Integrated Science
Week 8
Competency: Classify matter in the environment in terms of their properties.
Lesson 8-1 Density of Matter
Time Frame: three periods
I.
Objectives:
At the end of the activities, the students should be able to:
1.
2.
3.
4.
5.
6.
II.
discuss why some objects sink while others float in water;
compare the densities of various objects;
compute for the densities of solids, liquids and gases;
discuss the applications of density to daily life;
manifest positive attitudes in solving daily problems; and
demonstrate cooperation in group activities.
Subject Matter
A. Topic: Density of solid, liquids and gases
Applications of density to daily life
B. References:
Rabago, Lilia M..(1997). Science and Technology I.
Araneta Avenue, Quezon City. pp.66 – 67.
C. Materials: Refer to Student Activity Sheet 8-1a and 8-1b
III.
SD Publications, Inc.
Learning Tasks (Days 1 and 2)
A. Motivation
1. Ask the students to recall the properties of matter learned the previous week.
Tell them that in today’s activity, they will study another property of matter
called density. You can demonstrate floating and sinking of objects to show
that their observation can be explained by the concept of density.
2. Ask them to recall the concepts of mass and volume. What is the difference
between these two properties?
3. Ask the students to describe the methods they have previously learned in
determining the volume of a liquid, a regular and an irregular solid.
B. Preliminary Activity
1. Prepare the materials and put in respective trays. You will use the “STATIONS
METHOD” for this activity.
2. Give instructions on how the groups will take turns in going the activities in the
“STATIONS”.
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3. Drill on laboratory safety and procedures, as follows:
Use of the beam balance and graduated cylinder
Techniques in handling materials and glassware/equipment
C.
Activity Proper
1. Ask students to perform activity on Density of Matter 8-1a. Refer to the
Student Activity Sheet 8-1a.
2. Move around and check if the students are doing the activity properly and on
the right track and every group member is busy. Check whether they are
following the safety procedures drilled on earlier.
3. Ask questions to check if they understand what they are doing.
4. The activity is good for 2 days. Its up to you to determine where you can cut
the activity. This will probably depend on the pace of your students. You can
let the students work on the density of solids today and do a short postdiscussion, then continue with the densities of liquids and gas the following
day. They will have problem-solving activity on the third day.
D.
Discussion
1. Process data from the activity. Point out the similarities and differences
observed from the data.
2. Discuss the answers to the questions found in the Student Activity Sheet.
3. Discuss the densities of some solids, liquids, and gases. Provide a set of data
for the students to compare.
E.
Generalization



Density is the amount of matter in a given volume.
Different substances have different densities.
Density can be determined by finding the mass and the volume of the objects
then using the formula D =

M
Where d = density, m = mass, v= volume.
V
Mass is expressed in grams, and volume in mL or cm 3 , therefore the unit of
density is g/cm 3 or g/mL.
The density of water is 1.0g /mL. Materials that are less dense than water
float on it. On the other hand, materials that are denser than water sink in it.
E. Valuing/Application
Knowing the concept of density is very useful in other ways:
a. It can determine the purity of substance.
b. Farmers can apply density in their work, they can tell whether certain seeds
are good or not for planting by soaking the seeds in water; those that float are
bad seeds; those that sink are good for planting.
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Save life - this is the motto of a lifeguard in a beach. Floating or sinking in water
to save a life is the greatest achievement of a lifeguard, his milestone…his
HALO!
You may stop at this point. Ask the students to prepare their report for
Activity 8-1a and read the procedure for Activity 8-1b.
F.
Assessment
1. Using the data about the densities of common substance (Refer to Science
and Technology I by Rabago pp. 77) determine whether the following are
true or false.
a.
b.
c.
d.
e.
f.
A block of aluminum will float in mercury. T
Copper will sink in gasoline. T
To float in air, a balloon should be filled with helium. T
The mass of 10 cm of gold is 56.9 g. F
Ice will float on gasoline. F
90g of vegetable oil will have a volume of 100 m L. F
2. Choose the letter of the best answer.
a.
Which of the following is ductile?
a. copper
b. marble
c. sandstone
d. paper
b. 50 mL of water has a density of 1g/cm 3 . What is the density of 25 mL
of this water (at the same temperature) ?
a. 50 g/cm 3
b. 2 g/cm 3
c.
Which of the following can be used to identify a substance ?
a. mass
b. volume
IV.
c. 1 g/cm 3
d. 25 g/cm 3
c. weight
d. density
Agreement/Assignment
1.
2.
Explain why goldsmiths can make bracelets and necklace out of metals like gold
and silver.
Find the density of a piece of concrete whose mass is 8.76 g and whose volume
is 3.07 cm 3 .
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Student Activity Sheet 8.1
Density of Matter
Activity 8-1a
Materials
small block of wood
piece of marble
oil
graduated cylinder
beam balance
ruler
balloon
basin
water
Procedure
A. Density of Solid
1.
2.
3.
4.
5.
6.
7.
Measure the length, width and height of a block of wood in cm.
Calculate the volume of the block in cm 3 .
Measure the mass of the wood in grams using the beam balance. Record your
data in the data table below.
Determine the ratio of the mass to the volume of the block of wood. The ratio is the
density of wood.
Based on the value you got in the previous step, predict whether the block of wood
will float on water or not.
Fill a basin with water. Carefully lower the block of wood along the side of the
basin. What happened to the block of wood? Does your prediction match with your
observation?
Determine the density of a piece of limestone by water displacement.
B. Density of Liquid
8.
9.
C.
Density of Gas
10.
11.
12.
13.
14.
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Get some water. Measure a volume of it similar to the volume of the block of wood
in part A. Measure the mass of the water sample. Calculate its density.
Repeat step 8 using oil instead of water. Compare its density with that of water.
Get the mass of an empty balloon.
Inflate the balloon and measure its mass again. Compare the mass of the balloon
with and without air.
Estimate the volume of air in the balloon.
Estimate the density of air.
Compare the densities of different substances in Table 8-1a.
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Table 8-1b. Densities of different substances
Substance
Cork
Hydrogen
Concrete
Ice
Iron
Balsa Wood
Lead
Oxygen
Gasoline
Density, g/cm3
0.24
0.00009
2.3
0.92
7.8
0.13
11.3
0.0014
0.68
Data
A)
Material observed
Mass (g)
Volume (cc)
Density (g/cc)
Mass (g)
Volume (cc)
Density (g/cc)
Block of wood
Water
Block of wood
in water
B)
Material observed
Water
Oil
Air
Questions
1.
2.
3.
4.
5.
6.
7.
8.
What is the density of the block of wood? Do solids have the same densities?
Compare the density of wood density with the density of water.
What happens to the block of wood when placed in water? Is your prediction correct?
Compare the densities of water and oil.
Why does oil float on water? Give other liquids that float on water
Why does balloon float on water?
Which of the substances in Table 8-1b would float in water?
Name the solids, the liquids, and the gases in Table 8-1b. Compare the densities of the
gases with those of water.
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Generalization about densities of solids, liquids and gases
III.
Learning Tasks (Day 3)
A. Motivation:



Recall density and the method of determining it.
Discuss the students’ assignment.
Demonstrate the following:
Set on the table the following materials:
1 L graduated cylinder
small strips of cartolina
Soda water
marking pen
A pea-sized stone
raisins
Pour the soda water into the graduated cylinder
Use the POE strategy as follows:
Predict:
What will happen if a raisin or a kernel of popcorn is dropped into
the liquid? How about a piece of stone?
(Students write down their answers in cartolina strips. Let them
show their answers. )
Observe: Drop a few raisins and the stone into the graduated cylinder.
(The stone sank while the raisins fell to the bottom. Some floated
at the liquid’s surface while others floated under the surface.
Explain: Students explain what they have observed.
(Stone is heavier than water that’s why it sinks; Raisin is lighter than
water that’s why it floats).
B.
Activity Proper
Review the activity performed the previous day. Recall the data obtained and the
definition formulated from the data.
Ask the question: “In what way is density related to your earlier observations?”
From the definition of density, show the formula for determining the density of a
substance. Illustrate the application of the formula with a few problems.
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For example:
a. If the density of gold is 19.3 g/ cm3, what would be its mass if it occupies
a volume is 4 cm3?
b. Calculate the density of 10 g of carbon dioxide occupying a volume of
5000 cm3.
c. Find the density of an alcohol sample having a mass of 20g and a volume
of 25 cm3 .
d. A piece of aluminum having a mass of 96.5g was dropped into a
graduated cylinder containing 50 mL of water. When aluminum was
dropped into the graduated cylinder, the water level rose to 85.0 mL.
What is the density of aluminum?
Discussion
a. Given: density = 19.3 g/cm3 gold, volume = 4 cm3
Req’d: mass
Soln: m= D/v ;
m = 19.3 g/cm3 / 4 cm3 = 77.2 g
b. Given: mass = 10 g carbon dioxide, volume = 5 000 cm3
Req’d: density
Soln: D = m/v ;
D = 10 g/ 5 000 cm3 = 0.002 g/cm3
c. Given: mass = 20 g alcohol, volume = 25 cm3
Req’d: density
Soln: D = m/v ;
D = 20 g/ 25 cm3 = 0.8 g/cm3
d. Given: mass = 96.5 g aluminum, volume = 85 – 50 = 35 mL
Req’d: density
Soln: D = m/v ;
D = 96.5 g/ 35 cm3 = 2.76 g/cm
Additional Problem
If the density of a certain plastic used to make a bracelet is 0.78 g/ cm3, what
mass would a bracelet of 4 cm3 have? Would this bracelet float or sink in water?
Why?
C.
Generalization




Density is ratio of mass per unit volume.
It is expressed in g/ cm3, g/mL, or kg/m3.
Substances differ in densities.
Generally, solids are densest while gases are least dense. Liquids are denser
than gases but less dense than solids.
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D.
Valuing/Application:



