.
Houston Community College System
Chemistry 1413
EXAM # 1
The Periodic Table of the Chemical Elements
1
CHEM 1413 Exam #1
Name: __________________
Dr. Violeta Coarfa
Score:
Part I. Multiple choice questions. ( 3 points each)
Direction- Please write your correct choice in space provide.
1. Which one of the following units represents the largest unit of length?
a) mm b) Km c) Gm d) pm e) Mm
2. Which of the following examples illustrates a number that is correctly rounded to three
significant figures?
a) 4.05438 grams to 4.054 grams
b) 0.03954 grams to 0.040 grams
c) 109 526 grams to 109 500 grams
d) 30.0242 grams to 30.0 grams
e) 103.692 grams to 103.7 grams
3. Calculate the following to the correct number of significant figures.
23.1 x 0.0012 = _____
a) 0.1 b) 0.03 c) 0.028 d) 0.0277 e) 0.02772
4. If a can of dog food contains 44.0 oz (ounces) of dog food, how many grams would that
be? (1 lb = 454 g, 1 lb = 16 oz)
a) 624.3 g b) 1248 g c) 1250 g d) 624 g
e) 1249 g
5. What is the density (g/mL) of a sample of olive oil if 250 mL has a mass of 0.23 kg?
a) 0.00092 g/mL b) 10.9 g/mL c) 0.92 g/mL d) 57.5 g/mL
e) 0.920 g/mL
6. How many cubic decimeters equals one cubic centimeter?
a) 10-2 b) 103 c) 10-1 d) 102 e) 10-3
7. A 3.5 qt bottle of sulfuric acid contains 9.0 lb of sulfuric acid. What is the density of
sulfuric acid in g/cm3? ( 1 L = 1.057 qt; 1 lb = 454 g)
a) 1.72 b) 0.38 c) 1.23 d) 1.7 e) 1.2
2
8. The temperature in Antarctica one day was -126.9oF. What is the equivalent
temperature in oC?
a) -74.8 b) -61.9 c) -70.5 d) -88.3 e) -52.7
9. An example of kinetic energy is
a) a coiled spring.
b) running water.
c) a tree.
d) natural gas.
e) chemical energy.
10) 3.25 kcal is the same amount of energy as:
(1 cal = 4.184 J)
a) 3.25 J b) 0.777 J c) 777 J d) 13600 J
e) 13.6 J
11) One cup of kidney beans contains 15 g of protein, 1 g of fat, and 42 g of carbohydrate.
How many kilocalories, to two significant figures, does this sample contain?
(The caloric values are: 4 kcal/g for carbohydrate, 9 kcal/g for fat, and 4 kcal/g for
protein.)
a) 60 kcal b) 88 kcal c) 230 kcal d) 240 kcal
e) 520 kcal
12) Which of the following conversion factors is a measured number?
a) 2.54 cm/1 in
b) 12 in/ 1 ft
c) 16 oz/1 lb
d) 12 eggs/dozen e) 25 miles/gallon
13) If the heat of fusion for water is 80. cal/g, how many calories are needed to melt 45.0 g
of ice at 0 °C?
a) 3.6 cal b) 3.6 103cal c) 1.8 cal d) 80. cal e) 0.56 cal
14) Au is the symbol for
a) gold b) silver c) argon d) aluminum e) sodium
15) Which of the following is a characteristic of the modern periodic table?
a) A group is a horizontal row on the periodic table.
b) A period is a column on the periodic table.
c) The elements in each group have similar chemical properties.
d) The B groups contain the representative elements.
e) The A groups contain the transition elements.
3
16) Consider a neutral atom with 30 protons and 34 neutrons. The mass number of the
element is
a) 30 b) 32 c) 34 d) 64 e) 94
17) Which of the following gives the correct numbers of protons, neutrons, and electrons
in a neutral atom of 118
50 Sn ?
a) 118 protons, 50 neutrons, 118 electrons
b) 118 protons, 118 neutrons, 50 electrons
c) 50 protons, 68 neutrons, 50 electrons
d) 68 protons, 68 neutrons, 50 electrons
e) 50 protons, 50 neutrons, 50 electrons
18) The correct symbol for the isotope of potassium with 22 neutrons is
a) 1941 K
b) 1941 K
c) 1537 P
d) 1537 P
e) 1922 K
19) Which of the following is NOT true for the atoms 13N, 14N, and 15N?
a) They all have the same mass number.
b) They are isotopes.
c) They all have the same atomic number.
d) They all have 7 protons.
e) They all have 7 electrons.
20) The elements lithium, sodium, and potassium
a) are isotopes of each other.
b) are in the same period of elements.
c) have the same number of neutrons.
d) are in the same group.
e) have the same mass number.
21) What is the symbol of the element in Group 4A(14) and Period 2?
a) Be b) Mg c) Ca d) C e) Si
22) An atom is electrically neutral because:
a) the nucleus is electrically neutral
b) the charge of the protons balances the charge of the electrons
4
c) the nucleus is positive
d) it contains an equal amount of protons and neutrons
e) ions are formed.
23) The energy stored in bonds is
a) specific heat.
e) total energy
b) kinetic energy.
c) potential energy.
d) work.
24) A body of mass 2.5 kg is dropped from a height of 1m. Its kinetic energy as it touches
the ground is _______ (g=9.8 m/s2)
a) 27.0 J
b) 2.5 J
c) 24.5 J
d) 22.0 J
e) we don’t have enough information to calculate the kinetic energy when the body touches the
ground.
25) The wavelength of a radio signal broadcast at a frequency of 85 MHz is:
a) 260 cm
b) 260 m
c) 3.0 m
d) 3.5 m
e) 0.035 cm
Part II. Show all your work for complete credit. ( 5 points each)
26) The mass of the ocean is about 1.8 × 1021 kg. If the ocean contains 0.041% by mass
calcium ions, Ca2+, how many tons of Ca2+ are in the ocean? (1 ton = 2000 pounds; 1 lb =
454 g).
27) A frog's egg is about 1.5 x 103 micrometers in diameter. What is the equivalent
diameter is nanometers?
5
28) Antimony (Atomic weight 121.75) has two naturally-occurring isotopes with isotopic
weights 120.9038 and 122.9041. What is the percentage abundance of the heavier isotope?
29) The frequency at which to find a radio station broadcasting at a wavelength of 2.86 m
is:
30) Show the electronic configuration and electron (orbital) diagram for selenium and
silver elements.
Part III. Bonus Questions. (3 points each). Show your work for full credit!
1. The displacement of an auto engine is 160 in3. What is the displacement in liters?
(1 in = 2.54 cm)
6
2. If a marathon race is 26.2 miles, what is the distance in kilometers? (1 mile = 1.61
kilometer)
3. A piece of tin foil has a volume of 0.645 mm3. If the piece measures 10.0 mm by 12.5
mm, what is the thickness of the foil in mm?
7