Chemical Reactions Lesson
Author: Alison Hapka, Elkton High School, Cecil County Public Schools
Background Information
Subject:
Identify the course the unit will
be implemented in.
Grade Band:
Identify the appropriate grade
band for the lesson.
Duration:
Identify the time frame for the
unit.
Overview:
Provide a concise summary of
what students will learn in the
lesson. It explains the unit’s
focus, connection to content, and
real world connection.
Background Information:
Identify information or resources
that will help teachers
understand and facilitate the
challenge.
STEM Specialist
Connection:
Describe how a STEM Specialist
may be used to enhance the
learning experience. STEM
Specialist may be found at
http://www.thestemnet.com/
This lesson could be used in a high school chemistry course in the unit on chemical reactions.
9-12
Two ninety minute periods.
Students will observe and collect data on the mass of the reactants vs. the products of a simple
chemical reaction to investigate the conservation of mass during the reaction. This exploration of a
reaction in a flask with the top covered by a deflated balloon to see if mass is conserved during a
chemical reaction. The liquid remaining in the flask will be heated to evaporate the water and yield
the mass of the solid that precipitates. Students will demonstrate their understanding by developing
a concept cartoon that demonstrates the movement of atoms before, during, and after a chemical
reaction.
When a chemical reaction occurs, bonds between atoms are broken and formed which results in a
transfer of energy but the same number of atoms of each element that were present before the
reaction will also be present after the reaction and therefore the mass of the total reactants will
equal the mass of the total products.
A STEM Specialist can enhance the learning experience by engaging students in applied learning
experiences that demonstrate the importance of understanding chemical reactions and making
relevant connections to the workplace.
Enduring Understanding:
Identify discrete facts or skills to
focus on larger concepts,
principles, or processes. They
are transferable - applicable to
new situations within or beyond
the subject.


Mass is conserved in a chemical reaction.
Energy is required to break bonds between the elements.
Page 1 of 10
Chemical Reactions Lesson
Essential Questions:
Identify several open-ended
questions to provoke inquiry
about the core ideas for the
lesson. They are grade-level
appropriate questions that
prompt intellectual exploration of
a topic.
Student Outcomes:
Identify the transferable
knowledge and skills that
students should understand and
be able to do when the lesson is
completed. Outcomes must align
with but not limited to Maryland
State Curriculum and/or national
standards.
1.
2.
3.
4.
Background Information
How does the total mass of the products of a chemical reaction compare to the total mass of
the reactants of the reaction?
How does the total number of atoms of the products of a chemical reaction compare to the
total number of atoms of the reactants of the reaction?
How does the total number of molecules of products of a chemical reaction compare to the
total number of molecules of the reactants of the reaction?
How can one demonstrate that mass is conserved during a chemical reaction?
Students will be able to:
 gather qualitative and quantitative data before, during, and after a reaction to compare the
mass of the reactants and products of a chemical reaction.
 calculate the necessary mass of the second reactant to complete a chemical reaction.
 calculate the theoretical yield of each of the products of a chemical reaction.
 measure the actual yield of each of the products of a chemical reactions.
 calculate the percent yield of each of the products of a chemical reaction.
 create a concept cartoon that represents what is happening to the atoms before, during, and
after the chemical reaction.
Product, Process,
Action, Performance,
etc.:
Identify what students will
produce to demonstrate that
they have met the challenge,
learned content, and
employed 21st century skills.
Additionally, identify the
audience they will present
what they have produced to.
Standards Addressed in
the Unit:
Identify the Maryland State
Curriculum Standards addressed
in the unit.
Students will create a concept cartoon that represents what is happening to atoms before, during,
and after the chemical reaction. The cartoon will represent atoms, energy transfer, chemical bonds,
and the kinetic energy of the moving atoms and molecules.
Next Generation Science Standards:
HS-PS1 Matter and It’s Interactions
HS-PS1-7.Use mathematical representations to support the claim that atoms, and therefore
mass, are conserved during a chemical reaction.
Page 2 of 10
Chemical Reactions Lesson
Background Information
Common Core Reading in Science and Technical Subjects:
RST.11-12.3 Follow precisely a complex multistep procedure when carrying out experiments, taking
measurements, or performing technical tasks; analyze the specific results based on explanation in
the text.
Common Core Writing in Science and Technical Subjects:
WHST.11-12.2 Write informative/explanatory texts, including the narration of historical events,
scientific procedures/experiments, or technical processes.
Suggested Materials and
Resources:
Identify materials needed to
complete the unit. This includes
but is not limited to websites,
equipment, PowerPoints, rubrics,
worksheets, and answer keys.
Equipment: (for each lab group of 2-3 students)
• erlenmeyer flask
• balance
• weighing dish
• two reactants
• balloon
For the reactants there are many different chemical reactions that can be used for this investigation
and calculation. One good combination is acetic acid (vinegar) and sodium bicarbonate (baking
soda).
