)
e)
7.
oC
How many significant figures should you report as the sum of 8.3801 + 2.57?
a)
b)
c)
d)
e)
4.
2.0 x 103 mg
10.0 dg
0.0010 kg
1.0 x 106 μm
3.0 x 1012 pg
At one atmosphere pressure, mercury solidifies at -38.0 oF. Express this
temperature in degrees Celcius and Kelvin.
a)
b)
c)
d)
e)
3.
6.
n = 2, l = 2, ml = 0
n = 3, l = 1, ml = -1
n = 2, l = 0, ml = 0
n = 3, l = 2, ml = 0
n = 2, l = 1, ml = 1
Which of the following species is not isoelectronic with the others?
a)
b)
c)
d)
e)
V3+
Ca2+
Ar
ClS2-
3
Section B [40 marks]
1.
Calculate the average atomic mass of bromine if naturally occuring bromine is
composed of 50.69% 79Br and 49.31% 81Br. (Estimate the relative atomic mass for
each isotope to 3 significant figures.) [4 marks]
2.
What is the mass percent of nitrogen in (NH4)2CO3 [3 marks]
3.
How many g/cm3 are equivalent to 150 lbs/ft3? [3 marks]
[1 m = 3.28 ft, 1 lbs = 453.6 g]
4
4.
For the chemical reaction,
c.
If 12.0 g of calcium are allowed to react with 12.0 g of HBr, how many
grams of hydrogen gas would be produced? [3 marks]
Ca + 2HBr  CaBr2 + H2(g),
Answer the following questions: [Molar Mass: Ca = 40, H = 1, Br = 80]
a.
How many moles of hydrogen gas are produced for each mole of
calcium consumed? [1 mark]
b.
How many grams of calcium bromide are produced if 20.0 g of Calcium
is reacted with an excess of HBr ? [3 marks]
5
5.
6.
What is the final concentration of a mixture of 1.50 liters of 1.50 M H2SO4 and
5000 mL of water? [3 marks]
a.
Theoretical Yield [4 marks]
b.
% Yield [2 marks]
Aluminium burns in bromine, producing aluminium bromide:
2Al + 3Br2  2AlBr3
When 6.0 g of aluminium was reacted with an excess of bromine, 53.3 g of
aluminium bromide was isolated. Calculate the theoretical and percent yield of
this reaction.
6
7.
8.
Depending upon the amount of fat a person has, the human body has a density of
about 0.95 g/cm3. If a person weighed 150 lbs, what would be their volume in
cm3?
[4 marks]
Tabulate all of the possible orbitals (by name, i.e. 4s) for n=4 and give the three
quantum numbers (n, l and ml ) which define each orbital. [4 marks]
9.
Write electron configurations for the following atoms:
a.
N [2 marks]
b.
F [2 marks]
c.
Br [2 marks]
Name 4s 4p
4d
4f
n
4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
l
ml
7