Name: _____________________________________________
Date: _________________________
TP: __________
CW: Equilibrium Unit Review
Chemistry
Entrance Ticket Review:
The chemical equation which your company uses to make its different colors of icing dye for turkey cookies
is below.
𝐹𝑒 3+ + 𝑆𝐶𝑁 − ↔ 𝐹𝑒𝑆𝐶𝑁 2+
(yellow)
(clear)
(dark red)
You want to create a yellow dye if given a test tube that has 1 mL of FeSCN2+ in it.
a. Which chemical do you need more of to create a yellow dye? ____________________________
b. Which direction should you shift equilibrium to create more of a yellow color? ______________________
c. Looking at the equation, what are three ways you can shift equilibrium the way you want?
a. __________________________________________________________
b. __________________________________________________________
c. __________________________________________________________
d. From the lab, do you heat or cool the solution to lighten the color? _________________________________
e. Create a claim as to how you can turn a test tube with 1 mL of FeSCN2+ yellow.
f. Which test tubes support this claim and what happened in them?
g. What is the general statement about chemical equilibrium that allows us to change the color of the
solution?
h. What did you do incorrectly on the entrance ticket?
BE YOUR BEST SELF !
1. There is an answer key attached to this review. Why is an answer key attached to this review? What
does an answer key allow you to do? How should you study?
Level: _________ What do you need to do differently to improve? _________________________________________________
2. Your younger brother is studying science in third grade. He says that all chemical reactions proceed
until the reactants have been completely converted into products. Is he correct? What would you
say to him?
Level: _________ What do you need to do differently to improve? _________________________________________________
3. Your older sister is studying chemistry in college. She says equilibrium occurs when there are the
same number of reactants as there are products. Is she correct? What would you say to her?
Level: _________ What do you need to do differently to improve? _________________________________________________
4. Explain what equilibrium is.
Level: _________ What do you need to do differently to improve? _________________________________________________
5. What do we mean when we say that equilibrium is dynamic?
Level: _________ What do you need to do differently to improve? _________________________________________________
BE YOUR BEST SELF !
6. For the following reaction, scientists are trying to form more hydrogen (H2). Using this reaction,
give the different ways that scientists can form more H2. Explain your answer. For at least one of
the ways, draw graphs to represent the initial conditions, disturbances, and final conditions. For
another of the ways, draw the nanoscopic version.
𝐻2 + 𝐵𝑟2 ↔ 2𝐻𝐵𝑟
Level: _________ What do you need to do differently to improve? _________________________________________________
7. If instead the above reaction looked like the one below, how would your answer to number five
change? Explain why you can make the revision and what would happen.
𝐻2 + 𝐵𝑟2 ↔ 2𝐻𝐵𝑟 + ℎ𝑒𝑎𝑡
Level: _________ What do you need to do differently to improve? _________________________________________________
BE YOUR BEST SELF !
8. For the following reaction, give as many methods as you can for scientists to form more NaCl.
Explain your answer. Draw graphs to represent the initial conditions, disturbance, and final
conditions for one method. For another, draw the nanoscopic version.
𝐵𝑎𝐶𝑙2 + 𝑁𝑎2 𝑆𝑂4 ↔ 2𝑁𝑎𝐶𝑙 + 𝐵𝑎𝑆𝑂4
Level: _________ What do you need to do differently to improve? _________________________________________________
Before the test
What about the test do you feel ready for?
What about the test are you still struggling with?
What will you do to prepare yourself between now and the test?
BE YOUR BEST SELF !
Answer Key
1. An answer key is attached so you can get immediate feedback as to what you know and what you
need to review more. An answer key allows you to check your work and focus more on the
problems you do not know. This means you can ask questions in class to make your studying
more productive.
A Level – Scholar
can explain the full
purpose of having
an answer key and
how to use the
answer key.
B Level – Scholar
can explain the
purpose of the
answer key but not
how to use it.
C Level – Scholar
can give examples of
how the answer key
is useful but not
explain the overall
purpose.
D Level – Scholar
can give key words
as to why the
answer key is
attached but not
explain the purpose.
F Level – Scholar
cannot explain why
the answer key is
attached or the
purpose of the
answer key.
2. Your brother is incorrect. Tell him that some reactions are reversible, meaning they can go
forward and backwards. In these cases, while reactants are being converted into products,
products are being converted into reactants.
A Level – Scholar
can explain why the
brother is incorrect
and correct the
brother completely.
B Level – Scholar
can explain why the
brother is incorrect
and can give part of
the correct
response.
C Level – Scholar
can explain why the
brother is incorrect
but cannot give the
correct response.
D Level – Scholar
can explain that the
brother is incorrect
but not why.
F Level – Scholar
cannot explain that
the brother is
incorrect.
3. Your sister is incorrect. Tell her that the rates of the forward and reverse reactions are equal at
equilibrium, the number of reactants stays constant, and the number of products stays constant.