Website:
Concept cartoon example:
http://www.iupac.org/fileadmin/user_upload/news/2013/cartoon_prizewinners/cartoon13_Bilb
rey.pdf
People, Facilities:
STEM Specialist
Materials (rubrics, worksheets, PowerPoints, answer keys, etc.):
 Chemistry Concept Cartoon Rubric
 An alternate concept cartoon rubric can be found here >>> Cartoons – An Alternative
Learning Assessment
Page 3 of 10
Chemical Reactions Lesson
Learning Experience
5E Component
Identify the 5E
component addressed for
the learning experience.
The 5E model is not
linear.
☐Engagement
x Exploration
☐Explanation
☐Extension
☐Evaluation
Details
Materials:(for each lab group of 2-3 students)
• erlenmeyer flask
• balance
• weighing dish
• two reactants
• balloon
• hot plate
• hot hands or flask tongs
For the reactants there are many different chemical reactions that can be used for
this investigation and calculation. One good combination is acetic acid (vinegar)
and sodium bicarbonate (baking soda). If another reaction is selected, check the
safety of both the reactants and products, and be sure that evaporating the liquid
solution that remains by using a hot plate will not product a hazardous condition in
the laboratory.
Preparation: Be sure to test out the ratio of acetic acid to sodium bicarbonate to
make sure the gas produced is enough to partially fill the balloon but not pop the
balloon off of the flask. Students will be calculating the quantities of each reactant
to use, but depending on the concentration of acetic acid you are using, you need
to limit the quantity of one of the two reactants to avoid having the balloon overfill
and pop off of the flask.
Science and
Engineering
Practices
☒Asking questions (for
science) and defining
problems (for
engineering)
☐Developing and using
models
☒Planning and carrying
out investigations
☐Analyzing and
interpreting data
☒Using mathematics and
computational thinking
☐Constructing
explanations (for
science) and designing
solutions (for
engineering)
Facilitation of Learning Experience: Introduce students to the erlenmeyer flask if
students have not previously used them, and demonstrate the technique of putting ☐Engaging in argument
an empty balloon over the mouth of the flask before mixing the chemicals. The
Page 4 of 10
Chemical Reactions Lesson
Learning Experience
5E Component
Identify the 5E
component addressed for
the learning experience.
The 5E model is not
linear.
Details
choice of whether to put the liquid or solid reactant in the balloon before mixing
should be left to the students.
Science and
Engineering
Practices
from evidence
☒Obtaining, evaluating,
and communicating
Before beginning the investigation, have students predict what they think will
happen to the total mass of the container during the reaction and after the reaction information
is complete. To test their prediction, students will measure and record the mass of
each piece of their apparatus as well as their reactants before the reaction, and
monitor the mass of the entire system during the reaction. Then using the mass of
one reactant, calculate how much of the second reactant they will use for their
reaction.
After the reaction, students should again mass the components of the reactions.
To determine the mass of the gas collected, students can carefully tie off the
balloon and find the mass of the filled balloon. Some of the gas will also be in the
top of the flask which students can discuss as part of the error analysis of the lab.
To separate the water from the dissolved solid, heat the solution on a hot plate.
When the liquid is mostly evaporated be prepared to remove the flask from the hot
plate so that the hot solid does not pop out of the flask or burn. Be sure to use
either flask tongs or hot hands to remove the hot flask from the hot plate and turn
off the hot plate once the flask has been removed.
For best results, student lab groups should repeat the experiment three times.
Transition: The data from this exploration lab will be used in the analysis in the
next portion of the lab.
Page 5 of 10
Chemical Reactions Lesson
Learning Experience
5E Component
Identify the 5E
component addressed for
the learning experience.
The 5E model is not
linear.
☐Engagement
☐Exploration
x Explanation
☐Extension
☐Evaluation
Details
Science and
Engineering
Practices
Materials: Students will need access to their lab data.
☒Asking questions (for
science) and defining
Preparation: Practice a few stoichiometry problems to prepare for the introduction
problems (for
to this technique.
engineering)
Facilitation of Learning Experience: Guide students through the writing and
balancing of the chemical equation for the reaction that they used in their
investigation. For acetic acid and sodium bicabonate the equation is:
☐Developing and using
models
CH3COOH + NaHCO3 → NaCH3COO + CO2 + H2O
☐Planning and carrying
out investigations
Next, have the groups use their lab data to determine:
What is the theoretical yield of carbon dioxide gas from my reactants?
What is the theoretical yield of sodium acetate from my reactants?
What is the theoretical yield of water from my reactants?
What was the actual yield of sodium acetate?
What was the actual yield of water?
What was the actual yield of carbon dioxide?
Compare the theoretical and actual yield for each of the three products to
calculate the percent error for your experiment.
8. Discuss your results and whether or not they make sense.
9. How did the total mass of the reactants and apparatus compare to the total
mass of everything after the reaction?
10. How many molecules of acetic acid did you use in your reaction?
11. How many molecules of sodium bicarbonate did you use in your reaction?
12. How many molecules of water theoretically formed in your reaction?
1.
2.
3.
4.
5.
