Name: ________________________
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Chemistry 0115
Fall 2012: Midterm #1
Instructions: You have 80 minutes to complete this test. A periodic table is included with your
exam booklet. Please return it along with your midterm and the exam booklet when the allotted
time is over.
Part 1 – Multiple choice (1 mark each)
1. Which of the following is a chemical property of silver?
a. It is shiny.
b. It is malleable.
c. It melts at 961°C.
d. It has a density of 10.5g/mL
e. None of the above are chemical properties. They are all physical properties.
2. Bottled water would be classified as a(n)
a. element.
b. compound.
c. pure substance.
d. homogeneous mixture.
e. heterogeneous mixture.
3. If CHe2MiS(TrY)3 was a chemical formula, how many different elements are in
the compound?
a. 5
b. 6
c. 8
d. 11
e. There is not enough information given to determine the answer.
Use the following information to answer the next question.
During a wet lab, Dora recorded the following observations on her data sheets:
I. When drops of a yellow, clear solution are mixed with drops of another colorless,
clear solution, the resulting mixture was a purple, clear solution.
II. When a piece of chalk was hammered, it shattered into several small pieces.
III. When hydrogen peroxide and yeast are mixed in a test tube, the mixture started
bubbling and the outside of the test tube felt warm.
IV. A teaspoon of salt dissolves in 250mL of water.
4. Which of observations demonstrate evidence of a chemical reaction?
a. I and III.
b. II and IV.
c. III and IV.
d. I, III and IV.
e. All of the observations demonstrate evidence of a chemical reaction.
5. The element in period 3, group 4 is
a. actinium.
b. hafnium.
c. scandium.
d. lanthanum.
e. There is no element in period 3, group 4.
6. What would be the charge of a boron ion?
a. 3+
b. 3c. 0
d. 5e. 5+
7. What is the approximate atomic mass of an atom with 99 neutrons, 113 protons,
and 110 electrons?
a. 212
b. 209
c. 113
d. 110
e. 99
8. Which of the following values is the greatest?
a. 527 g
b. 5 x 102 mg
c. 5.3 x 10-2 g
d. 5.27 x 108 ng
e. 0.53 x 10-3 Mg
Use the following information to answer the next question.
30
Atom 1
A
32
Atom 2
15
15
A
9. The atoms shown above are both
a. radioactive.
b. cations.
c. anions.
d. isotopes.
e. ions.
10. Atoms whose outer electron shells contain eight electrons tend to
a. be isotopes and very radioactive.
b. form ionic bonds by taking electrons.
c. be stable and chemically non-reactive.
d. form ionic bonds by given away electrons.
e. form covalent bonds by sharing electrons.
Part 2 – Short answer
1. Complete all of the following conversions. Marks will be given for showing your
calculations as well as for the correct final answer.
a. 52 cm3 = __________________ mL (1 mark)
b. 0.496 hg = __________________ g (1 mark)
c. 63.80 mm = __________________ dm (1 marks)
d. 2.991 m3 = __________________ mm3 (2 marks)
e. If 760 torr = 101.325 kPa
then 9.45 kPa = __________________ torr (2 marks)
f. If 1 dash = 4 smidgens, and 1 smidgen = 0.033 tsp
then 2 tsp = __________________ dashes (2 marks)
g. What is the most appropriate way to record a mass of 0.000036 grams using
a metric prefix? In other words, what metric prefix should you use? (1 mark)
2. Answer ALL of the questions in the space provided. Each question is worth 1
mark. (8 marks total)
a. If V = 3.14 r2h, what is the formula for r?
b. Which group of elements is more reactive: the transition metals or the alkaline
earth metals? Explain why.
c. Dysprosium-162 and dysprosium-163 are naturally occurring forms of
dysprosium. Given that the atomic number of dysprosium is 66, which form of
dysprosium is less common? Explain your choice.
d. What is the cation in ammonium chloride?
e. Give an example of a metalloid.
f. Give the correct formulas for two elements that form polyatomic molecular
compounds.
g. Draw a Lewis dot (aka electron dot) diagram for radium which has an atomic
number of 88.
h. When given a chemical formula, explain how you would determine if it is a
molecular compound.
3. Complete the following table. (5 marks)
Note: If there is no information to indicate otherwise, treat the element as an
atom. Round off the atomic mass to get a whole number for an element’s mass
number.
Atom or
ion name
Symbol
# p+
# e-
42
42
# n0
Atomic
number
54
Mass
number
100
copper (II) ion
64
arsenide
33
4. For each of the following rows, identify if the compound is molecular (M), ionic (I)
or an acid (A). Then name the compound or provide the correct formula.
(18 marks)
Type of
Chemical formula
Compound name
compound
P2Cl7
actinium perchlorate
HBr
hexanitrogen tetrachloride
FeSO4 • 5H2O
sulfur triiodide
KBrO2
chromic acid
F2
cesium oxalate decahydrate
H2CO2(aq)
lead (IV) carbonate
5. The gang from Sesame Street counted the number of pennies Oscar the Grouch had
stored in his garbage can. Each member counted the pennies three times and obtained
the results shown below. The actual number of pennies in the garbage can was 3785.
o Bert: 3565; 4005; and 3762
o Elmo: 3614; 3888; and 3391
o Ernie: 3785; 3425; and 3807
o Grover: 3900; 3822; and 3824
a. Whose results are the most precise? ________________________(1 mark)
b. Oscar claims that his garbage can is made of pure iron which has a density of
7.87 x 103 kg/m3. If he is telling the truth, what should the mass of his
garbage can be if the actual volume of his garbage can is 37.853 L? (Hint:
Remember that density = mass/volume) Show all of the calculations,
including any conversions. (3 marks)
Optional bonus
If Rip Van Winkle’s alarm clock gave him 8 ½ extra minutes of sleep, how many times
would he have to hit it to sleep for 20 extra years? Assume there are 24 hours in a day,
and 365 days in a year. (Hint: Use conversion factors to solve this problem.) Marks will
be given for showing your calculations as well as for the correct final answer. (3 marks)