CHEMICAL REACTIONS EXAMINATION QUESTIONS AND
CORRRECT ANSWER WITH EXPLANATION GRADED A+
STUDY GUIDE SOUTHERN NEW HAMPSHIRE UNIVERSITY
1. A chemical reaction is:
A. A process that forms new substances
B. A physical change only
C. A change in shape only
D. A temperature reading
Answer: A
Rationale: New substances are produced.
2. Reactants are:
A. Starting substances in a reaction
B. Final products only
C. Catalysts only
D. Solvents only
Answer: A
Rationale: They are consumed in reactions.
3. Products are:
A. Substances formed in reactions
B. Starting materials
C. Catalysts
D. Solvents
Answer: A
Rationale: Result of chemical change.
4. Law of conservation of mass states:
A. Mass is neither created nor destroyed
B. Mass increases always
C. Mass disappears
D. Mass changes randomly
Answer: A
Rationale: Total mass remains constant.
5. A balanced equation means:
A. Equal atoms on both sides
, B. Equal molecules only
C. Equal temperature
D. Equal color
Answer: A
Rationale: Atom conservation.
6. Coefficient in a chemical equation indicates:
A. Number of molecules
B. Mass only
C. Temperature
D. Pressure
Answer: A
Rationale: Quantity of substances.
7. Subscript indicates:
A. Number of atoms in molecule
B. Number of molecules
C. Temperature
D. Pressure
Answer: A
Rationale: Atomic composition.
8. Exothermic reactions:
A. Release heat
B. Absorb heat
C. Produce light only
D. Produce sound only
Answer: A
Rationale: Energy released.
9. Endothermic reactions:
A. Absorb heat
B. Release heat
C. Destroy matter
D. Produce mass
Answer: A
Rationale: Energy absorbed.
10. Activation energy is:
A. Minimum energy required to start reaction
, B. Total energy released
C. Mass of reactants
D. Volume of products
Answer: A
Rationale: Energy barrier.
11. Catalyst:
A. Speeds up reaction
B. Slows reaction always
C. Gets consumed
D. Changes products
Answer: A
Rationale: Lowers activation energy.
12. Catalyst is:
A. Not consumed in reaction
B. Always used up
C. Product only
D. Reactant only
Answer: A
Rationale: Remains unchanged.
13. Enzymes are:
A. Biological catalysts
B. Metals
C. Acids
D. Bases
Answer: A
Rationale: Protein catalysts.
14. Rate of reaction depends on:
A. Concentration
B. Color only
C. Shape only
D. Taste
Answer: A
Rationale: More particles increase collisions.
15. Increasing temperature:
A. Increases reaction rate
CORRRECT ANSWER WITH EXPLANATION GRADED A+
STUDY GUIDE SOUTHERN NEW HAMPSHIRE UNIVERSITY
1. A chemical reaction is:
A. A process that forms new substances
B. A physical change only
C. A change in shape only
D. A temperature reading
Answer: A
Rationale: New substances are produced.
2. Reactants are:
A. Starting substances in a reaction
B. Final products only
C. Catalysts only
D. Solvents only
Answer: A
Rationale: They are consumed in reactions.
3. Products are:
A. Substances formed in reactions
B. Starting materials
C. Catalysts
D. Solvents
Answer: A
Rationale: Result of chemical change.
4. Law of conservation of mass states:
A. Mass is neither created nor destroyed
B. Mass increases always
C. Mass disappears
D. Mass changes randomly
Answer: A
Rationale: Total mass remains constant.
5. A balanced equation means:
A. Equal atoms on both sides
, B. Equal molecules only
C. Equal temperature
D. Equal color
Answer: A
Rationale: Atom conservation.
6. Coefficient in a chemical equation indicates:
A. Number of molecules
B. Mass only
C. Temperature
D. Pressure
Answer: A
Rationale: Quantity of substances.
7. Subscript indicates:
A. Number of atoms in molecule
B. Number of molecules
C. Temperature
D. Pressure
Answer: A
Rationale: Atomic composition.
8. Exothermic reactions:
A. Release heat
B. Absorb heat
C. Produce light only
D. Produce sound only
Answer: A
Rationale: Energy released.
9. Endothermic reactions:
A. Absorb heat
B. Release heat
C. Destroy matter
D. Produce mass
Answer: A
Rationale: Energy absorbed.
10. Activation energy is:
A. Minimum energy required to start reaction
, B. Total energy released
C. Mass of reactants
D. Volume of products
Answer: A
Rationale: Energy barrier.
11. Catalyst:
A. Speeds up reaction
B. Slows reaction always
C. Gets consumed
D. Changes products
Answer: A
Rationale: Lowers activation energy.
12. Catalyst is:
A. Not consumed in reaction
B. Always used up
C. Product only
D. Reactant only
Answer: A
Rationale: Remains unchanged.
13. Enzymes are:
A. Biological catalysts
B. Metals
C. Acids
D. Bases
Answer: A
Rationale: Protein catalysts.
14. Rate of reaction depends on:
A. Concentration
B. Color only
C. Shape only
D. Taste
Answer: A
Rationale: More particles increase collisions.
15. Increasing temperature:
A. Increases reaction rate
