Download Unit 2 - Classifying Matter

Unit 2 - Classifying Matter
Time Frame
Competencies
C1.
C2.
C3.
2 weeks
Demonstrate skill in identifying chemical systems and classification of matter.
Appreciate understanding of elements and compounds present in daily life.
Demonstrate simple techniques in the preparation, separation, and purification of
mixtures.
IDENTIFICATION OF CHEMICAL SYSTEMS
Time Frame: 3 sessions
I. Learning Objectives
At the end of the session, the students must be able to:
1. Describe a pure substance and a mixture;
2. Observe and record data;
3. Make operational definitions of chemical systems, pure substances, and mixtures;
4. Recognize such chemical systems around them.
II. Subject Matter
A. Topic: Classification of chemical systems; purity of substances
B. References
1. Department of Education, Culture and Sports. (1991). Science and Technology III.
Quezon City: Book Media Press, pp. 29-40.
2. Brown, Theodore L., LeMay, H. Eugene Jr., and Bursten, Bruce E., (2000).
Chemistry the Central Science. New Jersey: Prentice Hall, pp. 5-11.
3. Hill John W., and Kolb, Doris K.(1995). Chemistry for Changing Times, 7th
Edition. London: Prentice Hall International, pp. 17-20.
4. Franco, Aurora A., et. al. Interactive Chemistry. pp. 28 - 29.
C. Materials
Water
Vinegar
Cooking Oil
Sugar
Salt
Soy sauce
Calamansi juice
Shampoo
Syrup
Buttons, cork, coin, etc.
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III. Learning Tasks
A. Recall and Motivation
1. Ask the students to write on a piece of paper the first word that comes to mind
when they hear the word "matter". The words are then posted on the board. The
following terms are written on colored cartolina: elements, compounds, colloids,
substances, solutions, mixture, paper, food, carbon, oxygen, and air.
2. “Density Column Demonstration”
Set-up:
Note the layering of the liquids (oil, colored water, shampoo, syrup).
Different solids are dropped into the column and the students are
asked to observe what happens. Solids that may be dropped:
buttons, plastic chips, bolts, screws, wood chips, etc.
B. Lesson Proper
1. Activity: “Chemical Systems” (SAS 2-01a)
Objectives: At the end of this activity, the students should be able to:
 Differentiate homogenous and heterogeneous systems;
 Give the operational definition for a homogeneous system;
 Record and observe data; and
 Make inferences.
Materials: soy sauce
garlic in Vinegar
cooking oil in water
mud and water
filtered calamansi
flour extract & cornstarch
syrup
salt and water
Procedure:
1. Put each of the materials in separate test tubes and number them 1 to 8.
2. Observe their properties in terms of color, odor, phase, texture and
appearance.
3. Record and tabulate your observations and classify the chemical system.
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2. Discussion/ Concept Formation
a. Description of the Chemical Systems
Chemical System
Observations
Classification
1. soy sauce
1 dark liquid
Homogeneous
2. garlic in vinegar
1 liquid + 1 solid
Heterogeneous
3. cooking oil in water
2 liquids:
Heterogeneous
1 yellow, 1 colorless
4. mud and water
1 solid + 1 liquid
Heterogeneous
5. filtered calamansi
1 yellow liquid
Homogeneous
6. flour and cornstarch
1 white solid
Homogeneous
7. syrup
1 colored liquid
Homogeneous
8. salt water solution
1 colorless liquid
Homogeneous
b. Answer the following guide questions:
i. How many phases do you see in each set-up?
ii. Which systems are homogeneous? Heterogeneous?
iii. How would you define a homogeneous system? a heterogeneous
system? Answer: A homogeneous system is a one-phase system
where all parts show the same properties all throughout; a
heterogeneous system is has one or more phases in the system and
each part retains its original properties.
YOU MAY END SESSION 1 AT THIS POINT.
3. Activity: “Mixtures & Pure Substances” (SAS 2-01b)
Objective: At the end of this activity, the student should be able to differentiate
between pure substances and a mixture.
Materials. Salt
Water
Evaporating dish
Match
Tripod
Wire gauge
Alcohol Lamp
Procedure:
1. Get a small amount of salt and a glass of water. Observe their properties.
2. Pour a small amount of water into the evaporating dish and dissolve the salt in
it.
3. Evaporate the solution using a water bath until almost all of the water has
evaporated; the evaporating dish aside to complete the evaporation process.
4. Observe the contents after the evaporating dish has cooled.
4. Discussion/ Concept Formation
a. Answer the following questions:
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i. What is left of the solution? Compare its properties with the original
salt.
ii. Were you able to get the salt from the solution? How? What kind of
matter is salt?
iii. Where did the water go? What type of matter was left in the dish?
iv. Which of the systems is a mixture? Why?
v. Define a (1) substance and (2) mixture. (A substance is made up of
only one kind of molecule and cannot be separated by physical means.
A mixture is made up of 2 or more kinds of molecules, which can be
separated by physical means.)
b. Application: Describe the production of salt by evaporation. Is the salt
produced here different from what has been produced in the laboratory?
YOU MAY END SESSION 2 AT THIS POINT.
C. Generalization
1. Homogeneous systems are one-phase systems; all parts of the systems show the
same characteristics all throughout. A heterogeneous system is a one ore more
phase system; the parts retain their original properties.
2. A substance is made of only one kind of molecule; a mixture is made of 2 or more
kinds of molecules.
3. Table of Mixtures
Type of Mixture
Filterability
Particle Size
Degree
Settling
Tyndall Effect
solutions
(ex. salt solution)
colloids
(ex. starch &
water)
not
filterable
slight
filterability
smallest particle size
does not
settle
slightly
dispersed
NA
suspensions
(ex. starch &
water)
very
filterable
particle are bigger than
that of solutions but
smaller than
suspensions
biggest particle size
Particles
settle at the
bottom
Tyndall effect
was observed
NA
D. Application / Valuing
How is this kind of knowledge useful in your life? In society? In the environment?
E. Evaluation
a. Differentiate the types of mixtures: solutions, colloids and suspensions.
b. Give other examples of mixtures and describe how each may be classified.
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