This material equips the learners on how balancing chemical equation works. This shows the systematic process on how this is done.

1. z
Balancing
Chemical
Equations
Prepared by: RAJEEV G. BAYAN
SCIENCE Grade 10
Fourth Quarter

2. z
OVERVIEW
Can you still remember how we produce Ammonia
gas, NH3, from N2 and O2?
What does its Chemical Equation look?
SPLENDID! You really learned a
lot from yesterday.
It is
N2 + 3 H2 → 2 NH3

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OVERVIEW
For the product : 2 NH3
What number represents the coefficient? 2
What number represents the subscript?
3
What element is represented by letter H? Hydrogen
How many atoms of H are there? 6
What element is represented with letter N? Nitrogen
How many atoms of N are there? 2

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OVERVIEW
Why do you think there is a need to write the
coefficient(s) in the Chemical Equation?
That’s
right!
So that the Chemical Equation is balanced.
… and this is today’s lesson.
Balancing Chemical Equations

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PRE-ASSESSMENT
The image below is what we call the
Pharaoh’s Serpent”. The Chemical
Equation is shown below:
__?___Hg(SCN)2 → 2 HgS + CS2 + C3N.
What should be the Coefficient written
before Mercury (II) thiocyanate?
Answer: 2

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PRE-ASSESSMENT
The complete Chemical Reaction of an
exploding Gummy Bear is:
C6H12O6 + 4KClO3 -> 6CO2 + 6H20 + _?_KCl
What should be the Coefficient written
before Potassium chloride?
Answer: 4

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How did you get the answer correctly?
TREMENDOUS!
You got it right.
1. You just simply count the number of atoms of each
elements in the reactant side and on the product side.
2. Since you have noticed that the Chemical Equation is not
balanced, you added a COEFFICIENT before the Chemical
Formula.
EASY RIGHT?

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Let’s do it systematically!
Suppose are given is Al + CuCl2 → AlCl3 + Cu
How do we balance this?
1 – Write the unbalanced chemical
equation, make sure you have
followed correctly the rules in
writing formula of compounds.
Al + CuCl2 → AlCl3 + Cu
2 – Take note of the elements
present in the reactant and product
sides.
REACTANT
Al
Cl
Cu
PRODUCT
Al
Cl
Cu
3 – Count the number of atom/s of
each element present on the
reactant and product side.
REACTANT
Al = 1
Cl = 2
Cu = 1
PRODUCT
Al = 1
Cl = 3
Cu = 1

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Let’s do it systematically!
Given: Al + CuCl2 → AlCl3 + Cu
4 – As in the number of atoms,
chlorine is unbalanced for both the
reactant side and the product side.
We’ll focus for Cl in this case.
5 – Add coefficients that could make
chlorine equal for both sides.
6 – Let’s recount the number of
atoms. Since We have noticed that
both Al and Cu are unbalanced.
REACTANT
Al = 1
Cl = 2
Cu = 1
PRODUCT
Al = 2
Cl = 6
Cu = 1
Al + 3CuCl2 → 2AlCl3 + Cu
REACTANT
Al = 1
Cl = 6
Cu = 3
PRODUCT
Al =
Cl = 3
Cu = 1

10. z
Let’s do it systematically!
Given: Al + CuCl2 → AlCl3 + Cu
7 – Write the coefficients that
could balance both Al and Cu.
8 – Let’s recount the number of
atoms. Since We have noticed that
all atoms of the elements in both
sides are equal.
PRODUCT
Al = 2
Cl = 6
Cu = 3
2Al + 3CuCl2 → 2AlCl3 + 3Cu
REACTANT
Al = 2
Cl = 6
Cu = 3
9 – Write the Balanced Chemical
Equation.
2Al + 3CuCl2 → 2AlCl3 + 3Cu

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Let’s have another!
Suppose are given is H2SO4 + NaOH→ Na2SO4 + H2O
How do we balance this?
1 – Write the unbalanced chemical
equation, make sure you have
followed correctly the rules in
writing formula of compounds.
H2SO4 + NaOH→ Na2SO4 + H2O
2 – Take note of the elements
present in the reactant and product
sides.
REACTANT
H
S
O
Na
PRODUCT
H
S
O
Na
3 – Count the number of atom/s of
each element present on the
reactant and product side.
REACTANT
H=3
S=1
O=5
Na=1
PRODUCT
H=2
S=1
O=5
Na=2

