Download Chemical Properties - Michigan State University

TE 407: Lesson and Unit Plan Guide
Name: Faye Blumberg
Mentor Teacher: Dan Anibal
Partner: Abigail I
School: Bath Middle School
Part I: Information about the Lesson or Unit
Topic:
Subject: Chemistry
Unit Topic: Properties of Matter
Lesson Topic: Chemical Properties
Type of Class
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Grade level(s): 7 basic
Type of school: Rural
Tracking level: College bound
Abstract – trying to accomplish or what our mentor teacher was asking us to do
In this lesson I will give a brief overview to my students about the differences of chemical
and physical changes, which many might already know. I want to ask questions to get the
students thinking about which changes are physical and which ones are chemical. The
chemical change will be my lead into the lesson of chemical properties. I want them to be
able to describe that a chemical property are any changes that become evident during a
chemical reaction. I want them to briefly try to think of chemical properties that could help
classify a substance- pH, flammability, acid-base indicators, and reactivity. Then the students
will perform the lab. At the end of the lab they should be able to explain the difference
between physical and chemical changes. They should be able to answer the differences
between the two and be able to define both changes.
Part II: Clarifying Your Goals
Big Ideas – bigger idea of content…unit level
Physical changes are changes that only affect the physical properties of a substance. For
example, phase changes are physical properties. On the contrary, chemical changes produce new
substances, which have different properties, compared to the old substances. The composition is
a chemical change is altered. This occurs when you burn a substance, mixing an acid and a base,
or when you observe rusting or rotting. The process that produces a chemical change is known as
a chemical reaction. A chemical reaction is composed of reactants and products. Many chemical
reactions are irreversible. The chemical reaction only goes one way. There are many ways to
recognize a chemical change. The substance may produce bubbles (gas), change color, have an
odor, produce a precipitate, or absorb/release energy. However, there are always exceptions to
these generalizations. Energy is needed in many chemical changes in order to break bonds.
Atoms in a chemical process are never lost but instead are rearranged. Chemical processes can be
tested on a daily bases. How flammable is sand? How about sugar? What about salt?
Understanding chemical properties can help explain how new substances are formed. We
can classify substances by their chemical properties. We can measure pH, flammability,
reactivity (against other chemicals), electronegativity etc. We can also use acid-base indicators to
titrate substances and observe when they have been neutralized.
On the contrary, there are also physical properties. These properties can be seen or
measured with out changing the composition. Such examples may be absorption, density, length,
mass, etc. These properties can be determined with out changing the composition of the
substance.
Experiences, Patterns, and Explanations
Observations or experiences
(examples, phenomena, data)
Patterns (laws,
generalizations, graphs,
tables, categories)
Explanations (models,
theories)
Incoming Ideas
Chemical changesburning, rotting, chemical reactions,
photosynthesis
Physical changescutting, boiling, cooling, changing
pressure, changing states
Dissolving?- students may not know how
to classify dissolving
changing from solid to liquid to gas
(phase changes) are just physical changes
sugar dissolves
we can still get the sugar back if we
dissolve all the water
crushing the sugar or dissolving the sugar
wont change its taste
crushing the sugar wont change its
chemical makeup
Chemical changes are from
chemical reactions – new
substances are formed
Chemical changes may look
different, have a different smell,
or color.
Goal/Target EPEs
Physical changes can usually go
in reverse- energy may be needed
Chemical changes are separate
changes in substances
(misconception)
Physical changes only effect
physical properties
heating the sugar creates a chemical
changethe sugar is burnt and changes color
the burnt sugar produces a certain odor
Chemical changes usually can’t
be undone (or go in reverse)
Chemical changes are just
rearrangements of atoms.
Atoms are not created or
destroyed.
often can detect a chemical change by a
change in color/odor/ph/precipitation
In a chemical change a new
substance is usually formed
The arrangement of atoms is
through breaking or making
bonds.
Application: Model-based Reasoning – using models/theories to explain experiences
Inquiry: Finding and Explaining Patterns in Experience
Objectives for Student Learning
Michigan Objective(s)
1. P.PM.07.11 Classify substances by their chemical properties
(flammability, pH, acid-base indicators, reactivity).
2. P.CM.07.22 Compare and contrast the chemical properties of a
new substance with the original after a chemical
change
Specific Lesson Objective(s)
1. When did the sugar go through a physical change? What properties remained the same
and what changed? When did the sugar go through a chemical change? How do we know?
2. Be able to discuss which changes are usually irreversible and which are reversible. How
could we get the sugar back to its original form after crushing it? How about after dissolving
it? Burning it?
Problem: Ask the students what is occurring when a marshmallow burns. Demonstrate
Model: Ask what kind of change is occurring when something burns in general. What
changes with the substance? Give them the example of a metal rusting and help guide them
through what happens.
Coach- Ask questions regarding chemical and physical changes. How can we tell the
difference? Is one reversible? Give a brief overview of the lab and be ready to answer any
questions
Fade- Have the students reform the lab
Part III: Classroom Activities
Materials
Each group will also get the lab write up, “Observing Changes in Matter.”
