Mock Exam I – Chemistry 101 The exam will consist of both short answer and
problem-solving questions. This is a practice exam, with problem-solving questions
involving material that could be on the exam. It is NOT a guarantee that the real exam
will have the same problems or types of problems. In addition to this practice exam, you
should do the HW, re-do the workshops, and look at online exams.
1. The atomic ion 190Os2+ contains ___________ neutrons, ___________ protons, and
___________ electrons.
2. A student prepared a stock solution by dissolving 20.0 g of KOH in enough water to
make 150.0 mL of solution. She then took 15.0 mL of the stock solution and diluted it
with enough water to make 65.0 mL of a final solution. What is the concentration of
KOH for the final solution?
3. What is the percent mass of carbon in ethyl fluoride, C2H5F?
4. What is the formula for:
a. heptane
b. nickel (II) chloride
5. What is the name for:
a. CS2
b. Cu(SO3)
6. What is the oxidation state of the chlorine atom in perchlorate anion?
7. Determine the empirical formula of a compound that contains 36.86% N and 63.14
% O by mass.
8. Answer the following questions about the redox reaction shown below:
Cu(s) + 2 AgCl(aq) → 2 CuCl2(aq) + 2 Ag(s)
(a) What is the oxidation state of Cu on the product side of the equation?______
(b) What is the oxidation state of Cu on the product side of the equation?_________
(c) What is the oxidation state of Ag on the reactant side of the equation?__________
(c) What is the oxidizing agent?_______________
(d) Which species was reduced?________________
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Problem Solving: To get full credit, you must show a neat, thorough logical
method of solving the problem. Each number must have the appropriate unit,
and follow the rules of significant figures throughout your calculation.
9. A 0.02346 g sample of an organic compound (molar mass = 62.0 g/mol) containing
only carbon, hydrogen and oxygen was burned completely in air to produce 20.42 mg of
CO2 and 33.27 mg of H2O. What is the molecular formula of the compound?
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10. Powdered Aluminum can react with iron(III)oxide in the “thermite reaction” to form
molten iron and aluminum oxide:
2Al(s) + Fe2O3(s)
→
2 Fe(l) +
Al2O3(s)
Liquid iron is formed because the reaction releases so much energy. The liquid iron is
commonly used to weld steel railroad rails.
(a) What is the limiting reactant when a mixture of 100.0 g Al and 100.0 g Fe2O3 react?
(b) What is the theoretical yield of liquid iron?
(c) How many grams of the excess reactant remain after the reaction is complete?
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11. For each of the following reactions, write the molecular, ionic, and net ionic
equations. Also circle the appropriate category to which the reaction belongs.
(a)
Aqueous barium chloride is mixed with aqueous sodium sulfate.
Formula of barium chloride: ______________
Formula of sodium sulfate: _________
Molecular Equation:
Ionic Equation:
Net Ionic Equation:
Spectator ions (if any):
(b)
Hydrochloric acid is added to solid ammonium carbonate.
Formula of hydrochloric acid: ____________
Formula of ammonium carbonate: ___________
Molecular Equation:
Ionic Equation:
Net Ionic Equation:
Spectator ions (if any):
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12. A flask containing 450 mL of a 0.500 M HBr solution was accidentally knocked to the
floor during lab. In order to neutralize the spill, the instructor poured aqueous K2CO3
over the spill until the reaction was complete (neutralized) according to the following
equation. How many grams of the K2CO3 solution did the instructor need for the
reaction to be complete? (Hint: balance the equation before doing anything else!)
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