This document provides an overview of key concepts related to chemical reactions, including writing and balancing chemical equations, factors that affect reaction rates such as concentration, temperature, surface area, and catalysts. It also discusses how an understanding of reaction rates can be applied to food preservation, materials production, pollution control, and corrosion prevention. A pre-assessment with multiple choice and true/false questions is included to gauge students' existing knowledge on these topics.

1. CHEMICAL
REACTION

2. Learning Competencies/Objectives
The learner should be able to:
1. Write chemical equations;
2. Apply the principles of conservation of mass to
chemical reactions;
3. Classify reactions according to the different types;
4. Identify the factors that affect reaction rates and
explain them according to collision theory; and
5. Explain how the factors affecting rates of chemical
reactions are applied in food preservation and
materials production, re control, pollution, and
corrosion.

3. Pre-Assessment
Multiple Choice. Choose the correct
answer.
1. During a chemical reaction,
A. atoms are destroyed
B. atoms are rearranged
C. elements are destroyed
D. new elements are produced

4. 2. A chemical reaction is a
process in which
A. all reactants change state
B. products change into reactants
C. the law of conservation of mass
applies
D. all of these

5. 3. What determines an atom’s
ability to undergo chemical
reactions?
A. Protons
B. Neutrons
C. innermost electrons
D. outermost electrons

6. 4. How is a chemical equation is
balanced?
A. changing subscripts
B. erasing elements as necessary
C. adding coefficients
D. adding elements as necessary

7. 5. What are the products in the
equation below? Zn + CuSO4 ----
-> ZnSO4 + Cu
A. Zn and Cu
B. Zn and CuSO4
C. ZnSO4 and Cu
D. Zn only

8. 6. What determines an atom’s
ability to undergo chemical
reactions?
A. Protons
B. Neutrons
C. innermost electrons
D. outermost electrons

9. 6 -10. Write TRUE if the statement
is correct and FALSE if incorrect
and change the underlined word/s to
make the statement correct.
6. Generally, the higher the
concentration of the reacting
substances, the faster is the reaction.

10. 7. At lower temperature,
chemical reactions occur at
slower rates.
8. The bigger the surface area of
the reactants, the faster the rate
of reaction.

11. 9. Catalysts increase the rate of
reaction by providing a reaction
pathway with a higher
activation energy.
10. The minimum energy
required to start a reaction is
called bond energy.

12. 11 - 12 Balance the following
chemical equations, then
classify the reaction according
to its type

13. 9. Catalysts increase the rate of
reaction by providing a reaction
pathway with a higher
activation energy.
10. The minimum energy
required to start a reaction is
called bond energy.

14. 13-15 Explain in concise and
brief sentences.
13. What is the function of
MnO2 in the production of
oxygen from hydrogen
peroxide in this reaction:

15. 14.Why would iron fillings rust
faster than an iron nail?
15. Enzymes are in molds and
bacteria that spoil food. Explain,
using your knowledge of factors
affecting the rate of reaction, why
food doesn’t spoil as fast when it is
refrigerated as it would at room
temperature.

16. Pre-Assessment
Multiple Choice. Choose the correct
answer.
1. During a chemical reaction,
A. atoms are destroyed
B. atoms are rearranged
C. elements are destroyed
D. new elements are produced

17. 2. A chemical reaction is a
process in which
A. all reactants change state
B. products change into reactants
C. the law of conservation of
mass applies
D. all of these

18. 3. What determines an atom’s
ability to undergo chemical
reactions?
A. Protons
B. Neutrons
C. innermost electrons
D. outermost electrons

19. 4. How is a chemical equation is
balanced?
A. changing subscripts
B. erasing elements as necessary
C. adding coefficients
D. adding elements as necessary

20. 5. What are the products in the
equation below? Zn + CuSO4 ----
-> ZnSO4 + Cu
A. Zn and Cu
B. Zn and CuSO4
C. ZnSO4 and Cu
D. Zn only

21. 6 -10. Write TRUE if the statement
is correct and FALSE if incorrect
and change the underlined word/s to
make the statement correct.
6. Generally, the higher the
concentration of the reacting
substances, the faster is the reaction.
TRUE

22. 7. At lower temperature,
chemical reactions occur at
slower rates. TRUE
8. The bigger the surface area of
the reactants, the faster the rate
of reaction. TRUE

23. 9. Catalysts increase the rate of
reaction by providing a reaction
pathway with a higher
activation energy. LOWER REACTION ENERGY (FALSE)
10. The minimum energy
required to start a reaction is
called bond energy.ACTIVATION ENERGY
(FALSE)

24. 11 - 12 Balance the following
chemical equations, then
classify the reaction according
to its type

25. 13. MnO2 ( Manganese dioxide acts
as a catalyst, it hastens the
decomposition of hydrogen
peroxide)
14.Iron lings rust faster because of
its bigger surface area the bigger the
surface area the faster the reaction
rate.

26. 15.Enzymes are biological catalysts.
Enzymes in molds and bacteria
cause food to spoil faster. Putting
food inside the refrigerator slows
down spoilage due to lower
temperature. The higher the
temperature the higher the reaction
rate. The lower the temperature the
slower the reaction rate.