However, the number of reactants does not necessarily equal the number of products.
A Level – Scholar
can explain why the
sister is incorrect
and correct the
sister completely.
B Level – Scholar
can explain why the
sister is incorrect
and can give part of
the correct
response.
C Level – Scholar
can explain why the
sister is incorrect
but cannot give the
correct response.
D Level – Scholar
can explain that the
sister is incorrect
but not why.
F Level – Scholar
cannot explain that
the sister is
incorrect.
4. Equilibrium occurs when the forward reaction rate is equal to the reverse reaction rate. In this
case, the concentrations of reactants and products are staying the same, though they are not
necessarily equal to each other.
A Level – Scholar
can define
equilibrium using
scientific vocabulary
and comparing rates
and concentrations.
B Level – Scholar
can define
equilibrium using
scientific vocabulary
but compares only
rates or
concentrations.
C Level – Scholar
can define
equilibrium but
does not use
scientific vocabulary
and/or mentions
but does not
compare rates
and/or
concentrations.
D Level – Scholar
can use key words
but does not form a
full definition for
equilibrium or
definition is slightly
wrong.
F Level – Scholar
cannot define
equilibrium.
5. Equilibrium is dynamic means that the reactants and products are constantly shifting. However,
the rates at which they are shifting are equal. The reactions are still occurring, but on a
macroscopic level, we cannot see that, so it looks like nothing is happening.
A Level – Scholar can
explain why
equilibrium is
dynamic, including a
rates comparison and
what the macroscopic
level looks like.
B Level – Scholar
can explain why
equilibrium is
dynamic but does
not explain the
macroscopic level.
C Level – Scholar
can explain why
equilibrium is
dynamic but does
not use scientific
vocabulary or
partially explains.
D Level – Scholar
can partially explain
why equilibrium is
dynamic without
scientific
vocabulary.
BE YOUR BEST SELF !
F Level – Scholar
cannot explain why
equilibrium is
dynamic.
6. To form more H2, scientists need to shift the reaction to the left, which will cause more reactants
to form. One way scientists can do this is by removing reactants, so remove H2 or Br2. Another
way is by adding more products, which means adding HBr. All of these (three ways) will shift
equilibrium to the left which will increase the amount of H2 formed.
A Level – Scholar
can explain the
necessary shift in
equilibrium and the
effects of that shift,
give the ways to
cause that shift, and
show that shift in
graphical and
nanoscopic form.
B Level – Scholar
can explain the
necessary shift in
equilibrium and
several ways to
cause the shift but
not all or creates
methods that do not
work. Scholar can
complete a full
graphical
representation at
least.
C Level – Scholar
can explain the
necessary shift in
equilibrium and one
way to cause that
shift. Scholar can
complete a full
graphical
representation.
D Level – Scholar
can explain explain
the necessary shift
in equilibrium but
not the effects or
give a way to cause
that shift but not
multiple. Scholar
can draw at least
one of the graphs.
F Level – Scholar
cannot explain the
necessary shift in
equilibrium and
cannot give a
correct way to cause
that shift.
7. Since heat is part of the equation now, scientists can increase the temperature, which is the same
thing as increasing the amount of heat. This will also shift the reaction to the left which will form
more H2, so this new equation has given us another way to form more H2.
A Level – Scholar
can explain the
revision to the
equation, the
revision to the
answer, and the
reasoning for the
new answer.
B Level – Scholar
can explain the
revision to the
equation and the
revision to the
answer but gives a
partial explanation
for the new method.
C Level – Scholar
can explain the
revision to the
equation and the
revision to the
answer but no
reason or an
incorrect reason.
D Level – Scholar
can explain the
revision to the
equation but no
revision to the
answer or an
incorrect one.
F Level – Scholar
cannot explain the
revision to the
equation.
8. NaCl is a product. To form more products, scientists must shift the reaction to the right. Scientists
can do this a number of ways. If they increase the amount of reactants (BaCl2 or Na2SO4),
equilibrium will shift right. Also, they could decrease the amount of products by removing NaCl or
BaSO4. Any of these four methods will produce more NaCl by shifting equilibrium to the right.
A Level – Scholar
can explain the
necessary shift in
equilibrium and the
effects of that shift,
give the ways to
cause that shift, and
show that shift in
graphical and
nanoscopic form.
B Level – Scholar
can explain the
necessary shift in
equilibrium and
several ways to
cause the shift but
not all or creates
methods that do not
work. Scholar can
complete a full
graphical
representation at
least.
C Level – Scholar
can explain the
necessary shift in
equilibrium and one
way to cause that
shift. Scholar can
complete a full
graphical
representation.
D Level – Scholar
can explain explain
the necessary shift
in equilibrium but
not the effects or
give a way to cause
that shift but not
multiple. Scholar
can draw at least
one of the graphs.
BE YOUR BEST SELF !
F Level – Scholar
cannot explain the
necessary shift in
equilibrium and
cannot give a
correct way to cause
that shift.