A person who cannot float in a freshwater lake can float easily in the sea.
What does this tell you about the density of the saltwater?
“Oil and water don’t mix”, is an old saying. Relate this to what you have
learned about density to explain the scientific reason for this saying.
Assume that the density of crude oil is 0.93 g/ cm3.
a. Why does the oil pose a great danger if it spills in a body of water?
b. Is the danger greater to birds and marine animals than it is to fish and
other organisms that live on the ocean bottom?
c. How is the density of oil an advantage in the clean-up?
E.
Assessment
1. A block of wood has a volume of 10 cm3 and a mass of 17 g. What is the
density of the block of wood?
a. 0.59.g/cm3
b. 7 g/cm3
c. 117 g/cm3
d. 170 g/cm3
2. A, B, and C are three immiscible liquids. When placed in a beaker, they
occupy the positions indicated below:
A
B
C
Which of the following can be concluded?
a.
b.
c.
d.
A is the densest of the three liquids.
C is the least dense of the three liquids.
B is denser than C but less dense than A.
B is denser than A but less dense than C.
3. If the volume of a boy’s body is 8 cubic meters, with a mass of 20 kg, would
he float in water? Explain your answer.
4. Fish are able to remain at a specific depth in water without much trouble.
Many fish have an organ called a swim bladder that they can fill with air and
empty at will. How does a swim bladder help a fish stay at one level of
water?
IV.
Agreement
How can a ship as big as Titanic with a mass of 46,328 tons have a density less
than 2 g/ cm3?
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Student Activity Sheet 8.1b
Density of Matter
Materials
paper
ballpen
calculator
Procedure
A.
Solve the following density problems:
1. If the density of gold is 19.3 g/ cm3, what would be its mass if it occupies a volume
is 4 cm3?
2. Calculate the density of 10 g of carbon dioxide occupying a volume of 5000 cm3.
3. Find the density of an alcohol sample having a mass of 20g and a volume of 25
cm3
4. A piece of aluminum having a mass of 96.5g was dropped into a graduated
cylinder containing 50 mL of water. When aluminum was dropped into the
graduated cylinder, the water level rose to 85.0 mL. What is the density of
aluminum?
B.
Discuss the solution to the following problems:
1. If the density of a certain plastic used to make a bracelet is 0.78 g/ cm 3, what mass
would a bracelet of 4 cm3 have? Would this bracelet float or sink in water? Why?
2. A person who cannot float in a freshwater lake can float easily in the sea. What
does this tell you about the density of the saltwater?
3. “Oil and water don’t mix”, is an old saying. Relate this to what you have learned
about density to explain the scientific reason for this saying.
4. Assume that the density of crude oil is 0.93 g/ cm3.
a. Why does the oil pose a great danger if it spills in a body of water?
b. Is the danger greater to birds and marine animals than it is to fish and other
organisms that live on the ocean bottom?
c. How is the density of oil an advantage in the clean-up?
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Integrated Science
Week 8-Cont’d
Competency: Investigate physical and chemical changes taking place in the
environment.
Lesson 8-2 Acids and Bases in Matter
Time Frame: two periods
I.
Objectives
At the end of the activities, the students should be able to:
1.
2.
3.
4.
5.
II.
prepare acid-base indicators from plants;
test the prepared indicators on different concentrations of acids and bases;
state the operational definition of acids and bases;
testing for acids and bases in commonly-used materials;
discuss the significance of knowing the characteristics of acids and bases in
relation to the environment.
Subject Matter
A. Topic: Acids and Bases in Matter
B. References: Any Integrated Science or Physical Science Textbook
C. Materials: refer to the Student Activity Sheet 8-2a and 8-2b
III.
Learning Tasks
A. Motivation
1. Bring out slices of dalanghita, green mango, and unripe sampalok. Call out 3
volunteers to come near the teacher’s table. Give a piece of dalanghita to the
first, a slice of green mango to the second, and a piece of unripe sampalok to
the third. Ask them to chew their respective fruit then ask the rest of the class
to describe their facial expressions. What seems to be the problem of the
three? What could be the reason for their unusual expressions? Ask further
questions until students relate acids to sour taste.
2. Ask the students, if acidic foods taste sour, how about basic foods? Tell them
that there are materials, other than foods. that are either acidic or basic but
they cannot be identified through tasting . Another way is through the use of
acid-base indicator. In this activity they will further differentiate acids and bases
using improvised indicator from plants.
B. Preliminary Activity
1. Gather different leaves: some groups can experiment on mayana leaves
while the other groups can use gumamela flowers. Just be sure that they use
the red variety.
2. Prepare the acids and bases before hand. Likewise check the materials
which students brought from their homes.
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3. Discuss objectives of the activity.
4. Drill on laboratory safety and procedures.
Handling corrosive chemicals (hydrochloric acid and sodium hydroxide)
Heating objects with an alcohol burner
Transferring of liquids and solids
Decanting liquids
Using glassware like beaker, graduated cylinder, droppers, stirring rod
Observing materials
C.
Activity proper
a. Depending on the number of groups, assign half of the groups to use mayana
leaves, the other half, gumamela flowers. This will show that indicators can
be prepared from colored plants. However, the darker the color of plants, the
better the extract. If there are other colored flowers in your area, you can ask
the students to conduct an investigation of these flowers. The procedure for
preparing the indicators is the same for most of the plants. They can even
revise the procedure to suit their materials.
b. The indicator extract gets spoiled if it is left for more than 5 minutes. Thus,
remind the students to add alum immediately to the extract after it is
decanted from the solution. Alum stabilizes the extract, makes the extract
lasts a little longer, particularly if it is kept in a cool place. The indicator paper
can last for a few months if stored in a clean and tightly covered bottle.
c. The lesson is good for 2 days. It may be extended to 3 if the students are
unable to get the correct color changes. Let them do Activity 8-2a today then
conduct a short post-discussion.
d. Do Activity 8-4b the following day. You can reduce the materials to be tested
if you think it will use much time. It is better that they test materials that they
use everyday like shampoo, detergents, and fruit juices. They may be fond of
drinking colas, but their fondness may be lessened if they find that colas
contain strongly acidic substances. You can ask them to test different brands
of shampoos, detergents, fruit juices, and colas to find out which are good or
bad for their health.
e. Move around and check if the students are doing the activity properly and on
the right track. See to it that every group member is busy. Check whether they
are following the safety procedures. Ask questions to check if they understand
what they are doing.
D.
Discussion
a. Process the results gathered by each group. A group member can report
orally or write on manila paper so that other groups can compare their results.
Point out similarities and differences in the results.
b. Discuss the answers to the questions in the student activity sheet. Additional
discussion may include the following:
The word acid and alkaline (older term for base) are derived form direct
sensory experience. Acid comes from the Latin word acere meaning “sour”.
All acids taste sour. Vinegar, fruit extract and juices tastes sour. Aspirin
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tastes sour if you let it stay awhile in your mouth. Its chemical name is
acetylsalicylic acid.
The word base, unlike acid, is not related to taste. All bases taste bitter.
Mustard and ampalaya taste bitter. Cough syrup and many medicines taste
bitter. Manufacturers add sugar and other flavorings to medicines to hide the
bitter taste of the active ingredients. Bases feel slippery, sometimes people
say soapy. This because they dissolve the oils from your skin and this
reduces friction between your thumb and another finger as you rub them
together. In essence the base is making soap out of you.
Acids and bases destroy each other ‘s properties to produce a new
substance, generally called salt. This type of reaction is called neutralization.
Chemists use the pH scale to express how acidic (like an acid) or basic (like
a base) a substance is. A pH value below 7 means that a substance is acidic,
and the smaller the number, the more acidic it is. A pH value above 7 means
that a substance is basic, and the larger the number, the more basic it is. The
closer the pH of a substance to zero, the more acidic it is. Conversely, the
closer the pH of a substance to 14, the more basic it is.
Indicators are used to identify acids and bases. They are large organic
molecules that change color at various pH values. The most common
acid/base indicator is litmus paper which changes color (blue or red) in the
presence of any acid or base. Most indicators have complex formulas that are
synthesized by reactions. Plant indicators like mayana and gumamela
extracts have its own colors at different pH values. These colors and
approximate pH values are:
Color changes of plant Indicator
pH
1
2 3 4 5 6
red light pink
red
increasing
acidity
7
8 9 10 11 12
blue
green
n
e
u
t
r
a
l
13
14
yellow
increasing
basicity
The coloring matter responsible for the color changes are groups of organic
substances known as anthocyanins and flavonoids. A typical anthocyanin
shows red in acid, purple in neutral, and blue in basic solution, as observed
on blueand red litmus paper. Anthocyanins and flavonoids show red in acids
but yellow in strong base as observed on mayana and gumamela extracts.
The green color is a mixture of blue and yellow. Both anthocyanins and
flavonoids are usually present in many plants.
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Importance of pH
pH and the body. Different aqueous solutions in various parts of our body
have different pH values. Stomach fluids are strongly basic due mainly to the
presence of dilute hydrochloric acid. The pH of gastric juice is about 2. Acid
conditions are needed for the digestion of proteins. Our small intestines need
alkaline liquids for the digestion of carbohydrates. Blood is almost neutral.
However, blood traveling from the heart to the lungs carries a lot of carbon
dioxide. This makes the blood weakly acidic with a pH slightly less than 7.
Our body fluids must be maintained at correct pH values in order to function
properly.
pH and the soil. The pH of soil plays an important role in the growth of
plants. It determines the availability of nutrients to plants. If the soil is too
acidic or too basic, plants usually do not grow. Most plants require a pH of 7
to 8 to grow well. Lime, a basic substance, is sometimes added to an acidic
soil to raise its pH or even neutralize it.
Common Materials
Hydrochloric Acid (4%)
Stomach Acid
Lemon Juice
Vinegar
Soft Drinks
Tomato Juice
Beer
Rainwater (Unpolluted)
Milk
Cheese
Urine, human
Cow’s milk
Saliva, human
Drinking water
Egg Whites
Blood, human
Seawater
Baking Soda
Ammonia
Milk of Magnesia
Sodium Hydroxide (4%)
E.
pH
0
1.0 – 3.0
2.2 – 2.4
2.5 – 3.0
2.0 – 4.0
4.0
4.0 – 5.0
5.0
6.0 – 6.6
4.8 – 6.4
4.8 – 8.4
6.3 – 6.6
6.5 – 7.5
5.5 – 8.0
7.6 – 8.0
7.3 – 7.5
8.3
9.0
10.0 – 11.0
10.5
13.0 – 14.0
Generalization



Indicators show the presence of an acid or base in a substance by changing
colors at different values or pH ranges.
The pH scale is used to measure the degree of acidity and basicity.
Acids and bases are found everywhere: in the homes, in schools, in the
streets.
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

