CHM 50
Exam 1 Review
Name
Due Tuesday 9/29/09
Exam 1 will cover chapter 1 – 3. Be sure to study all HW problems and practice problems from the textbook. Your exam
will have multiple choices, short answers and solving problems
Chapter 1
1. How can a measurement be precise but not accurate?
2. Round off each of the following numbers to three significant figures
a. 15.9998
b.
1.0080
b. 0.027255
c.
4,572
3. Complete the following table
mm
cm
m
a)
108
b)
km
7.2 x 102
c)
56.4
d)
0.250
4. A can of soda has a volume of 355 mL. What is this volume in quarts?
5. Gasoline sold as low as $0.899 per gallon in 2001. What was the cost per Liters? What did it cost to fill an 80.0L tank
in the goo d day ? In 2008, the price was $3.759 per gallon. What did it cost to fill th 80.0-L tank in 2008?
6. If a train travels at a speed of 85 mi/hr, how many yards can it travel in 37 mins?
7. Make the following temperature conversion
a. 37oC to K
b.
127K to oF
o
b. 205 K to C
d.
-25oC to K
Chapter 2
1. How do the following concepts relate and differ?
a. Element and atomic number
b. Atomic mass and atomic number
c. Mass number and atomic mass
d. Isotopes and number of protons
e. Isotopes and number of neutrons
2. An isotope of iodine has a mass number that is 10 less than two-third the mass number of an isotope of thalium.
The total mass number of the two isotope is 340. What is the mass number of each isotope? (hint : there are two
equations and two unknown)
3. Bromine is composed of 50.5% 79Br and 49.5% 81Br. The isotopic mass of 79Br is 78.92 amu and that of 81Br
is 80.92 amu. What is the mass of the element?
4. Naturally occurring Cu is 69.09% 63Cu (63.96 amu). What is the isotopic mass of 65Cu? (hint: use the atomic
mass of Cu from the periodic table to calculate the unknown )
5. Complete this table
Element
Symbol
A
Z
P
e
n
X-A
Ag-108
I
181
26
N3-
14
24
7
Chapter 3
1. Write a correct formular and provide an accurate name for each
2.
Ca2+
Mn2+
Fe3+
P3-
-OH
O2-
SO33-
BrO-
3. Write the formulas for each of the following compounds
a. Zn(IO3)2
b.
c. HNO3(aq)
d.
e. Al2(CO3)3
f.
g. KCrO4
h.
(NH4)2S
F2O
P4O10
H2Se(aq)
Cs1+
4. Write a balanced chemical equations from the following word equations. Include the physical states of each
element and compound
a. Sodium metal plus water yields hydrogen gas and an aqueous sodium hydroxide solution.
b. Potassium chlorate when heated yields potassium chlorate plus oxygen gas.
c. An aqueous phosphoric acid solution plus an aqueous calcium hydroxide solution yields water and solid
calcium phosphate.
5. A cartain alloy of copper has a density of 3.75g/ml and is 65.0% by mass copper. How many atoms are in 16.8
cm3 of this alloy?
6.
In an experiment it was found that 8.25 g of potassium combines with 6.75 g of O2. What is the empirical
formula of the compound
7. A 0.500g sample of a compound containing C, H and O was burned, and the products were collected. The
combustion reaction produced 0.733 g of CO2 and 0.302g H2O. The molar mass of the compound is 60.0 g/mol.
What is the molecular formula of the compound
8. Lysine is an amino acid which has the following elemental composition: C, H, O, N. In one experiment, 2.175 g
of lysine was combusted to produce 3.94 g of CO2 and 1.89 g H2O. In a separate experiment, 1.873 g of lysine
was burned to produce 0.436 g of NH3. The molar mass of lysine is approximately 150 g/mol. Determine the
empirical and molecular formula of lysine.