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CHEM 10050
Fall 1995
Exam #1
Name _____________________
Soc. Sec.# _________________
Conversion factors: 1 mile = 1.61 km, 1 in. = 2.54 cm, 1 kg = 2.205 lb, 1 lb = 454 g,
1 L = 1.057 qt., 1 qt. = 946 mL, 4.184 J = 1 cal, 32 oz. = 1 qt., 4 qt. = 1 gallon,
2 pt. = 1 qt.
heat
Equations: sp. ht. = g x ∆T
Multiple Choice (3 pts. each)
____ 1) Which of the following is not a diatomic element?
a) bromine
b) hydrogen
c) carbon
d) oxygen
____ 2) Aspirin has a density of 1.40 g/cm 3. What is the volume of a tablet weighing
500 mg?
a) 0.357 cm3
b) 0.700 cm3
c) 357 cm3
d) 2.80 cm3
____ 3) Which of the following is a chemical change?
a) ice melting
c) salt dissolving
b) sulfur burning
d) water evaporating
____ 4) Which substance has definite shape and definite volume in addition to a
regular repeating three dimensional pattern at the atomic level?
a) a gas
b) an amorphous solid
c) a liquid
d) a crystalline solid
____ 5) Which of the following numbers has three significant figures?
a) 0.014
b) 0.007
c) 0.3705
d) 0.000324
____ 6) Which element has the largest radius?
a) F
b) Al
c) Cl
d) K
____ 7) Isotopes always have the same:
a) mass number
c) number of neutrons
b) atomic number
d) none of these
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____ 8) An atom of 24 Cr contains:
a) 52 protons
b) 52 electrons
c) 28 neutrons
d) 28 protons
____ 9) Which subatomic particle has a relative mass of approximately one mass unit
and a charge of 0?
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a) neutron
b) proton
c) electron
d) alpha particle
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____ 10) You are in a closed room that is filling with deadly phlogiston gas. The
specific gravity of this gas is 0.985. How should you leave?
a) walk out
b) crawl out
c) who knows?
d) stay and die!
____ 11) The prefix “micro-” used in the metric system indicates:
a) 10-3
b) 10-6
c) 10-9
d) 10-12
c) 268 K
d) none of these
____ 12) 23 °F is equivalent to:
a) 5.0 °C
b) 12 °C
____ 13) Substances that are metals are:
a) lustrous
c) good conductors of heat and electricity
b) ductile
d) all of these
____ 14) A piece of gold (Au) with a specific heat of 0.317 J/g°C requires 730 J to
change its temperature from 34.0°C to 80.0°C. What is the mass of this
piece of gold?
a) 1.06 x 104 g
c) 0.0200 g
b) 50.0 g
d) 15.9 g
____ 15) Equal amounts of heat are added to two objects of equal mass. The object
with the highest specific heat will:
a) increase in temperature the most.
c) not increase in temperature.
b) increase in temperature the least.
d) none of these
____ 16) The modern periodic table is arranged in:
a)
b)
c)
d)
order of increasing atomic weight
order of increasing number of atoms
order of increasing number of neutrons
order of increasing number of protons
____ 17) Exactly 11.4 g of Mg reacts with 15.0 g S to give the compound magnesium
sulfide (MgS). What percentage of the compound is magnesium (Mg)?
a) 50.0%
b) 56.8%
c) 43.2%
d) 31.6%
____ 18) Which of the following is a transition element?
a) Na
b) Br
c) Zn
d) Si
____ 19) _____ states that electrons cannot enter a half filled shell if an empty one is
available.
a) The Pauli Exclusion Principle
c) The Octet Rule
b) Hund’s Rule
d) Lewis Dot Rule
____ 20) Which of the following is a mixture?
a) sulfur
b) water
c) air
d) carbon dioxide
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Solve the following problems showing all work. Remember to use proper units,
significant figures and rounding.
1) Give the complete electronic configuration and electron diagram for arsenic. Also,
represent this element using a Lewis Dot Structure. (10 pts.)
2) Forgetful Freddie placed 45.0 mL of a liquid into a graduated cylinder and then
placed what appeared to be a “diamond” weighing 22.345 g into the cylinder. The
volume of the liquid in the cylinder subsequently rose to 53.1 mL. The density of
diamond is 3.500 g/mL. Did Freddie celebrate finding an authentic diamond? Show
calculations to support your answer. (5 pts.)
3) Do the following conversions using the appropriate number of significant figures
(10 pts.):
a) 23.6 pounds to milligrams
b) 26.0 miles to millimeters
c) 34 years to seconds
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d) 29.5 milliliters to microliters
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4) What dosage in grams per kilogram of body weight does a 185 lb man receive if he
takes two 500 mg tablets of erythromycin? How many 125 mg tablets should a 46 lb
child take to receive the same dose? (10 pts.)
5) Naturally occurring silver exists as two stable isotopes. 107Ag with a mass of
106.9041 amu (51.82% natural abundance) and 109Ag with a mass of 108.9047 amu
(48.18% natural abundance). Calculate the average atomic mass of silver. (5 pts.)