6.
7.
☒Analyzing and
interpreting data
☒Using mathematics and
computational thinking
☒Constructing
explanations (for
science) and designing
solutions (for
engineering)
☐Engaging in argument
from evidence
Page 6 of 10
Chemical Reactions Lesson
Learning Experience
5E Component
Identify the 5E
component addressed for
the learning experience.
The 5E model is not
linear.
Details
13. How many molecules of carbon dioxide theoretically formed in your
reaction?
14. How many molecules of sodium acetate theoretically formed in your
reaction?
15. How many atoms of each element were present in the reactants for the
reaction?
16. How many atoms of each element were present in the products for the
reaction?
17. How does the number of total molecules present in the reactants compare
to the total number of molecules present in the products compare?
18. How does the number of total atoms present in the reactants compare to
the total number of atoms present in the products compare?
19. How does the number of atoms of each element present in the reactants
compare to the number of atoms of the same element in the products?
20. Was the number of molecules conserved in the reaction?
21. Was the mass conserved in the reaction?
22. Was the number of atoms conserved in the reaction?
Science and
Engineering
Practices
☒Obtaining, evaluating,
and communicating
information
Transition: Once the data has been analyzed, students will next use their lab
results to create a three segment concept cartoon about what is happening on a
microscopic scale during the reaction.
Page 7 of 10
Chemical Reactions Lesson
Learning Experience
5E Component
Identify the 5E
component addressed for
the learning experience.
The 5E model is not
linear.
☐Engagement
☐Exploration
☐Explanation
x Extension
x Evaluation
Details
Materials:
 Colored pencils or markers
 Rulers
 Chemistry Concept Rubric
Science and
Engineering
Practices
☐Asking questions (for
science) and defining
problems (for
engineering)
Preparation: Review examples of concept cartoons and select one to share with
☒Developing and using
the class. Make sure that the cartoon that depicts a concept that has been already
covered with this class, but not one that will fit the assignment. Here is a possible models
candidate (many others will be revealed by a google search of “chemistry concept
☐Planning and carrying
cartoons”):
out investigations
http://www.iupac.org/fileadmin/user_upload/news/2013/cartoon_prizewinner
☐Analyzing and
s/cartoon13_Bilbrey.pdf
interpreting data
Facilitation of Learning Experience: Review the reaction students investigated ☐Using mathematics and
computational thinking
in the lab. Introduce the concept cartoon project and distribute the rubric. Inform
students that they will create a concept cartoon that represents what is happening
☒Constructing
to the atoms before, during, and after the chemical reaction. The cartoon will
represent atoms, energy transfer, chemical bonds, and the kinetic energy of the
explanations (for
moving atoms and molecules.
science) and designing
solutions (for
After students prepare a rough draft of their cartoons, have them do a peer review
engineering)
using the rubric and write three clarifying questions they would like the other
student to address in their cartoon. Then have students revise their cartoons, and ☐Engaging in argument
do a gallery walk of the finished work by all students. Facilitate a class discussion from evidence
focusing on what was happening during the reaction and how that was best
depicted and most accurately represented in the cartoons produced by the class.
Page 8 of 10
Chemical Reactions Lesson
Learning Experience
5E Component
Identify the 5E
component addressed for
the learning experience.
The 5E model is not
linear.
Details
Science and
Engineering
Practices
☒Obtaining, evaluating,
and communicating
information
Page 9 of 10
Chemistry Concept Cartoon Rubric
(prepared using rubi star rubric generator)
Category
4
3
2
1
Title is informative
and centered.
The title is
incomplete and does
not clearly indicate
what organism is
pictured.
Almost all assigned
details (at least
85%) have been
added. The details
are clear and easy
to identify.
Almost all assigned
details (at least
85%) have been
added. A few details
are difficult to
identify.
Fewer than 85% of
the assigned details
are present OR
most details are
difficult to identify.
Accuracy
(12 points)
95% or more of the
assigned structures
are drawn
accurately and are
recognizable. All
assigned structures
are labeled
accurately.
94-85% of the
assigned structures
are drawn
accurately and are
recognizable. All
assigned structures
are labeled
accurately.
94-85% of the
assigned structures
are drawn
accurately and are
recognizable. 9485% of the assigned
structures are
labeled accurately.
Less than 85% of
the assigned
structures are drawn
AND/OR labeled
accurately.
Labels
(8 points)
Every item that
needs to be
identified has a
label. It is clear
which label goes
with which structure.
Almost all items
(90%) that need to
be identified have
labels. It is clear
which label goes
with which structure.
Most items (75-89%)
that need to be
identified have
labels. It is clear
which label goes
with which structure.
Less than 75% of
the items that need
to be identified have
labels OR it is not
clear which label
goes with item.
Title
(4 points)
Title is informative, Title is informative
centered, and larger and larger than
than other text.
other text.
All assigned details
Drawing Details (12 have been added.
The details are clear
points)
and easy to identify.
An alternate rubric can be found here >>> Cartoons – An Alternative Learning
Assessment