F.
Acids and bases have wide applications in the arts, industry, and agriculture.
Acids and bases affect the environment.
Valuing/Application
a. Applying what they have learned, ask the students to find within and outside
the building various acid and base products. Let them work in groups. The
group that can identify the highest number of acids and bases will get
additional grade points.
b. Why do we study acids and bases?
1. Acids and bases are studied because many substances that we use daily
contain acids and bases. They are found in food (citrus fruits,
vegetables) , in cleaning materials (soap, toothpastes, cleansers).
2. Acids have applications in arts (etching), in industry (fertilizers,
explosives, dyes), transportation (batteries) and the home (baking,
preserving, cooking).
3. Bases have applications in industry (leather tanning), and agriculture
(liming soils and lakes).
4. Acids and bases affect the human body (ulcers, excess use of antacids,
stomach upset)
5. Acids affect the environment (acid rain and corrosion, acid lakes and
rivers)
G.
Assessment
1. The deep blue indicator used in the analysis of some soil samples gave the
following color changes:
Red
Blue
Green
Yellow
-
below pH 3
between pH 5 and pH 7
above pH 8
between pH 12 and pH 14
What is the change in color of the indicator if the extract from the soil
sample was found to contain a weak base?
a. deep blue to red
b. deep blue to yellow
c. deep blue to deep blue
d. deep blue to green
2. Why don’t flower pigments dissolve when they become wet with rain?
IV.
Agreement/Assignment
1. Research Project: Have students, research in groups and report on the
importance of pH levels in a public swimming pool, in soils, and a landfill site.
2. List some acids and bases and state their uses.
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Student Activity Sheet 8-2
Acids and Bases
Activity 8-2a
Materials
Any colored flowers or leaves
(e.g.red mayana leaves
red gumamela flowers)
yellow bell)
test tubes
test tube holder
stirring rod
tweezers
filter paper
muriatic acid
distilled water
sodium hydroxide solution
beam balance
10 mL graduated cylinder
4 sets petri dish
6 droppers
10 mL graduated cylinder
100 mL beakers
alcohol burner
vials with cover
scissors
calamansi extract
soap solution
labeling pen
Procedure
A. Preparing the Acid/Base Indicator
1.
2.
3.
4.
5.
Cut the leaves into pieces. Weigh about 6g of the leaves and place in a 100 mL
beaker.
Add 50 mL of water to the beaker and boil the contents for 5 min. or until the liquid
has turned reddish brown.
Carefully decant the extract into another beaker while still hot. Caution: Use cloth
to hold the hot beaker.
Immediately add a little amount of alum powder. Observe the solution. If the
solution does not turn blue, add a little more of the alum.
What do you think is the purpose of adding alum?
Transfer the indicator solution into clean vials and keep covered when not in use.
B. Preparing the Acid/Base Indicator Paper
1.
2.
C.
Cut a piece of filter paper into small several strips (1cm x 4cm).
Transfer some of the liquid indicator in a petri dish. Place some of the filter paper
strips in the petri dish and keep it immersed in the indicator for about 10 minutes.
Then carefully remove each paper strip with a tweezer and transfer into another
petri dish to dry.
Testing the Indicators with Acids and Bases
1.
Label 5 test tubes A to E and line in a test tube rack.
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2.
Fill each test tube with 5 mL of the liquids as shown in the figure below.
A
muriatic
acid
3.
B
calamansi
extract
C
distilled
water
D
soap
solution
E
sodium hydroxide
solution
Get 5 pieces of the dry paper indicator. Spread out in a petri dish as in the figure
below.
A
B
D
C
E
4.
Place 1-2 drops of the corresponding solution onto the paper indicator. Note down
the changes in color of the paper indicators. For better results, place a white bond
paper under the petri dish. Tabulate your observations. Remember these colors
because they will be your basis of comparison in identifying other materials.
5.
Keep the remaining indicator paper in tightly covered vials. This can last for several
months. Do the same to the liquid indicator. You will use these in the Activity 8-4b.
Data
Solution
Muriatic acid
Calamansi
Distilled water
Soap solution
Sodium hydroxide
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Table 8-2a
Nature of Solution
Strongly acidic
Weakly acidic
Neutral
Weakly basic
Strongly basic
Color change on Indicator Paper
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Questions
A.
Preparing indicator
Plant used:
1.
2.
B.
What was the color of the plant extract? _________________________________
What was the color of the plant extract with alum? _________________________
Making indicator paper from the indicator solution
1.
What was the color of the filter paper after a. its immersion in the indicator solution? ________________________________
b. it was dried completely? ___________________________________________
C. Finding color changes of the indicator paper
1.
What were the color changes of the indicator paper on the
Muriatic acid
Calamansi
Distilled water
Soap solution
Sodium hydroxide
2.
3.
4.
5.
6.
Which of the materials is/are strongly acidic? Weakly acidic?
Which of the materials is/are strongly basic? Weakly basic?
Which of the materials is/are neutral?
What will happen to the indicators if exposed to air for sometime?
If calamansi extract is acidic, why can it be taken by humans? In what ways is it
different
Generalization
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Student Activity Sheet 8-2
Acids and Bases
Activity 8-2b
Materials
Acid/base indicator solution
10 mL graduated cylinder
4 sets petri dish
6 droppers
test tubes
vials with cover
shampoo (different brands)
tap water
soft drinks
fruits
ammonia
test tubes
test tube holder
stirring rod
tweezers
10 mL graduated cylinder
vinegar
toothpaste
fruit juices
Alka-seltzer tablet
detergent
Procedure
A. Testing for acids and bases in common materials
1.
2.
3.
Prepare as many test tubes as there are materials to be tested.
The materials to be tested must all be in solution form. Do not add water anymore
to the liquid materials. If the material is solid, dissolve in a small test tube about ¼
teaspoon of the material with 20 mL of water. Stir the mixture well to make sure
that the solid dissolves completely in the water.
Test each liquid material by placing 1 –2 drops of it on an indicator paper. Let the
indicator to dry then paste it lightly on a paper as shown in Table 2. If you ran out
of paper indicators, prepare a new set using the remaining liquid indicator.
Data
Refer to Table 8-2b.
Questions
1.
2.
3.
4.
5.
6.
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Which of the materials is/are strongly acidic? Weakly acidic?
Which of the materials is/are strongly basic? Weakly basic?
Which of the materials is/are neutral?
Why do we study acids and bases? Explain
In what way is pH related to soil characteristics?
Research on the application of acids and bases in agriculture.
BSE-Department of Education
Generalization
Table 8-2b
A
tap
water
B
soft
drink
C
vinegar
D
fruit
juice
E
ammonia
F
shampoo
Paper indicators
G
Toothpaste
H
detergent
solution
I
Alka-Seltzer
solution
J
fruit
extract
K
vegetable
extract
L
cola
drink
Paper indicators
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Integrated Science
Week 9
Competency: Investigate physical and chemical changes taking place in the
environment.
Lesson 9-1 Physical Changes in Matter
Time Frame: one period
II.
Objectives
At the end of the activities, the students should be able to;
1. describe the changes that matter undergo during a physical change; and
2. give examples of physical changes occurring in your surroundings.
II.
Subject Matter
A.
B.
C.
Topic: Physical Changes in Matter
References: Any Integrated Science or Physical Science Textbook
Materials
piece of different materials:
paper, cloth, plastic
transparent cup
metallic spoon
blunt knife
III.
ice cubes
rubber band
modeling clay
matches
candle
Learning Tasks
A.
Motivation
1. Look around you. List down some of the things you see.
2. Are all the things in your list considered matter? Why?
3. Choose one material. (e.g. a piece of paper)
4. Describe the material. (e.g. color, shape, feel, texture)
5. Will the material appear as it is now one month after? One year after?
Give reasons for your answer.
B.
Pre-laboratory Activity
1. Prepare 6 stations for observations of the following changes:
a. changes on paper, cloth, plastic
b. changes on ice cubes
c. changes on candle wax
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d. changes on rubber band
e. changes on clay
f. changes on iron filings
BSE-Department of Education
2.
3.
4.
5.
C.
Arrange students in groups and assign each member a specific task.
Discuss objectives of the activity.
Drill on laboratory safety and procedures.
Give instructions on how students will perform the activities using the
“Stations method” (e.g. how long each group is expected to stay in one
station, should all the groups do the activities in all the stations or do at least
4). This will depend on the size of the classroom or laboratory, the number of
students, availability of materials, and level of the students. It is suggested
that the students perform at least 4 of the activities to arrive at the expected
generalization.
Activity proper
1. Ask students to perform activity on Physical Changes. Refer to the Student
Activity Sheet.
2. Move around and check if the students are doing the activity properly and on
the right track and every group member is busy. Check whether they are
following the safety procedures drilled on earlier.
3. Ask questions to check if they understand what they are doing.
D.
Discussion
1. Process data from the activity.
2. Discuss the answers to the following questions (also found in the student
activity sheet).
a. In what ways did the following materials in the activity changed?
1.
2.
3.
4.
5.
paper
cloth
plastic
ice cubes
candle wax
6.
7.
8.
9.
rubber band
clay
magnet
iron filings
b. Was there a new material formed after each change?
c. When do we say that a change is only physical?
d. Which of the materials underwent physical change? Give your reasons for
your choices.
e. What are some evidences of a physical change?
f. State an operational definition of a physical change.
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E.
Generalization
A physical change is characterized by





changes in size, shape, hardness, texture of a substance;
change in state of a substance;
no change in identity;
no formation of new substance/s;
absorption or release of energy.
F. Valuing/Application
1.
2.
3.
4.
5.
Draw the Water Cycle and label its parts.
Identify the physical changes involved in each process?
Why is the water cycle important to our lives?
What will happen if one of the processes stopped (e.g. evaporation)?
What should you do in your own small way to keep the cycle functioning
continuously?
G. Assessment
The situations below involve physical changes.
1.
2.
3.
4.
5.
sharpening of pencil
making ice candy
chopping wood
stretching a coiled spring
magnetizing a needle
6.
7.
8.
9.
10.
melting of butter
flattening milk can
making soap bubbles
peeling cassava
grinding coffee beans
Identify the specific change (e.g. size, shape, hardness, texture, state) on each
of the materials.
IV.
Agreement/Assignment
1. List some activities you do everyday that involve physical changes. Cite the
importance of these activities to you.
2. Paper Folding (Technology / Creative Arts)
a. Collect different colored papers. Make different designs (e.g. flower base or
pencil holder, fan, floor mat, book marker, etc..) through paper folding.
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Student Activity Sheet 9.1
Physical Changes in Matter
Materials
piece of different materials:
paper, cloth, plastic
transparent cup
metallic spoon
blunt knife
ice cubes
rubber band
modeling clay
matches
candle
Procedure
1. Describe a piece of paper then tear it into small pieces. Do the same for the pieces of
cloth and plastic.
How do the torn pieces look? Compare its characteristics with the original.
2. Describe some ice cubes. Leave it on the container for a few minutes. Describe what
happened to the ice cubes.
Was there a change in the ice cubes? Can the ice cubes recovered? If so, state how.
3. Scrape the side of a candle wax and collect some pieces on to a spoon. Describe the
wax pieces. Heat the spoon over a candle flame.
What happened to the candle wax. Are the characteristics of the candle wax the same
before and after heating?
4. Describe the characteristics of a rubber band. Stretch it and keep it in place for a little
while, then release it.
What happened to the rubber band? Did its characteristics change? If so, which
characteristics?
Stretch the rubber band to the fullest until it snaps.
In what ways did the rubber band change? Is this the same rubber band as before it was
stretched?
5. Cut a small piece of modeling clay. Press it with your hands.
In what ways did the clay changed?
Mold the clay into another shape.
Does the clay have the same characteristics as the original clay? Will changing the
shape change the clay into another material?
6. Describe some iron filings. Place some of the iron fillings on a piece of paper and place
a magnet near them.
What happened to the iron filings and magnet?
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Separate the iron filings from the magnet.
Was there any change on the iron filings? How about the magnet?
Data
Material observed
Initial observations
Final Observations
Questions
1.
In what ways did the following materials in the activity changed?
a.
b.
c.
d.
e.
2.
3.
4.
5.
6.
paper
cloth
plastic
ice cubes
candle wax
f.
g.
h.
i.
rubber band
clay
magnet
iron filings
Was there a new material formed after each change?
When do we say that a change is only physical?
Which of the materials underwent physical change? Give your reasons for your
choices.
What are some evidences of a physical change?
State an operational definition of a physical change.
Generalization
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Integrated Science
Week 9-Cont’d
Lesson 9-2 Chemical Changes in Matter
Time Frame: two periods
I.
Objectives
At the end of the activities, the students should be able to;
1. describe the indicators of chemical change;
2. define chemical change operationally; and
3. discuss some of the useful / beneficial and harmful effects of chemical changes to
humans and properties.
II.
Subject Matter
A.
B.
C.
III.
Topic: Chemical Changes in Matter
References: Any Physical Science or General Chemistry textbook
Materials: Refer to the Student Activity Sheet
Learning Tasks
A. Motivation
1. Ask the questions “When do we say that matter has undergone a physical
change?”
2. Give situations that illustrate matter undergoing physical change.
3. Give the difference between elements and compounds and the kinds of
elements.
4. Ask the students “What did you have for breakfast this morning? List at least
three. “ (Answers may vary: e.g. rice, fish, meat, bread, butter)
5. Describe how food was prepared. Cite some of the changes before and after
the preparation of each food.
Pre-laboratory Activity
1. Prepare 6 stations for observations of the following changes:
a. changes on bread
b. changes on egg shells and vinegar
c. changes on milk and vinegar
d. changes on sugar
e. changes on eggplant
f. changes on hydrogen peroxide and potato
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2.
3.
4.
5.
6.
Arrange students in groups.
Give each member a specific task.
Distribute student activity sheet.
Discuss objectives of the activity.
Drill on laboratory safety and procedures, e.g.,
a. heating with an alcohol lamp
b. mixing materials (e.g. solid with liquid)
c. handling chemicals
7. Give instructions on how students will go about performing the activities
using the “Stations method” (e.g. how long each group is expected to stay
in one station, should all the groups do the activities in all the stations or
go to at least 4). This will depend on the size of the classroom or
laboratory, the number of students, availability of materials, and level of
the students. It is suggested that the students perform at least 4 of the
activities to arrive at the expected generalization.
B.
Activity proper
1. Ask students to perform activity on Chemical Changes.
2. Move around and check if the students are doing the activity properly and on
the right track. and every group member is busy. Check whether they are
following the safety procedures drilled on earlier.
3. Ask questions to check if they understand what they are doing.
You may stop at this point. You can ask the students to prepare their
reports at home and be ready for the post discussion the following day.
C. Discussion
1. Ask each group to present their data to the class.
2. Process the data. Point out the similarities and differences among the data.
3. Discuss the answers to the following questions (also found in the student
activity sheet).