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Let’s do it systematically!
Given: H2SO4 + NaOH→ Na2SO4 + H2O
4 – As in the number of atoms,
Hydrogen and Sodium are
unbalanced for both the reactant
side and the product side. We’ll
focus for Na first in this case.
5 – Add coefficients that could make
chlorine equal for both sides.
6 – Let’s recount the number of
atoms. Since We have noticed that
both H and O are unbalanced.
REACTANT
H=3
S=1
O=5
Na=1
PRODUCT
H=2
S=1
O=5
Na=2
H2SO4 + 2NaOH→ Na2SO4 + H2O
REACTANT
H=4
S=1
O= 6
Na=2
PRODUCT
H=2
S=1
O=5
Na=2

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Let’s do it systematically!
Given: H2SO4 + NaOH→ Na2SO4 + H2O
7 – Write the coefficients that
could balance both H and O.
8 – Let’s recount the number of
atoms. Since We have noticed that
all atoms of the elements in both
sides are equal.
9 – Write the Balanced Chemical
Equation.
H2SO4 + 2NaOH→ Na2SO4 + 2H2O
H2SO4 + 2NaOH→ Na2SO4 + 2H2O
REACTANT
H=4
S=1
O= 6
Na=2
PRODUCT
H=4
S=1
O=6
Na=2

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QUIZ Galore!
Balance the following Chemical Equations:
▪ 𝐙𝐧 + 𝐇𝐂𝐥 → 𝒁𝒏𝑪𝒍𝟐 + 𝑯𝟐
▪ 𝑪𝑯𝟒 + 𝑶𝟐 → 𝑪𝑶𝟐 + 𝑯𝟐𝐎
▪ 𝑺𝒊𝑪𝒍𝟒 + 𝑯𝟐𝐎 → 𝑺𝒊𝑶𝟐 + 𝐇𝐂𝐥
▪ 𝑵𝟐 + 𝑶𝟐 + 𝑯𝟐𝐎 → 𝑯𝑵𝑶𝟑
▪ 𝑵𝒂𝑯𝑪𝑶𝟑 + 𝑯𝟐𝐒 → 𝑵𝒂𝟐𝐒 + 𝑪𝑶𝟐 + 𝑯𝟐𝐎

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QUIZ Answers:
Check your own work.
▪ 𝐙𝐧 + 𝟐𝐇𝐂𝐥 → 𝐙𝐧𝐂𝐥𝟐 + 𝐇𝟐
▪ 𝐂𝐇𝟒 + 𝟐𝐎𝟐 → 𝐂𝐎𝟐 + 𝟐𝐇𝟐𝐎
▪ 𝐒𝐢𝐂𝐥𝟒 + 𝟐𝐇𝟐𝐎 → 𝐒𝐢𝐎𝟐 + 𝟒𝐇𝐂𝐥
▪ 𝟐𝐍𝟐 + 𝟓𝐎𝟐 + 𝟐𝐇𝟐𝐎 → 𝟒𝐇𝐍𝐎𝟑
▪ 𝟐𝐍𝐚𝐇𝐂𝐎𝟑 + 𝐇𝟐𝐒 → 𝐍𝐚𝟐𝐒 + 𝟐𝐂𝐎𝟐 + 𝟐𝐇𝟐𝐎

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REFERENCES:
DepED Reference(s):
Teacher’s Guide: pp. 296 – 298
Learners’ Material: pp. 419 – 421
Other Reference(s):
Rabago, L., Lagunzad, C., et. al., K to 12 Science and Technology Laboratory Manual and Workbook,
Vibal Group Inc., 2014, Exercise 4.14, p. 90
Valdoz, M., Aquino, M., et. al., Science Links Worktext for Scientific and Technological Literacy Grade
10: Curriculum – aligned K to 12 Standard Based Assessment, Rex Bookstore Inc., 2015, pp. 392 –
394
Vengco, L., Navaza, D., You and the Natural World Science K to 12 Curriculum Compliant Grade 10,
Phoenix Publishing House Inc., 2015, p. 284