Presentation materials :
Since my students are watching a demo and doing a lab I don’t want to take too much time doing
presentation (a powerpoint etc). I will however explain things slowly through lecture give
examples and ask for any questions. I think this objective is learned best hands on.
Copied materials (Handouts, worksheets, tests, lab directions, etc.):
I have copies of the labs but have no scanner. I copied them from Mr. Anibal before I left school
today- I can get you these in person
Pages in textbook: Book: Glencoe Science- Chemistry, National Geographic
Pages: 36-38
Laboratory materials: For the teacher or the class as a whole:
Marshmallow and a match
For each laboratory station:
Each group will need the following:
4 cubes of sugar
Glass of water
Spoon
Mortar & pestle
Bunsen burner
Test tube
Tongs
Activities
Introduction (7-10 minutes)
• Make conceptual connections with previous lessons- From what Mr. Anibal has said, this is
their first intro into physical and chemical changes. We’re using this lab as a guide to further
discuss chemical properties of a substance. This is more so the gateway into the objective gave
me.
I want to ask the students what they know about physical and chemical changes. How can we tell
which is occurring? Can you give examples of each? Which are reversible?
I want to discuss the ways we can classify chemical reactions through their chemical processes.
How flammable is a substance?? Does a substance dissolve in water?
The students should be able to explain and connect the fact that you can classify substances by
their chemical properties and have them provide examples (maybe not after this intro lab, but
that is the “bigger goal”)
To get them started about thinking on the right track I plan on show a demonstration. The
marshmallow will burn. This will spark their interest (hopefully) and get them engaged on the
lesson.
I’d then introduce the lab to the students and go through what they will be doing briefly. I also
want to warn them not to swallow the burnt sugar, but may taste it. They should also be very
careful while using the burner. Glass will not look hot.
Main Teaching Activities 20-25 min)
The main activity is having the students performing the lab. They first crush up sugar and
see that it still has the same properties. They then put sugar in water watch it dissolve and
explain what is occurring. After, they have the sugar go through a chemical change by burning it.
Through out the lab they are using their senses to see, taste, touch the sugar in all forms. They
will look at the size, shape, color, hardness, and texture to see how it changes depending on the
physical or chemical change.
The students will be performing the lab. The lab is pretty self-explanatory and has key
questions to answer throughout. I will be walking around, answering any questions, as well as
giving safety cautions.
The student’s references materials are basically each other, the lab, and myself. The lab
walks them through key questions to think about and the conclusions to draw.
Conclusion (7-10 minutes)
After the students have finished performing the lab, they should clean up and get their lab
area in order. After, I want the students to regroup and as a class discuss the lab. I want to engage
a discussion of what the students learned about classifying substances based on chemical
properties. There are two critical thinking questions at the end of the lab. Having students answer
these questions can be helpful to see which students got the “big ideas.” With that being said I
don’t want to give too much of the answers away by a discussion. I want to lead the students on
the right track but still having them draw their own conclusions about chemical changes,
physical changes, and chemical processes.
Part IV: Assessment of Students
Developing Assessment Tasks
The major assessment for my lesson is the lab worksheets they complete and the lessons
they answer. There are questions that are embedded throughout the lab as well as questions to
answer after the lab has been completed.
There are many questions that the students cannot get wrong. These are questions about
what is occurring in the lab.
How has the sugar changed? (asked after the physical AND chemical change)
Is the sugar still present?
How are the physical and chemical changes different?
How would you classify a physical change? What about a chemical change?
I want to discuss and ask a question also about chemical processes, however I still need
time to think about questions that they’ll be able to answer after performing this lab.
I think I’ll learn from incorrect answers. By seeing what they were confused on, I can
revamp my next lesson to clear up any misconceptions. I think if students don’t understand the
science behind chemical and physical changes, they wont really understand the concept.
Knowing that chemical reactions produce a chemical change is pretty important. Its also very
important that the students understand that atoms are not created or destroyed. The atoms and
molecules are rearranged. This idea can later build by looking at reactions, rates, precipitates,
etc.
The task is relevant to the objective in the sense that it’s a gateway to learning about
chemical processes. In order to be able to explain chemical processes, students must first be able
to explain chemical changes. The chemical change concepts will then help the students make
connections to chemical properties, i.e. The sugar melted, that means it has a chemical property
of flammability.
The lab the students are performing is very clear-cut. It has the students answer questions
and go through the lab step by step. It’s a very good walk through about how the students can
differentiate physical and chemical changes.
The theory questions at the end of the lab have students relate the lab to patterns they
should have picked up through out the lab.
Compare the changes in the sugar. How are they different?
How do you define a physical change? How would you define a chemical change?
With the answers to these questions I can see what concepts they picked up on. The only
thing I’m worried about is the fact the students may not really understand physical/chemical
changes, but just write down what they remember from my intro and class discussion. I think this
will have to be determined on an individual basses and after the lab has been preformed.