144
In what ways did the following materials in the activity changed?
a. bread
b. egg shells and vinegar
c. milk and vinegar
d. sugar
e. eggplant
f.
hydrogen peroxide and potato
Was there a new material formed after each change?
When do we say that a change is chemical?
Which of the materials underwent chemical change? Give your reasons for
your choices.
What are some evidences of a chemical change that can be observed?
State an operational definition of a chemical change.
Name some useful chemical changes and those that can bring beneficial
effects to humans.
BSE-Department of Education
D. Generalization
The visible and readily observable indicators of chemical changes are:




evolution of light and heat
release of a gas
formation of solid particles (called precipitate) that separate from the liquid
solution.
formation of new substances/s
E. Valuing/Application
There are many chemical changes which have useful and beneficial effects on
humans. Name some of these changes and explain why you consider them useful
or beneficial.
However, there are some chemical changes can have harmful effects to humans
and properties. Name some of these changes and explain why you consider them
harmful.
Sample answers could be:
F.





Useful
process of digestion of food
photosynthesis
fireworks in the sky
cooking of food (frying fish, boiling egg,
burning of fuel





Harmful
pollution of waterways
taking in highly acidic foods
rusting of furniture, utensils, and other materials that are made of iron
decolorizing of cloth upon long exposure to sunlight
decaying of foods
Assessment
Firecrackers are often used in celebrations to make the occasion more enjoyable.
When firecrackers explode, the occasion becomes festive.
a.
b.
What kind of change is involved in the explosion of firecrackers?
Give at least 4 evidences of that change.
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Discuss why the following changes are considered useful / beneficial.
 bleaching and dyeing of cloth
 taking in antacid
 producing methane gas from waste materials
Discuss why the following changes are considered harmful.
 dynamite fishing
 burning of gasoline in old vehicles
 decaying garbage in open garbage cans
 frequent use of bleaching powders and liquids
IV.
Agreement/Assignment
1. List down at least 10 naturally occurring chemical changes in the environment.
2. Project For You . (Technology)
“Magic with chemical change”
Dissolve 1 tablespoon of sugar in 1 tbsp. of water.
Dip the end of the matchstick on the solution. Write a word on a sheet of paper.
Dry the paper. To make the word appear, place the paper over the flame. As the
sugar in the solution used to write on the paper burns, the word will appear.
Investigate: Look for other materials that can replace sugar.
3. Link with scientists and Social Studies: Have students identify some historically
significant chemical changes, and the scientists recognized for the changes. Ask
the students to report them in class.
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Student Activity Sheet 9.2
Chemical Changes
Materials
a piece of pan de sal
or any kind of bread
small pieces of egg shells
evaporated milk
a piece of potato
vinegar
white sugar
matches
measuring cup
alcohol lamp with denatured alcohol
test tube holder
5 small clear bottles (wide-mouthed)
cutter or knife
spoon
a pc. of eggplant
3% hydrogen peroxide
rags
medicine dropper
Procedure
Station 1.
Changes on bread
Describe a piece of bread. Cut a small piece from it. With a test tube holder place it over a
flame for a minute or two or until you see changes on the bread. Describe the changes.
Does the bread look the same as the original? Do you think you can recover the original
characteristics of the bread?
Station 2.
Changes on egg shells and vinegar
Pour ¼ cup of vinegar into a clear bottle. Drop a few small pieces of eggshells into
the bottle. Observe the mixture.
What happens to both vinegar and eggshells? Is there a new substance formed? If so, what
do you think is this new substance?
Station 3.
Changes on milk and vinegar
Pour ¼ cup of vinegar into a clear bottle. Add about 20 drops of evaporated milk into the
bottle. Observe the mixture.
What happens to both vinegar and eggshells? Was there a new substance formed? If so,
what do you think is this new substance? Do you think you can still recover the original
materials?
Station 4.
Changes on sugar
Place some sugar on to a spoon. Wrap the handle of the spoon with a rug to avoid burns.
Place the spoon over a flame for about 5 minutes. Describe all the changes you observe on
sugar. Continue heating until the color becomes almost black.
Are the characteristics of sugar the same before and after heating. Is it possible to recover
the original sugar? Is the black substance formed still sugar?
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Station 5.
Changes on eggplant
Cut a small piece from the eggplant and observe its characteristics particularly the cut
section. Leave this cut section exposed to the air. Observe it again after about 5 minutes.
Does the cut section have the same color as before? What do you think will happen if the
eggplant is exposed for a longer time?
Station 6.
Changes on hydrogen peroxide and potato
Pour ¼ cup of hydrogen peroxide into a clear bottle. Add a small slice of peeled potato to
the bottle. Observe the slice of apple for a few minutes and note down any change.
What happens to the slice of apple? Is there any indication that another substance is
present? What do you think is this substance?
Data
Materials observed
Initial observations
Final Observations
Questions
1. In what ways did the following materials in the activity change?
a.
b.
c.
d.
e.
f.
2.
3.
4.
5.
6.
bread
egg shells and vinegar
milk and vinegar
sugar
eggplant
hydrogen peroxide and potato
Was there a new material formed after each change?
When do we say that a change is chemical?
Which of the materials underwent chemical change? Give your reasons for your choices.
What are some evidences of a chemical change?
State an operational definition of a chemical change.
Generalization
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Integrated Science
Week 9-Cont’d
Lesson 9-3 Effect of Heat in Matter
Time Frame: one period
I.
Objectives
At the end of the activities, the students should be able to:
1.
2.
3.
4.
investigate how energy is involved in the changes that matter undergo;
describe what happens to the volume of a solid, a liquid or a gas when it is heated;
cite situations where the heat effects on matter are useful;
recognize each one’s responsibility as a member of a community.
II. Subject Matter
A. Topic: Effect of Heat on Matter
B. References:
Rabago, Lilia M..(1997). Science and Technology I. SD Publications, Inc.
Araneta Avenue, Quezon City. pp.143-144.
Rabago, Lilia M..(1997). Science and Technology I Teacher’s Manual. SD
Publications, Inc. Araneta Avenue, Quezon City. pp. 82-84.
C. Materials: (See activity card)
III.
Learning Tasks
A.
Motivation
During town fiestas, peddlers take the opportunity to sell big, beautiful balloons.
There are times, however, when peddlers stand in corners and wait for
customers under the heat of the sun for a long time. The overheated balloons
would suddenly burst. Can you tell why this happens?
B.
Pre-laboratory Activity
a. Prepare the tray that will contain all the materials for the activity.
test tubes
glass tubing (or straw),
colored water
water
marking pen
rubber stopper
large bottle with cold water
medicine dropper
b. Arrange students in groups.
c. Give each member a specific task.
d. Discuss objectives of the activity.
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e. Drill on laboratory safety and procedures.
Inserting a glass tubing through a rubber stopper
Using a test tube
Care of glassware
C.
Activity proper
a. Ask students to perform activity as per instructions in the accompanying
Student Activity Sheet.
b. Move around and check if the students are doing the activity properly and on
the right track. See to it that every group member is busy. Check whether
they are following the safety procedures drilled on earlier.
c.
Ask questions to check if they understand what they are doing.
D. Discussion
a. Process the results that each group gathered. A group member can report
orally or place in manila paper so that other members can compare their
results.
b. Point out similarities and differences in the results.
c. Discuss the answers to the following questions (also found in the student
activity sheet).
1. What is the effect of holding the test tube tightly with your hand? Did it
have any effect on the water droplet in the glass tubing? Explain your
answer.
2. What happened to water droplet when the test tube is placed in cold
water? How do you compare this result with that in (1)?
3. What represents the volume of air in this activity?
4. What happened to the volume of air when it was heated?
5. What happened to the volume of air when it was cooled?
E.
Generalization



