2018
Name:____Jasleen Kindra_________________ Date: ______February 8 __________
Student Exploration: Balancing Chemical Equations
Select a font color other than black and type in your answers.
Submit your answers in Canvas.
Vocabulary: coefficient, combustion, compound, decomposition, double replacement, element,
molecule, product, reactant, single replacement, subscript, synthesis
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
The scouts are making s’mores out of toasted marshmallows, chocolate, and graham crackers.
1. What is wrong with the image below? ___The ingredients are not balanced __
2. Assuming a s’more requires two graham crackers, one marshmallow, and one piece of
chocolate, how many s’mores could you make with the ingredients shown? __2 s’mores__
Gizmo Warm-up
In a chemical reaction, reactants interact to form products.
This process is summarized by a chemical equation. In the
Balancing Chemical Equations Gizmo, look at the floating
molecules below the initial reaction: H2 + O2 H2O.
1. How many atoms are in a hydrogen molecule (H2)? _2__
2. How many atoms are in an oxygen molecule (O2)? __2__
3. How many hydrogen and oxygen atoms are in a water molecule (H2O)? __3 together___
4. In general, what does a subscript (such as the “2” in H2) tell you about the molecule?
________The subscript tells you how many atoms are in that molecule. _________
5. A chemical equation is balanced if the number of each type of atom on the left side is equal
to the number of each type on the right side. Is this reaction balanced? ___No.______
2018
Activity A:
Balancing
equations
Get the Gizmo ready:
Check that the Synthesis reaction is selected and
that all coefficients are set to one. (The
coefficients are the numbers in the boxes.)
Introduction: The equation H2 + O2 H2O is unbalanced because there are two oxygen atoms
on the reactants side of the equation, and only one on the products side of the equation. To
balance the equation, you cannot change the structure of any of the molecules, but you can
change the number of molecules that are used.
Question: How are chemical equations balanced?
1. Balance: Turn on Show histograms. The equation is balanced when there are equal
numbers of each type of atom represented on each side of the equation.
In the Gizmo, use the up and down arrows to adjust the numbers of hydrogen, oxygen, and
water molecules until the equation is balanced. When you are done, turn on Show
summary to check your answer.
Write the balanced equation here: __2___ H2 + __1___ O2 __2___ H2O
2. Solve: Turn off Show summary. Use the Choose reaction drop down menu to see other
equations, and balance them. Check your answers and then write the balanced equations.
____2_ Al + ___6__ HCl ___2__ AlCl3 + __3___ H2
___2__ NaCl __2___ Na + __1___ Cl2
___1__ Na2S + __2___ HCl ___2__ NaCl + _1____ H2S
___1__ CH4 + __2___ O2 __1___ CO2 + ___2__ H2O
3. Practice: Balance the following chemical equations. (These equations are not in the Gizmo.)
A. __2___ Na + __1___ Cl2 __2___ NaCl
B. __8___ Na + ___8__ H2O ___8__ NaOH + __4___ H2
C. ___2__ Mg + __1___ O2 ___2__ MgO
D. ___2__ KClO3 __2___ KCl + __3___ O2
E. __2___ Al + ___3__ CuO ___1__ Al2O3 + ___3__ Cu
F. ___1__ I2 + ___2__ Na2S2O3 ___2__ NaI + __1___ Na2S4O6
G. __6___ Mg + ___1__ P4 __2___ Mg3P2
2018
Activity B:
Classifying
reactions
Get the Gizmo ready:
Turn off Show summary and Show histograms.
Introduction: Chemical equations show how compounds and elements react with one
another. An element is a substance consisting of one kind of atom, such as aluminum (Al) or
oxygen gas (O2). A compound is a substance made of more than one kind of atom, such as
water (H2O) or table salt (NaCl).
Question: How are chemical reactions classified?
1. Match: Most chemical reactions can be classified as one of four types. Using the chemical
equations in the Gizmo as a guide, match the following definitions to the type of reaction.
__A__ One reactant is broken down into two
or more products.
__E__ A fuel is combined with oxygen to
produce carbon dioxide and water.
__C__ Two or more reactants combine to
form one product.
__D__ Two compounds react to form two
different compounds.
__B__ A compound reacts with an element to
form a new compound and a different
element.
A. Synthesis
B. Decomposition
C. Single replacement
D. Double replacement
E. Combustion
2. Practice: Balance each of the chemical equations below. (Some equations may already be
in balance.) In the space to the right, classify the reaction as a synthesis, decomposition,
single replacement, or double replacement reaction.
A. _1__ AgNO3 + _1_ KCl __1_ AgCl + _1__ KNO3___D___
B. _1__ H2O + __1_ SO3 __1_ H2SO4 ______ A_______
C. _2_ KI + _1__ Cl2 _2__ KCl + _1__ I2_______C______
D. _2__ NaHCO3 _1__ Na2CO3 + _1__ H2O + _1__ CO2____B_______
E. __1_ Zn + _2__ HCl __1_ ZnCl2 + _1__ H2 _________C____________
F. __1_ BaCl2 + _1__ Na2SO4 _1__ BaSO4 + _2__ NaCl ______D________
G. __1_ C3H8 + _5__ O2 _3__ CO2 + _4__ H2O ___E___________
H. __2_ Al + _3__ CuCl2 _2__ AlCl3 + __3_ Cu __________C____________
QUIZ RESULTS 80 PERCENT
ASSESSMENT
QUESTIONS:
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JASLEEN
KINDRA
Qi
a2 a3
04
Q5
SCORE
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Period
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Questions
&
Answers
1.
What
coefficients
would
balance the
following
equation?
—Al+_
Oy
+
Als
A.
2Al
+
302
=>
14205
B.
2Al
+
302
+
2Al.03
C.
3Al
+
303
+
2Al03
D.
4Al
+ 305
—
2Al03
Correct
Answer:
D.
44]
+
302
—+
241.05
Explanation:
In
answer
D,
both
sides
of
the
equation
contain
4
atoms
of
aluminum
(Al)
and
6
atoms
of
oxygen
(0).
In
answer
A,
there
are
6
atoms
of
oxygen
on
the
left
side of
the
equation
and
only
3
on
the
right side.
In
answer
B,
there
are
2
atoms
of
aluminum
on
the
left
side
and
4
on
the
right side.
In
answer
C
there
are
3
atoms
of
aluminum
on
the
left
side
and
4
on
the
right side.
Results
Summary
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Public
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or
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2018
