S C I E N C E

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Modified In-School Off-School Approach Modules (MISOSA)

Distance Education for Elementary Schools

SELF-INSTRUCTIONAL MATERIALS

CHEMICAL CHANGE

Department of Education

BUREAU OF ELEMENTARY EDUCATION 2nd Floor Bonifacio Building DepEd Complex, Meralco Avenue Pasig City

Revised 2010 by the Learning Resource Management and Development System (LRMDS),

DepEd - Division of Negros Occidental under the Strengthening the Implementation of Basic Education

in Selected Provinces in the Visayas (STRIVE).

This edition has been revised with permission for online distribution through the Learning Resource Management Development System (LRMDS) Portal (http://lrmds.deped.gov.ph/) under Project STRIVE for BESRA, a project supported by AusAID.

Section 9 of Presidential Decree No. 49 provides: “No copyright shall subsist in any work of the Government of the Republic of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit.” This material was originally produced by the Bureau of Elementary Education of the Department of Education, Republic of the Philippines.

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Do you still remember what physical change is? Let us find it out. You may answer now the exercises below. A. Put a check mark ( ) if the situation shows physical change and a cross mark (x) if not. Write the answer in your notebook.

1. Cutting a piece of cloth. 2. Water freezing to form snow. 3. Melting gold to produce gold bars 4. Gas evaporating at the gas station 5. Lighting a match

At the end of this lesson, you will be able to:

show how chemical change takes place in materials

observe that a new material is formed when chemical change takes place

Observe that the product of chemical change cannot be brought back to its

original form

Try to

Recall

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B. IN OR OUT! Write IN if the illustration show change in the original material and OUT if not.

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What is your favorite fruit? Did the you know that ripening of fruits undergo a kind of change called chemical change? Do the activities to know the other ways by which chemical change happen. Activity 1 What you need: decayed wood or plant (Options: any rotten food, moldy bread) rusty nail or any rusty object

scratch paper matchstick metal dust pan small pot or pan stove or candle 2 tablespoon sugar dissolve in 1 tablespoon water Tablespoon

What to do:

1. Observe the decayed wood, rotten food, moldy bread and the rusty nail. 2. Burn the paper in the metal dust pan. 3. Put the dissolved sugar in the pot and heat on stove or candle. Taste it.

Questions: What are the materials used? What did you do to each material? Did chemical change take place? Why?

Write your answer in a table like the one below:

Material How it undergoes Chemical Change

nail Corrosion or

bread fermentation

food Rotting or

paper Combustion or

sugar

Exploration Time

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Activity 2 What you need:

nail

¼ cup vinegar

glass bottle with ¼ water

metal dust pan

matchsticks

¼ piece of newspaper

plate

raw food like egg, seafood, etc.

pot half-filled with water

raw egg

plastic bag

any unripe fruit like guava or banana

What to do:

1. Put a nail in the bottle with water and vinegar. Let it stay for a week. Take note of the changes.

2. Let the raw food or any seafood stay on a plate for a week. Observe what happens.

3. Boil the egg on a pot. (Ask the help of your older sister or brother) 4. Burn the newspaper or a metal dust pan. (Ask the help of your older sister or

brother) 5. Put an unripe fruit like guava in a plastic bag for 3 days and observe.

Questions:

What are the original materials used in the experiment? What happened to the nail after soaking it in vinegar for a week? What happened to the egg after cooking? What happened to the paper after burning? After wrapping the unripe fruit for 3 days, what happened? Did chemical change happen? How?

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READ AND LEARN MORE I LEARNED THAT: In a chemical change, properties of materials change. Materials that undergo chemical change cannot be brought back to their

original form. Chemical change takes place through corrosion, fermentation, decomposition and cooking.

A. Write C if the situation shows chemical change and NC if the situation does not show chemical change. Write the answer in your notebook.

1. moldy bread 2. vegetable salad 3. vinegar-making 4. wood furniture 5. hot charcoal 6. rusty doorknob

Apply It

In a chemical change, the physical properties are changed and a new substance and material is formed. It takes when a substance is burned, corroded, decayed or rotten, fermented, ripened or cooked. Yeast (a very small fungus) and bacteria help in decomposition or fermentation with the help of oxygen. Corrosion (rusting) happens when oxygen acts on metal like nail while combustion (kam.bus’chan) or burning happens when oxygen reacts with a substance. Cooking makes raw food edible. When paper burns, ash is produced together with heat and light. Rust is the product of corrosion

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B. Your window has grills. What will you suggest so that they will not get rusty C. There is left-over food. What will you do so it will not spoil easily? A. Copy the situation that tells a chemical change.

1. spoiled menudo 2. corroded steel 3. burned meat 4. cooked pancit

5. decayed wood 6. ground pork 7. ripened mango 8. decomposing rat

B. Make a table like the one below. Complete the information needed.

Original Material How it undergoes chemical change

Product

1. pork Cooking Adobo or sinigang

2. steel r s ting __ __ __ __

3. wood r- ing __ __ __

4. melon Yeast + ________ oxygen Spoiled food

5. grapes _____ + ______ oxygen Wine

6. chicken C _ o _ ing

Congratulations for a job well done! Keep up the good work. Now you’re ready to move on to the next module.

Test Yourself