F.
Heating or cooling matter affects its volume.
When matter is heated, it expands. Its volume becomes bigger.
When matter is cooled, it contracts. Its volume becomes smaller.
Valuing/Application
The clinical thermometer is an instrument which depends upon the expansion
and contractions of body temperature. When heat is absorbed, the mercury
expands so it rises inside the bulb. When heat is transferred the mercury
contracts so it falls.
Using a clinical thermometer, can you tell if you have a fever? Explain your
answer.
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G.
Assessment
Refer to Fig. 9-4. in the Student Activity Sheet for the following questions:
1. If heated, which of the following would most likely happen to the water level in
the glass tubing? The water level will
a. remain the same.
b. rise up the tube.
c. move down the tube.
2. Which of the following would best explain your observation?
a. Matter is not affected by heat.
b. Matter expands when cooled.
c. Matter contracts when cooled.
3. If the water inside the test tube is placed in cold water, which of the following
would most likely happen to the water level in the glass tubing?
a. remain the same.
b. rise up the tube.
c. move down the tube.
4. Which of the following would best explain the result?
a. Matter is not affected by heat.
b. Matter expands when cooled.
c. Matter contracts when cooled.
IV.
Agreement/Assignment
Making An improvised thermometer
1.
With a soft drink bottle, a straw, a rubber stopper, and colored water, construct
an improvised thermometer.
2. Using your improvised thermometer, observe hotness and coldness of the
surroundings during the day. Do this for one week
a. Which part of the day usually indicates the highest temperature?
b. Which part of the day usually indicates the lowest temperature?
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151
Student Activity Sheet 9.3
Effect of Heat on Volume of Air
Materials
test tubes
glass tubing (or straw),
colored water
water
marking pen
medicine vials,
rubber stopper
large bottle with cold water
medicine dropper
Procedure
1. Prepare the setup as in Fig. 9-3.
2. Put a drop of colored water in the glass tubing. Do this carefully to keep the drop of
water in the tubing. Mark the position of the drop of water. Hold the test tube tightly in
the palm of your hand for about 5 minutes. Heat from your hands will flow to the test
tube and the air inside the tubing. Observe any changes in the level of the water droplet.
What happens to the drop of water as the air in the test tube is heated? What do you
think has caused this to happen?
3. Place the test tube in a large bottle with cold water.
Was there a change in the level of the water droplet? If so, what caused this change?
Questions
Drop of water
1. What is the effect of holding the test tube
tightly with your hand? Did it have any effect
on the water droplet in the glass tubing?
Explain your answer.
2. What happened to water droplet when the
test tube is placed in cold water? How do
you compare this result with that in (1)?
3. What represents the volume of air in this
activity?
4. What happened to the volume of air when it
was heated?
5. What happened to the volume of air when it
was cooled?
Glass tubing
Rubber
stopper
Test tube
Air
Fig. 9-4
Generalization
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BSE-Department of Education
Integrated Science
Week 9-Cont’d
Lesson 9-4 Energy Involved in a Chemical Change
Time Frame: two periods
I.
Objectives
At the end of the activities, the students should be able to:
1. compare the heat conducting properties of water and paper by boiling water; and
2. estimate the heat produced by a burning candle.
II.
Subject Matter
A. Topic: Heat Energy of a Chemical reaction
B. References: Any Integrated Science or Physical Science Textbook
D. Materials:
pieces of bond paper
2 iron rings and clamps
2 candles
2 iron stands
matches
2 test tube holders or tongs
water
III.
Learning Tasks
A. Motivation
1. Recall the meaning of heat. Ask the questions: “Can we see heat? Can we feel
it? Can we measure it? How do scientists measure heat? What is the unit of
heat?” What is the effect of heat on objects? On people? Give examples.
2. Demonstrate to the class the effect of heat on dry paper and a paper wet with
water. Prepare 2 setups each composed of an iron ring attached to an iron
stand. You can also use a tripod in place of an iron ring, if available. Draw a 4column table on the board.
Improvise 2 paper cups. Place each over the iron ring. Place a candle under
each cup. Before you light the candles, ask the students to make predictions as
to what will happen when each candle is lighted. Record their predictions in
column 1 on the board.
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Light the candle under the first cup. Ask the students to describe their
observations. You need not let the flame consume all the paper if it will pose
any danger. You can put off the flame when you think enough observations
have been given. Write the observations in Column 2. Light the candle under
the cup with water. Let it burn for a few minutes until you think the students
have noted the differences. Let them write their observations in the third
column. In Column 4, let them give their explanations on their observations
particularly on why the second cup did not burn.
Analyze the results. The conclusion of the students should be that “the second
cup does not burn because the water removes heat from the paper before the
paper becomes hot enough to burn.”
3. Tell the students that in the next activity, they will calculate the amount of heat
produced by the candle. Ask the students what they know about calories. They
probably have read this on food labels. They have heard this from people who
are dieting or controlling their food intake. Emphasize that a candle burns its
wax with oxygen from the air releasing calories of energy (heat and light). In a
similar way, our body burns food, though without a flame, to release energy
(heat).
B.
Preliminary Activity
1.
2.
3.
4.
5.
Prepare the materials for the demonstration and students’ experiment before
the class starts.
Write on the board a large 4-column table for the students’ data.
After the demonstration, distribute the trays containing the materials for the
experiment to each group.
Distribute the Student Activity Sheet and discuss the objectives of the
activities.
Drill on laboratory safety and procedures, e.g.,
a.
b.
c.
d.
C.
heating with a candle and test tube
use of the test tube holder
handling chemicals
measuring with calibrated glassware (graduated cylinder, thermometer)
Activity proper
1. Ask students to perform Activity 9-4 Heat Energy of a Chemical Change.
2. Move around and check if the students are doing the activity properly and on
the right track and every group member is busy. Check whether they are
following the safety procedures drilled on earlier.
3. Ask questions to check if they understand what they are doing.
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E.
Discussion
1. Calories and Joules are units of heat.
2. Calorimetry is the measurement of heat flow.
3. When heat is transferred to an object, the temperature of the object
increases. When heat is removed from an object, the temperature of the
object decreases. The relationship between the heat ( Q ) that is transferred
and the change in temperature ( DT ) is
Q = mC T = C ( Tf - Ti )
The proportionality constant in this equation is called the heat capacity ( C ).
The heat capacity is the amount of heat required to raise the temperature of
an object or substance one degree. The temperature change is the difference
between the final temperature ( Tf ) and the initial temperature ( Ti ).
Quantity
Symbol
Unit
heat
Q
joule (J)
Energy transfer that produces or results from a
difference in temperature
temperature
T
o
Measure of the kinetic energy of molecular motion
temperature
change
DT
o
Difference between the final and initial
temperatures for a process
heat capacity
C
C or K
C or K
Cal/oC or
J/oC
Meaning
Heat required to change the temperature of a
substance one degree
A calorimeter is an experimental device in which a chemical reaction or
physical process takes place. The calorimeter is well-insulated so that,
ideally, no heat enters or leaves the calorimeter from the surroundings. For
this reason, any heat liberated by the reaction or process being studied must
be picked up by the calorimeter and other substances in the calorimeter.
E.
Generalization



The heat given off by the burning candle is equal to the heat absorbed by
water.
An increase in temperature of water indicates the absorption of heat.
The production of new substances from the burning candle, the decrease in
its mass (in an open system), change in temperature, production of heat and
light, all indicate that a chemical change has taken place. The new
substances are black soot (carbon), gases (carbon dioxide, carbon
monoxide, and water vapor).
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F.
Valuing/Application
1. Different substances have different heat capacities because of the kinds of
molecules and atoms they posses. This means that for the same mass,
different substances need different amounts of heat to change their
temperatures 10C.
2. Foods rich in carbohydrates are called energy-giving foods because they give
off large amounts of heat when they are burned.
3. Water’s heat capacity plays a major role in keeping us warm. The large heat
capacity allows water to hold heat for a long time. Waters heat capacity
controls the weather surrounding large bodies, such as the ocean. With water
gaining all the heat though the day it slowly releases it during the night. This
regulates the temperture of the area. With waters large heat capacity it allows
us to hold heat better than most subtances. All organisisams have a
temperture range. Humans have a range through 32 degrees to 43 degrees
celcius. Humans are 87% water, because they do not have a large
temperture range.
G.
Assessment
1. Which of the following changes indicate the removal or release of heat?
a. when rain becomes clouds
b. when clouds become rain
c. when rain stays in liquid form
d. when water from the sea
changes into clouds
2. When you apply a few drops of alcohol on your hands, the spot feels cool
while the alcohol is evaporating. Which statement below accounts for this
observation?
a.
b.
c.
d.
IV.
the heat from the skin was absorbed by alcohol.
the alcohol has lower temperature so it feels cool on the skin.
the heat from the skin was used to separate the alcohol molecules.
The amount of heat possessed by the body is lower than the amount of
heat possessed by alcohol.
Agreement/Assignment
1. Plan an experiment to show the effect of color of a material on the amount of heat
absorbed by the material.
2. Conduct an investigatory project to determine which alternative source of heat like
dry bagasse, rice hulls, wood chips, or peanut sheels release the greatest amount
of heat. You may vary the kind of material and keep all other variables constant..
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Student Activity Sheet 9.4
Heat Energy of a Chemical Change
Materials
candle
water
test tubes
test tube holder
small beakers
beam balance
small plastic saucer
10 mL graduated cylinder
thermometer
Procedure
1. Get the combined mass of the candle and plastic saucer with a beam balance. Assign
this as initial mass, m1.
2. Pour 10 mL water into a test tube. Take the temperature of the water. Assign this as
initial temperature, ti.
3. Let the candle stand firmly on the saucer. Carefully light the candle, then hold the test
tube with a test tube holder in the flame. Move the test tube gently in small circles while
in the flame for even distribution of heat.
4. Continue heating for about three minutes. Take the temperature of water just before
removing the test tube from the flame. Assign this as final temperature, tf.
5. Put off the candle. Get again the combined mass of the candle and the saucer. Assign
this as final mass, m2. Calculate the mass of the candle after burning.
6. The heat produced by the burning candle is determined through the amount of heat
absorbed by the water . Thus, the heat absorbed by water from the burning candle is
equal to the product of the heat capacity of water (1 cal/oC) , the mass of water (Dwater
= 1g/mL), and the change in temperature of water.
Data
Material observed
Initial observations
Final Observations
Water
Initial temperature =
Volume =
Mass of water =
(D=m/v)
Final temperature =
Volume =
Mass of water
(D=m/v)
Candle
Mass of candle
and saucer =
Mass of candle
and saucer =
Mass of candle =burned
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Questions
1. Which has a higher temperature, water before heating or water after heating? To what is
the change in temperature due?
2. Did water produce heat or absorb heat?
3. Did candle produce heat or absorb heat? Why is the mass of the two materials be
equal?
6. Why was the mass of water used in the calculation and not the mass of the candle?
7. What happened to the mass of the candle after it was burned? What does this indicate,
a physical change or a chemical change?
8. Name the chemical changes that took place in the activity.
9. How much heat is evolved in burning 1g of candle?
Generalization
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Integrated Science
Week 10
Competency: Describe the properties of matter in terms of its component atoms
or molecules
Lesson 10-1 Molecules of Matter
Time Frame: one period
I.
Objectives:
At the end of the activities, the students should be able to:
1.
2.
3.
4.
5.
II.
give examples of molecules;
cite evidences that molecules of matter are in constant motion;
infer that there are spaces between molecules;
compare diffusion of molecules in different materials; and
explain diffusion in terms of the molecular model of matter.
Subject Matter:
A. Topic: Molecular Theory of Matter ; Diffusion of Molecules
B. References:
Gutierrez, Marlene M. (1999). Science and Technology for the Modern World.
Diwa Scholastic Press Inc. Makati City. pp. 116 - 119
Gutierrez, Marlene M. (1999). Science and Technology for the Modern World .
Teacher’s Manual. Diwa Scholastic Press Inc. Makati City. pp. 106 - 109
Rabago, Lilia M. (1997). Science and Technology I. SD Publications. Araneta
Avenue, Q.C. pp 84 - 86
Rabago, Lilia M. (1997). Science and Technology I Teacher’s Manual. SD
Publications. Araneta Avenue, Q.C. pp. 47 - 49
C. Materials:
For the students: Refer to the Student Activity Sheet
For the teacher: Visual Aids; Manila Paper
III. Learning Tasks
A.
Motivation:
Have you experienced smelling the food your neighbors are cooking? Surely you
could tell the difference between the smell of adobo and fried tuyo or tinapa.
Similarly, if you put some kalamansi juice into a glass of water, the whole glass of
water will taste sour almost immediately.
What will happen to the taste of water if you add a pinch of salt or sugar?
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B.
Preliminary Activity
1.
2.
3.
4.
5.
C.
Preparation of materials per group:
Arrange students in groups.
Give each member a specific task.
Discuss objectives of the activity.
Drill on laboratory safety and procedures.
Proper use of chemicals
Correct mixing and smelling techniques
Activity Proper
1. Ask students to perform activity on Diffusion of Molecules. Refer to the
Student Activity Sheet.
2. Move around and check if the students are doing the activity properly and on
the right track and every group member is busy. Check whether they are
following the safety procedures drilled on earlier.
3. Ask questions to check if they understand what they are doing.
D.
Discussion
1. Compare the data gathered by the different groups. Look for similarities and
differences.
2. Ask the students to explain why there are differences in the data.
3. Discuss the answers to the Guide Questions. Refer to the Student Activity
Sheet.
4. Discuss the Molecular theory. Use this theory to explain the diffusion of
molecules.




