Unit 3 of 5

Unit 3: Reactions and Stoichiometry

Study guide for CLEP CLEP ChemistryUnit 3: Reactions and Stoichiometry. Practice questions, key concepts, and exam tips.

105

Practice Questions

45

Flashcards

6

Key Topics

Key Concepts to Study

balancing equations
limiting reagents
mole conversions
reaction types
organic functional groups
isomerism (structural and stereo)

Sample Practice Questions

Try these 5 questions from this unit. Sign up for full access to all 105.

Q1MEDIUM

What type of reaction occurs between AgNO3 and NaCl?

A.

Precipitation reaction

B.

Acid-base reaction

C.

Oxidation-reduction reaction

D.

Synthesis reaction

E.

Decomposition reaction

Show Answer

Answer: APrecipitation reaction is correct because AgNO3 and NaCl form a precipitate of AgCl.

Q2HARD

What is the decomposition of H2O2 by MnO2?

A.

Thermal decomposition

B.

Electrolytic decomposition

C.

Photolytic decomposition

D.

Hydrolytic decomposition

E.

Catalytic decomposition

Show Answer

Answer: ECatalytic decomposition is correct because a catalyst speeds up reaction.

Q3MEDIUM

If 50 mL of 0.2 M HCl is mixed with 50 mL of 0.2 M NaOH, what is the resulting concentration of NaCl?

A.

0.05 M

B.

0.5 M

C.

0.1 M

D.

0.2 M

E.

0.4 M

Show Answer

Answer: C0.1 is correct because HCl and NaOH react in a 1:1 ratio, so the number of moles of NaCl formed will be equal to the number of moles of either reactant, which is 0.2 M * 0.05 L = 0.01 mol, and the total volume is 100 mL or 0.1 L, so the concentration is 0.01/0.1 = 0.1 M.

Q4MEDIUM

What type of reaction occurs when silver nitrate is added to sodium chloride?

A.

Acid-base reaction

B.

Oxidation-reduction reaction

C.

Neutralization reaction

D.

Combustion reaction

E.

Precipitation reaction

Show Answer

Answer: EPrecipitation reaction is correct because the reaction forms a solid precipitate of silver chloride.

Q5HARD

A reaction mechanism with two steps has the following rate constants: k1 = 0.1 s1s^{-1} and k2 = 0.05 s1s^{-1}. Which step is the rate-determining step?

A.

step 1

B.

cannot be determined

C.

both steps

D.

step 2

E.

neither step

Show Answer

Answer: Dstep 2 is correct because the rate-determining step is the slowest step in the reaction mechanism, and since k2 (0.05 s^-1) is less than k1 (0.1 s^-1), step 2 is the slowest step.

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Study Tips for Unit 3: Reactions and Stoichiometry

  • Focus on understanding concepts, not memorizing facts — CLEP tests application
  • Practice with timed questions to build exam-day speed
  • Review explanations for wrong answers — they reveal common misconceptions
  • Use flashcards for key terms, practice questions for deeper understanding

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