CHEM 1411
NAME:
FIRST PRACTICE EXAM (CHAPTERS 1- 3)
SCORE:
PART 1 – Multiple Choice
_ _ _1. If 0.274 moles of a substance weighs 62.5 g, what is the molar mass of the substance, in
units of g/mol?
A) 2.28  102 g/mol
B) 1.71  101 g/mol
C)
4.38  10-3 g/mol
D) 2.17  102 g/mol
E) none of these
_ _ _2. Determine the number of moles of aluminum in 96.7 g of Al.
A) 0.279 mol
B) 3.58 mol
C) 7.43 mol
23
D) 4.21 mol
E) 6.02  10 mol
_ _ _3. What is the molar mass of acetaminophen, C8H9NO2?
A) 43 g/mol
B) 76 g/mol
C) 151 g/mol
D) 162 g/mol
E) 125 g/mol
_ _ _ 4. How many carbon atoms are there in 10 lbs of sugar, C12H22O11?
A) 9.6  1025 atoms
B) 8.0  1024 atoms
C) 159 atoms
D) 4.21 atoms
E) 342 atoms
_ _ _5. What is the coefficient of H2O when the following equation is properly balanced with the
smallest set of whole numbers?
___ Al4C3 + ___ H2O  ___ Al(OH)3 + ___ CH4
A) 3
B) 4
C) 6
D) 12
E) 24
_ _ _ 5. How many neutrons are there in an atom of lead whose mass number is 208?
A) 82
B) 126
C) 208
D) 290
E) none of them
_ _ _6. An aluminum ion, Al3+, has:
A) 13 protons and 13 electrons
B) 27 protons and 24 electrons
C) 16 protons and 13 electrons
D) 13 protons and 10 electrons
E) 10 protons and 13 electrons
_ _ _7. Which of these pairs of elements would be most likely to form an ionic compound?
A) P and Br
B) Cu and K
C) C and O
D) O and Zn
E) Al and Rb
_ _ _8. What is the formula for the ionic compound formed by calcium and selenium?
A) CaSe
B) Ca2Se
C) CaSe2
D) Ca3Se
E) CaSe3
_ _ _9. The correct name for NH4NO3 is
A) ammonium nitrate.
B) ammonium nitrogen trioxide.
C) ammonia nitrogen oxide.
D) hydrogen nitrogen oxide.
E) hydrogen nitrate.
_ _ _ 10. Condensation refers to which conversion?
A) solid  gas
B) solid  liquid
D) gas  solid
E) liquid  gas
C) gas  liquid
_ _ _ 11. The SI prefixes giga and micro represent, respectively:
A) 10-9 and 10-6.
B) 106 and 10-3.
C) 103 and 10-3.
9
-6
-9
-3
D) 10 and 10 .
E) 10 and 10 .
_ _ _ 12. Lead melts at 601.0C. What temperature is this in F?
A) 302F
B) 365F
C) 1,050F
D) 1,082F
E) 1,114F
_ _ _ 13. 2.4 km is how many millimeters?
A) 2,400 mm
B) 2.4  104 mm
D) 2.4  106 mm
E) 2.4  10-5 mm
C) 2.4  105 mm
_ _ _ 14. How many significant figures does the sum 8.5201 + 1.93 contain?
A) 1
B) 2
C) 3
D) 4
E) 5
_____ 15. Octane burns according to the following equation:
2C8H18 + 25O2  16CO2 + 18H2O
How many grams of CO2 are produced when 5.00 g of C8H18 are burned?
A) 0.351 g
B) 1.93 g
C) 15.4 g
D) 30.8 g
E) 40.0 g
_____ 16. Which of the following is not an example of a mixture?
A) iced tea
B) distilled water
C) mashed potatoes
D) vegetable soup
E) tomato juice
_____ 17. Convert 240 K and 468 K to the Celcius scale.
A) 513 oC and 741 oC
C) -18.3 oC and 108 oC
B) -59 oC and 351 oC
D) -33 oC and 195 oC
_____ 18. How many significant figures are there in the number 0.0203610 g?
A) 4
B) 5
C) 6
D) 7
_____ 19. Which of the following is an example of a physical property?
A. combustibility
B. corrosiveness
C. explosiveness
E) 8
D. density
E. A and D
_____ 20. Calculate the volume occupied by 4.50 X 102 g of gold (density = 19.3 g/cm3).
A. 23.3 cm3
B. 8.69 x 103 cm
C. 19.3 cm3
D. 450 cm3
E. 4.29x10 -2 cm3
_____ 21. Which of the following represents the greatest mass?
A) 2.0 x 103 mg
B. 10.0 dg
C. 0.0010 kg
6
12
D. 1.0 x 10 μg
E. 3.0 x 10 pg
_____ 22. The correct Stock system name for CoCl3 is
A. cobaltous chloride
D. cobalt(III) trichloride
B. cobalt trichloride
E. cobalt chloride
C. cobalt(III) chloride
_____ 23. Which of the following is not an example of an alkali metal?
A. Li
B. Cs
C. At
D. K
E. Rb
2_____ 24. The chemical name for SO3 is sulfite ion. Therefore, the chemical name of H2SO3
(aq) is
A. dihydrosulfuric acid
D. hyposulfurous acid
B. sulfurous acid
E. sulfuric acid
C. dihydrogen sulfite
_____ 25. Determine the number of moles of aluminum in 0.2154 kg of Al.
A. 1.297 × 1023 mol
D. 0.1253 mol
B. 5.811 × 1023 mol
E. 7.984 × 1023 mol
C. 7.984 mol
_____ 26. How many significant figures should you report as the sum of 8.3801 + 2.57?
A. 3
B. 5
C. 7
D. 6
E. 4
PART II- THEORY (SHOW YOUR WORK))
1a. An aluminum beverage can contains 12.0 fluid ounces of liquid. Express this volume in
microliters. (1 fl oz = 29.6 mL)
b. A piece of metal with a mass of 114 g was placed into a graduated cylinder that contained
25.00 mL of water, raising the water level to 42.50 mL. What is the density of the metal?
c. The density of mercury, the only metal to exist as liquid at room temperature, is 13.6g/cubic
cm. What is the density in pounds per cubic inch?(1lb = 454g, 1 in = 2.54cm)
2. Carry the following operations as if they were calculations of experimental results, and
express each answer in the correct units with the correct number of significant figures:
i) 7.310 km /5.70 km
ii) 4051 cm x 3.6666 cm
iii) 5.6792m +0.6m + 4.33m
iv) 3.70g – 2.9133g
3. The atomic masses of Li-6 and Li-7 are 6.0105 amu and 7.0160 amu, respectively. Calculate
the natural abundances of the two isotopes. The average atomic mass of Li is 6.941.
4. What are the empirical formulas of the compounds with the following compositions? a) 40.1
%C, 6.6% H, 53.3% O, calculate the empirical formula of the compound with molecular mass of
120g/mol.
5. A mixture of 82.40g of aluminium metal and 117.65g of oxygen is allowed to react.
a) Identify the limiting reactant.
b) Calculate the mass of the excess reactant present in the vessel when the reaction is
complete.
c) What is the percentage yield for the reaction if reaction mixture produces 120g of
aluminium oxide?
6. Assume that magnesium consists of three isotopes having the abundances and masses
given
below. According to these data, calculate the average atomic mass of magnesium.
Isotope
24-Mg
25-Mg
26-Mg
7.
Symbol
Protons
Neutrons
Electrons
Net charge
abundance
78.70%
10.13%
11.17%
mass
23.985 amu
24.986 amu
25.983 amu
54Fe2+
79
117
79
26
16
18
-3
86
136