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Molecular theory states that:
a. Matter is made up of very tiny particles called molecules.
b. Attractive forces exist between molecules.
c. Molecules are continually moving.
d. There are spaces between molecules.
Attractive forces exist between molecules. The forces of attraction are
greatest in solids because molecules are very near each other. They are
weakest in gases because the molecules of gases are far from one
another.
Molecules of gases can move freely, as far as the space will allow them.
Thus the volumes of gases depend on their containers.
Molecules of gases are continually moving in all directions. They bump
with each other, with the walls of the container, and with other molecules
that cross their path.
BSE-Department of Education
Diffusion happens because molecules of a substance are in constant
motion. When placed in a medium, they continue to move, and as they
move they bump each other. They also bump the molecules of the
medium and are in turn bumped by other molecules. The spaces between
molecules of the medium allow the molecules of the substance to spread
throughout the medium.
Table 10-1. Comparison between solids, liquids, and gases
Basis of
Comparison
a. Intermolecular
space
b. Molecular
attractions
c. Molecular
motion
D.
Solid
Smallest distance
between molecules
Liquid
Gas
back and forth
Small space
between
molecules
slip and slide
Large space
between
molecules
moves freely
slowest
slow
fastest
Generalization





Molecule is the smallest stable unit of matter and possesses all the properties
that identifies that matter.
Attractive forces exist between molecules.
Spaces exist between molecules.
Molecules of a substance spread throughout a medium. They spread fastest in
gaseous medium and slowest in solid medium.
Molecules of solids, liquids, and gases differ in terms of intermolecular space,
molecular attraction, and molecular motion.
E. Valuing/Application
1. Why do bottles of alcohol, acetone, soft drinks, wines, and other similar
materials have the following labels:” Keep tightly closed when not in use.”
2. What should you do to your garbage can so that bad smell and probably
airborne bacteria will not reach you?
3. Explain why some food additives like food colors are added to soft drinks, and
juices.
4. Many Batik cloths are made through “Tie Dyeing”.
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F.
Evaluation:
Answer the following questions:
a. Why can you smell the odor of the food your mother is cooking in the
kitchen?
b. Why does water flow?
c. Draw the arrangement of molecules in solids, liquids and gases.
IV.
Agreement/Assignment
Answer briefly:
1.
2.
3.
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Why should you cover your nose when someone in the room is smoking?
Why should you cover your mouth whenever you cough?
Many people from far away provinces opposed the operation of the Bataan
Nuclear Power Plant because an accident in this plant would affect them. Do
you think it is true? Why or why not?
BSE-Department of Education
Student Activity Sheet 10.1
Diffusion of Molecules
Materials
1 slice of cooked gulaman or gelatin
¼ tsp of blue dye
watch with second hand
teaspoon
medicine dropper
bottle of bagoong
soy sauce
clear bottles
water
Procedure
A.
B.
C.
Place a slice of cooked gulaman or gelatin on a plate. Sprinkle ¼ tsp of blue dye on the
surface of the gelatin. Record the time when you did this. Set the gelatin aside and
observe how long it will take the blue dye to penetrate the Describe the movement of
the dye.
Place a drop of soy sauce into a half bottle of water. Record the time you dropped the
soy sauce into the water. Observe the water for a few minutes without moving the
glass. Note down your observations.
Place a small bottle of bagoong in a box. Cover the box. Ask a group mate to sit about
2 ft. away from you. Tell her to record the time the moment she smells the bagoong.
Record the initial time then open the box.
Data
Name of materials
Observations on the materials before and after diffusion
a. Gulaman
Blue dye
b. Soy sauce
Water
c. Bagoong
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Guide Questions
A. 1.
2.
3.
4.
5.
B. 1.
2.
3.
4.
What happened to the blue dye? Did you observe any change? Describe the
change.
Did you see any change in color of gulaman? If so, what caused this change?
Did your observations show that the blue dye spread in the gelatin?
How long did it take the potassium permanganate crystals to spread down this far?
Infer a reason for the spread of the dye in gelatin.
What happened to the soy sauce as it was dropped into the glass of water?
What happened to the soy sauce and water after a few minutes?
How long did it take the soy sauce to spread completely?
Infer a reason for the spread of the dye in gelatin.
C. 1.
2.
3.
4.
5.
6.
What happened when the bottle of bagoong was was uncovered?
How long did it take for the odor to reach you?
What was the smell of bagoong in the bottle?
How did the smell of bagoong reach your classmate?
How did the odor reach you?
How long did it take for the odor to reach you? Why did it still reach you when you
are farther away from the source?
7. Give examples of diffusion particles in liquid and in gas.
Generalization
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Integrated Science
Week 10-Cont’d
Lesson 10-2 Intermolecular Attraction
Time Frame: one period
I.
Objectives
At the end of the activities, the students should be able to:
1.
2.
3.
4.
illustrate by examples capillarity and surface tension;
show how the molecular theory explains surface tension and capillarity;
differentiate adhesion from cohesion; and
appreciate the value of sensitivity in solving problems.
II. Subject Matter
A. Topic: Surface Tension, Capillarity (Adhesion. Cohesion)
B. References:
Gutierrez, Marlene M. (1999). Science and Technology for the Modern World.
Diwa Scholastic Press Inc. Makati City. pp. 120 - 122
Gutierrez, Marlene M. (1999). Science and Technology for the Modern World .
Teacher’s Manual. Diwa Scholastic Press Inc. Makati City. pp. 111 - 112
Rabago, Lilia M. (1997). Science and Technology I. SD Publications.
Araneta Avenue, Q.C. pp 86 – 88
Rabago, Lilia M. (1997). Science and Technology I Teacher’s Manual. SD
Publications. Araneta Avenue, Q.C. pp. 48 - 49
C. Materials:
For the students: Refer to the Student Activity Sheet
For the teacher: Illustration: Attraction between molecules;
Picture of any insect striding on the surface of the water
Spring of a ball pen, basin, water
III.
Learning Tasks
A.
Motivation
Gently lay on top of the basin of the water a spring from a ball pen. (If done
properly spring floats.) Can you give some explanations why the spring floats on
water?
Remove the spring from water. Wipe it dry. Touch one end of the spring to the
surface of the water, then pull it up. What happens? What is the force that allows
the water to be pulled up against gravity?
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B.
Preliminary Activity
1.
2.
3.
4.
Prepare the materials per group.
Arrange students in groups and give each member a specific task.
Discuss objectives of the activity.
Drill on laboratory safety and procedures.
C. Activity Proper
1. Ask students to perform activity on Surface Tension and Capillarity. Refer to
the Student Activity Sheet.
2. Move around and check if the students are doing the activity properly and on
the right track and every group member is busy. Check whether they are
following the safety procedures drilled on earlier.
3. Ask questions to check if they understand what they are doing.
D. Discussion
1. Compare the data gathered by the different groups. Look for similarities and
differences.
2. Ask the students to explain why there are differences in the data.
3. Discuss the answers to the Guide Questions. Refer to the Student Activity
Sheet.
4. Recall the models used to represent the arrangement of molecules in solids,
liquids, and gases. Ask the questions: Why is iron hard to break? Why can
water flow while iron cannot?
5. Review the Molecular theory. Ask the question: why can we not keep a gas in
our hand while we can do so with solids? Or we can do it on a limited scale with
liquids? Use this theory to explain the observations on the needle and water,
and the varying levels of water in the plastic straws.
Molecular Theory of Matter:
a.
b.
c.
d.
Matter is made up of very tiny particles called molecules.
Attractive forces exist between molecules.
Molecules are continually moving.
There are spaces between molecules.
6. Relate capillarity with adhesion and cohesion.
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E. Generalization





Intermolecular forces of attraction exist between molecules of solids, liquids,
and gases. The difference in the strength of these attractions accounts for the
difference in arrangement of the molecules. The attraction is strongest in
solids and weakest in gases.
The strong attraction of water molecules to one another on the surface of the
water drop results in a seemingly thin, elastic film or membrane covering the
liquid. This effect is called surface tension. It is strong enough to support
objects that are more dense than water such as the needle or water striders
The rise of a liquid in a tube of small diameter is called capillary action or
capillarity. It is also a manifestation of the presence of strong attractive forces.
A liquid rises in a straw because of the stronger attraction between the
molecules of straw and water.
Adhesion is the attraction between two different kinds of molecules. (attraction
between the molecules of the straw and those of water).
Cohesion is the attraction between the same kind of molecules (attraction
between the molecules of water).
F. Valuing/Application
There should be solidarity or cohesion among the members of a family, especially
in times of troubles or difficulties. Everyone should be sensitive to each other’s
needs and problems. Togetherness or oneness help lighten the difficulties and
finding solutions becomes much easier. Everyone in the family, from oldest to
youngest, is expected to adhere to the principles inculcated by the parents in
facing/solving life’s trials.
If water striders and other insects can walk on the surface of water, can
humans do the same?
In the critically-acclaimed movie “Crouching Tiger Hidden Dragon,” there was a
scene when actors run on the surface of water. Is it possible?
Why do liquids rise in the straw as you drink your soda or softdrink?
G. Evaluation
Choose the letter of the best answer:
1. The rise of water from the roots to all parts of the plants is
called
a.
b.
capillarity.
cohesion and adhesion.
c. gravitational force.
d. surface tension.
2. Iron filings do not sink when placed slowly on the surface of the water because
of
a.
adhesion.
b.
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capillarity.
c. cohesion.
d. surface tension.
167
3. Intermolecular attraction is greatest in:
a.
gases.
b.
liquids
c. plasma
d. solids.
4. Which of the following is part of the molecular theory of matter?
a.
b.
c.
d.
molecules of matter are static.
molecules of gases are very close each other.
strong attractive forces exist between molecules of a solid.
energy of molecules can be converted ot other forms.
Identify the following:
5. Attraction between the same kind of molecules. (cohesion)
6. Rising of liquid inside fine tubes. (capillarity)
IV. Agreement
1. Give other examples of natural phenomena involving reactions of matter.
2. Research on the processes followed in waste recycling and cite waste recycling
practices carried out in the country.
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Student Activity Sheet 10.2
Activity 10-2a Surface Tension
Materials
glass of water
clean bowl
clean cloth or tissue paper
a needle
detergent solution
medicine dropper
Procedure
1. Carefully pour water into a clean bowl.
2. Gently place a dry needle horizontally on the surface of the water. Observe what
happens to the needle.
3. Remove the needle from the water and wipe dry with a clean cloth.
4. Gently place the needle, vertically this time, into the water. Compare your observation
here with the one you made in step 2.
5. Remove the needle again and wipe dry.
6. Repeat steps a and b. This time add 2 – 3 drops of detergent solution along one side of
the bowl. Observe what happens to the needle.
Data
Materials
Observations
Questions
1. In procedure 2, did the needle float or sink in water? Explain your answer in terms of
the molecular theory.
2. In procedure 4, did the needle float or sink in water? Explain your answer in terms of
the molecular theory.
3. In procedure 6, what happens to the needle after adding some detergent to water? What
was the effect of the detergent solution?
4. Have you watched insects called water striders play on the surface of a pond? What
have you observed?
Generalization
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Activity 10-2b: Capillarity
Materials
3 colorless plastic straws
(different diameter with the same length)
a glass of colored water
Procedure
1. Label the plastic straws A, B, and C. Dip the straws at the same time into a glass of
colored water. Note down the amount of water that enters in each straw.
Data
Materials
Observations
Questions
1.
2.
3.
4.
5.
In which straw did the water rise the highest? the lowest?
Why are the levels of water different in the three straws?
Why does the colored water rise in the straw?
Do straw and water have the same kind of molecules?
In what other situations do you observe a liquid rising in a small tube?
Generalization
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Integrated Science
Week 10-Cont’d
Lesson 10-3 Symbols of Atoms and Molecules
Time Frame: one period
I.
Objectives
At the end of the activities, the students should be able to:
1.
2.
3.
4.
describe how chemical elements are arranged in the periodic table;
write the symbols of some elements and state how they were derived;
name the element, given its symbol;
determine the elements, the number of atoms of each element that comprise a
formula unit of a compound;
5. differentiate an atom and a molecule; and
6. state the importance of elements and compounds in our lives.
II. Subject Matter
A. Topic: Symbols of Atoms and Molecules
B. References: Any Integrated Science or Physical Science Textbook
C. Materials: refer to the Student Activity Sheet 10-3
III.
Learning Tasks
A. Motivation
1. Recall some of the symbols used to represent safety measures that must be
observed in and out of the laboratory.
2. Modern scientists use letters to represent symbols of elements and formulas of
compounds. Show the Periodic Table. Ask the following questions: what do you
see in the Periodic Table? (letters in each box, some boxes have only one
capital letter , others have 2 letters with only the first letter capitalized.
Elements arranged in rows and columns).
3. Call one representative from each group and ask them to come to the front.
Ask them to group themselves in at least 2 ways. (Students may group
according to height, weight, age, color, sex, group number, surname, etc…)
B. Lesson Proper
1. Show again the Periodic Table. Tell the students that just like people, elements
are grouped according to some criteria. What criteria were obviously used in
the Periodic Table? (increasing number from left to right and top to bottom,
decreasing size from left to right and increasing size from top to bottom if
provided in the Periodic Table).
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2. Based on the periodic Table, state that
 More than 100 elements have been discovered or artificially-made;
 Elements are represented by symbols (letter/s);
 They also represent atoms of the elements;
 Atoms of elements have different masses and increases from left to right
and from top to bottom;
 Atoms of elements have atomic numbers, representing the number of
protons and electrons, also increases from left to right and from top to
bottom;
 No two different elements have the same symbols.
3. Symbols of elements are used for the names of elements. The present system
was devised by Johann Jacob Berzelius. He used the first letter , or combining
the first letter and another letter of the English, Latin, or Greek name of the
element. Only the first letter is capitalized. Some names were derived from the
places they came from.
Here are some symbols of elements and their derivation:
Element
Symbol Derivation
Hydrogen
H
Helium
He
Carbon
C
Calcium
Ca
Chlorine
Cl
Cobalt
Co
Nitrogen
N
Nickel
Ni
Neon
Ne
Sulfur
S
Silicon
Si
Iodine
I
Copper
Cu
Cuprum
Iron
Fe
Ferrum
Lead
Pb
Plumbum
Mercury
Hg
Hydrargyrum
Potassium
K
Kalium
Silver
Ag
Argentum
Sodium
Na
Natrium
Tin
Sn
Stannum
Gold
Au
Aurum
3. Elements may be classified into metals, nonmetals, and metalloids.
Compound may be classified as acids, bases, and salts.
4. Give the difference between an atom and a molecule; monatomic and diatomic
molecules.
5. Majority of gases are unstable. They often exist in nature as diatomic
molecules. Ex. O2, N2, Cl2, I2. See the illustrations Fig. 7.1 and &.2 p.103
Rabago, Lilia M., et, al (1997). Science and Technology, General Science.
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6. Compounds are represented by 2 or more different symbols, also called
formulas. Ex. CO, CO2, H2O, NH3, HNO3, H2SO4. Describe what the letters and
numbers represent. Explain how the Law of Definite Composition is applied in
writing chemical formulas.
Here are formulas of some chemical compounds:
Compound
Sucrose (sugar)
Acetic acid (vinegar)
Sodium chloride
Calcium oxide (lime)
Calcium hydroxide (limewater)
Calcium carbonate (limestone)
Hydrochloric acid (muriatic acid)
Hydrogen peroxide (agua oxigenada)
Methanol (denatured alcohol)
Sodium bicarbonate (baking soda)
Silicon dioxide (quartz/sand)
Chemical Formula
C12H22O11
CH3COOH
NaCl
CaO
Ca(OH)2
CaCO3
HCl
H2O2
CH3OH
NaHCO3
SiO2
Give the names and number of the atoms of elements comprising each formula
unit.
C. Discussion
An atom is the smallest particle of an element. Two or more atoms can bond
together to form a molecule. A compound is formed from the combination of at
least two different atoms, which has properties quite different from the atoms in it.
For example, sodium (Na), an extremely reactive, nearly explosive metal, and
chlorine (Cl), a toxic yellow gas combine to form sodium chloride (NaCl), which is
common table salt, a white crystalline solid.
Atoms are made up of even smaller things called subatomic particles. There are
three main types: proton (which has a very small positive electrical charge),
neutron (which is neutral), and electron (which has a very small, negative electrical
charge). You may see these referred to as p+, e–, and no. The protons and
neutrons form the nucleus of the atom (not to be confused with the nucleus of a
cell), while the electrons are constantly moving outside the nucleus and traveling at
about the speed of light.
The number of protons and electrons is important: this determines the nature of the
element. Each element has a different number of protons, and if the number of
protons in an atom is different changes, then you get a different element. The
number of protons in an atom is called its atomic number. Normally, the number
of protons and electrons match so the charge is balanced out.
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Within limits, the number of neutrons and electrons in an atom can vary. Isotopes
are atoms of the same element with different numbers of neutrons. Protons and
neutrons have about the same mass, but electrons are so much smaller, their
mass is negligible by comparison (like carrying a feather when you weigh yourself
on the bathroom scale).
The atomic mass of an element is the mass of an atom of that element compared
to the mass of an atom of carbon-12 expressed in atomic mass unit (amu).
A molecule is a combination of 2 or more atoms linked together by a network of
chemical bonds.
Elements are represented by symbols, compounds by formulas.
The symbol can stand for a) the name of the element b) one atom of the element
c) a quantity of the element equivalent to its atomic mass.
A chemical formula stands for the name of the compound, or a formula unit of the
compound. It follows the Law of Definite Composition. The subscripts give the
number of atoms of each element in a formula unit.
The Law of Definite Composition states that elements combine in a fixed mass
ratio to form a compound.
F. Valuing/Application
Discuss where the compounds are found and their common uses.
Characteristics and uses of some elements and their compounds
Lead – Its Latin name Plumbum was made the basis for plumbing, a term
associated with water pipes and lead was once its major component. Many of lead
compounds are poisonous. They are used in paint pigments and explosives.
Mercury – It is the only metal that is liquid at room temperature. It is a a dense
substance whose properties are used for making thermometer (from the Greek for
measure heat) and barometers (from the Greek for measure weight). It is a
poisonous substance associated with an incident in the village of Minamata in
Japan. During the 1960’s, industrial discharges of mercury into the sea ended up in
the fish that the local population ate. The result was Minamata disease, which
caused people to lose control of their nervous system.
Iodine – It is poisonous in its pure form but its compounds are essential to life.
Iodine dissolves in alcohol to give tincture of iodine, used as disinfectant.
Tin – At ordinary temperatures, tin is a white lustrous metal. At temperatures below
13oC, the metal slowly changes to gray, which is brittle. This causes tin roofs to
decay at very low temperatures. Tin is used to coat other metals to stop them from
corroding. “Tin” can are made from tinned iron.
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Calcium – Its compounds are very common in the Earth’s crust. It is found in
minerals like chalk, limestone and marble (CaCO3, calcium carbonate), gypsum
(CaSO4, calcium sulfate) found in blackboard chalks, and fluorspar (CaF2, calcium
fluoride) used in toothpastes, lime (CaO, calcium oxide) neutralizing acidic soil.
Potassium – It is found in the mineral feldspar (KALSi3O8, potassium aluminum
silicate). Its compounds like potassium nitrate is used in fertilizer, explosives, and
photography.
Chlorine – It is a poisonous gas with an irritating odor. It’s compound, sodium
chloride is used in foods. Its other compounds like sodium hypochlorite and
hydrochloric acid is used as cleaners, bleach, and pesticides in DDT.
Sulfur – It is normally associated with volcanoes. The bad eggs smell near
volcanoes come from compounds of sulfur like hydrogen sulfide (H2S) and sulfur
dioxide (SO2). Sulfuric acid (H2SO4) is one of the gases responsible for acid rain.
Silicon – One of its compounds is silica (SiO2) which is the pure form of sand.
Silica is also used in making glass and in computer chips.
Aluminum – It is a common component of most rocks. Sapphire and ruby are forms
of aluminum oxide (Al2O3).
G. Assessment
1. Give the name of the element represented by each symbol
a. Na
f. Ne
b. K
g. Ca
c. Pb
h. Cl
d. Ag
e. Cu
e. Sn
f. Si
2. Give the name of each element and the corresponding number of atoms in a
formula unit of the following compounds:
a. limestone, CaCO3
b. sulfuric acid, H2SO4
c. baking soda, NaHCO3
d. vinegar, CH3COOH
e. limewater, Ca(OH)2
f. nitric acid, HNO3
3. Give at least 3 elements, one compound for each and their uses.
IV.
Agreement/Assignment
1. What is a chemical reaction? a chemical equation?
2. What are the rules in writing a chemical equation?
3. Name some chemical reactions taking place around you and try to represent them
with chemical equations
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Integrated Science
Week 10-Cont’d
Lesson 10-4 Chemical Reactions in the Environment
Time Frame: two periods
I.
Objectives
At the end of the activities, the students should be able to:
1.
2.
3.
4.
5.
6.
describe a chemical equation;
analyze some chemical reactions based on given rules;
write the chemical reactions involved acid rain production;
determine the effect of acid rain on limestone rock;
identify the substances used in the reactions and the products formed; and
explain the effect of acid on limestone statues and buildings.
II. Subject Matter
A. Topic: Chemical Reactions in the Environment
B. References:
Rabago, Lilia M., et, al (1997). Science and Technology, General Science.SD
Publications Inc., Araneta Ave., Q.C.
Villamil, Aurora M. (1998). Science and Technology I. Integrated Science
Teacher’s Manual. Abiva Publishing House, Inc. Quezon City. pp. 29-30
C. Materials: refer to the Student Activity Sheet 10-3
III.
Learning Tasks
A. Motivation
1. Recall some of the chemical changes taken up in Activities 72- and 9-2.
(a. heating of iron and sulfur, b. heating of copper sulfate, c. heating of sugar,
d. eggshells and vinegar).
Why were they considered chemical changes and not just physical changes?
(production of new substances). These changes involved chemical reactions
where substances, elements and/or compounds, reacted to produce new
compounds. Recall the products of the four reactions. (a. iron sulfide, b.
anhydrous copper sulfate and water, c. carbon and water, d. calcium
acetate, carbon dioxide and water).
The reactions can be illustrated with chemical equations. What do chemical
equations consist of? How are they written?
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2. Recall some of the mathematical equations that you have used so far.
D = M/V ; A = L x W ; V = L x W x H ; P = F/A ;
A =  r2
What are the parts of the equations? What does each part signify?
3. In Science, particularly in Chemistry, we also write chemical equations. Show
the simple chemical equations below:
a.
b.
c.
d.
e.
Fe + S  FeS
CaO + H2O  Ca(OH)2
Mg + HCl  MgCl2 + H2
H2CO3  H2O + CO2
HCl + NaOH  HOH + NaCl
Describe the parts of each equation. (reactants, products, plus (+) sign, arrow
to represent equal, and numbers before the formulas). You may either give the
names of the formulas or you can ask the students to do so if they are already
with them. You can tell that the equations are representatives of the 4 general
types of chemical equations. Tell the students that they will learn detailed
formula writing in Chemistry in the third year. At this point it is enough that they
become familiar with the formulas of some compounds that they will encounter
in later topics like Lithosphere, Hydrosphere, etc.
4. Tell the students that in today’s lesson they will study only the simple reactions.
They will apply this knowledge in an experiment that simulates acid rain. They
will find out what happens to rainwater, one of the reactants, in the presence of
gases like sulfur dioxide and nitrogen dioxide and write the appropriate
chemical reactions.
B. Preliminary Activity
1.
2.
3.
4.
Prepare the materials and put in respective trays.
Arrange students in groups and give each member a specific task.
Discuss objectives of the activity.
Drill on laboratory safety and procedures.
Observing reacting materials
Mixing materials
Use of glassware
C. Lesson Proper
1. Discuss
a. what chemical equations show;
b. some principles to remember in writing chemical equation;
c. the rules in writing equation.
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2. Analyze the equations below and see whether it conforms to the principles and
rues in writing chemical equations.
a.
b.
c.
Combination Reaction
Fe
+
S  FeS
one atom of iron reacts with one atom of sulfur to form a compound
of iron sulfide consisting consisting of one atom of iron and one atom of
sulfur.
Combination Reaction
CaO
+
H2O
One molecule of
one molecule of
calcium oxide reacts
water
Single Replacement
Mg
+
HCl 
magnesium
hydrogen
atom
chloride
compound
MgCl2
magnesium
chloride
compound
Decomposition
d. H2CO3

H2O
+
hydrogen
water
carbonate
molecule
molecule
Single Replacement
e. HCl
+
NaOH
hydrogen
sodium
chloride
hydroxide
molecule
compound


Ca(OH)2
a compound of
to form calcium hydroxide
+
H2
hydrogen molecule
CO2
carbon dioxide
molecule
HOH
+
NaCl
water
sodium chloride
molecule
compound
3.
Write the word reactions for those mentioned earlier in the motivation part,
then the balance chemical equations. Students might find this a little difficult.
You can provide the equations and let them do the balancing.
4. You may tell the student the type each reaction belong to differentiate them
from one another but do not give this too much emphasis. They will take this up
in detail in their third year.
5. You may give the chemical equations of some reactions taken up in previous
lesson.
You may stop at this point. Ask the students to read the procedure for Activity
10-3 and bring at least one medium-sized rock and a bottle of vinegar for the
group’s use.
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6. Perform Activity 10-3. Acid rain is a major pollutant in the world today. This
activity designed to show the effect of acid rain on limestone rock. If limestone
is not available, you may use marble chips. You can get these from stores
selling construction materials.
7. Conduct a post-discussion on the observations and relate it to the effect of acid
rain in the environment particularly on statues and buildings.
D. Discussion
1. Chemical equations show:
a.
b.
c.
d.
the reactants which enter into a reaction;
the products which are formed by the reaction;
the amount of each reactant used and each product formed.
that the sign, , means “yields” or “forms” and shows the direction of the
reaction.
2. There are some important principles in writing chemical equations:
a. every chemical compound has a formula which cannot be changed;
b. every atom used as reactant must be accounted for in the product. This is
an application of the Law of Conservation of Matter, which states that in a
chemical reaction, atoms are neither created nor destroyed.
3. Some things to remember about writing equations:
a. the diatomic elements when they stand alone are always written with the
subscript 2, e.g. H2, N2, O2, F2, Cl2, Br2, I2.
b. see to it that each formula in the equation is correct before attempting to
balance the equation.
c. balance the equation by placing coefficients in front of the formulas to
insure the same number of atoms of each element on both sides of the
arrow.
4. There are four types of chemical reactions:
a. Combination – two or more elements or two or more compound combine to
form a single product.
b Decomposition – A single compound decomposes or breaks down into its
constituent elements or compounds
d. Single Replacement – A compound is broken down by an element, either a
stronger metal or nonmetal which replaces the metal in the compound.
e. Double Replacement – two pairs of different compounds combine and
results in the exchange of partners in between pairs.
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5. Equations for the chemical changes observed in Activity 7-2 and 9-2.
CuSO45H2O
copper sulfate
pentahydrate
C12H22O11

sucrose (sugar)

CuSO4
+
anhydrous
copper sulfate
12C +
carbon
CaCO3 + 2 CH3COOH
calcium
acetic
carbonate
acid
(limestone)
(vinegar)

5H2O
water
11H2O
water
Ca(CH3COO)2
calcium
acetate
+ H2CO3
hydrogen
carbonate
(carbonic acid)
You may stop at this point. Ask the students to read the procedure for Activity
10-3 for next day’s activity.
6. Acid rain is a broad term used to describe several ways that acids fall out of
the atmosphere. A more precise term is acid deposition, which has two parts:
wet and dry.
Wet deposition refers to acidic rain, fog, and snow. As this acidic water flows
over and through the ground, it affects a variety of plants and animals. The
extent of effect depends on many factors, including how acidic the water is, the
nature of the soils involved, and the types of fish, trees, and other living things
that rely on the water.
Dry deposition refers to acidic gases and particles. About half of the acidity in
the atmosphere falls back to earth through dry deposition. The wind blows
these acidic particles and gases onto buildings, car, homes, and trees.
Dry deposited gases and particles can also be washed from trees and other
surfaces by rainstorms. When that happens, the runoff water adds those acids
to the acid rain, making the combination more acidic than the falling rain alone.
Scientists discovered, and have confirmed, that sulfur dioxide (SO2) and
nitrogen oxides (NO and NO2) are the primary causes of acid rain. Its sources
are burning of fossil fuels like coal ,gasoline, and natural gas.
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Acid rain occurs when these gases react in the atmosphere with water, oxygen,
and other chemicals to form various acidic compounds like sulfuric acid and
nitric acid. Sunlight increases the rate of most of these reactions.
SO2 + H2O  H2SO3
sulfurous acid
2SO2 + O2  2 SO3;
SO3 + H2O  H2SO4
sulfuric acid
2 NO + O2  2 NO2
2NO2 + H2O  HNO2 + HNO3
nitrous acid nitric acid
NO2 + [OH]-  HNO3
Acid rain looks, feels, and tastes just like clean rain. The harm to people from
acid rain is not direct. Walking in acid rain, or even swimming in an acid lake,
is no more dangerous than walking or swimming in clean water. However, the
pollutants that cause acid rain (sulfur dioxide (SO2) and nitrogen oxides (NOx)
also damage human health.
These gases interact in the atmosphere to form fine sulfate and nitrate particles
that can be transported long distances by winds and inhaled deep into people's
lungs.
Many buildings and monuments are made of stone, and many buildings
use stone for decorative trim.
Granite is now the most widely used stone for buildings, monuments, and
bridges. Limestone is the second most used building stone. It was widely used
before Portland cement became available in the early 19th century because of
its
uniform color and texture and because it could be easily
carved
Because of their composition, some stones are more likely to be damaged by
acidic deposition than others. Granite is primarily composed of silicate
minerals, like feldspar and quartz, which are resistant to acid attack. Sandstone
is also primarily composed of silica and is thus resistant.
Limestone and marble are primarily composed of the mineral calcite (calcium
carbonate), which dissolves readily in weak acid; in fact, this characteristic is
often used to identify the mineral calcite.
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Acid precipitation affects stone primarily in two ways: dissolution and alteration.
When sulfurous, sulfuric, and nitric acids in polluted air react with the calcite in
marble and limestone, the calcite dissolves. In exposed areas of buildings and
statues, we see roughened surfaces, removal of material, and loss of carved
details. Stone surface material may be lost all over or only in spots that are
more reactive.
E.
Evaluation
1.
Give the number of atoms of elements in each formula given in the table
below:
Fomula
Number of Atoms of
C
H
O
Cu
Ca
N
S
Si
CH3COOH
CuSO45H2O
HNO3
Ca(OH)2
SiO2
NH4NO3
2. Examine the chemical equations below:
a) Compare the number of atoms in the reactant side and in the product side.
b) Write YES if the number of atoms of the elements are equal on both sides
and NO if the number of atoms of the elements are not equal on both
sides,
c) If your answer is no, explain why.
2.1
2.2
2.3
2.4
Zn + CuSO4  ZnSO4 + Cu
KClO3  KCl + O2
CO + O2  CO2
HNO3 + NaOH  NaNO3 + HOH
IV. Agreement/Assignment
182
1.
What is Waste Recycling? What are some of the methods followed in waste
recycling?
2.
Name some of the contributions of Filipino and Foreign scientists in waste
recycling.
BSE-Department of Education
Student Activity Sheet 10.4
Simulating Acid Rain
Materials
vinegar
medicine droppers
watch glass
medium-sized limestone rock
small piece of basalt rock
hammer
Procedure
1. Place small pieces limestone in a watch glass. Place a piece of colored paper under the
watch glass for better observation.
2. With a medicine dropper, place a few drops of vinegar onto the limestone. Describe your
observations.
3. Continue dropping vinegar in a constant stream to simulate rain. What happens to the
rock? Compare your observations on this rock with that in step 2.
Data
Material
observed
Initial observations
Final Observations
Questions
1.
2.
3.
4.
5.
What happens when vinegar is combined with limestone?
What were the indications that a chemical change took place?
Write the balanced equations for the reactions.
Discuss how rain becomes acidic.
Explain how acid rain destroys statues and buildings.
Generalization
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