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Balancing Equations Practice Worksheet
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1. True or False:
C + O2 → CO2
In the chemical reaction above, the coefficient of oxygen is 2.
a. False
b. True
2. Which of the following equations is balanced?
a.
b.
c.
d.
H2 + O2 → H2 O
2H2 + O2 → 2H2 O
2H2 + O2 → H2 O
H2 + 2O2 → 2H2 O
3. True or False:
3Fe + 2O2 → Fe3O4
In the chemical reaction above, the coefficient and subscript of O2 are both 2.
a. True
b. False
4. Sam was given the following equation to balance: H2O → H2 + O2 . She balanced it as follows: 2HO → H2
+ O2 . Is this correct?
a. Yes
b. No
5. Which of the following chemical equations is balanced?
a. Zn + HCl → ZnCl2 + H2
b. Zn + 2HCl → ZnCl2 + H2
c. 2Zn + HCl → ZnCl2 + H2
d. 2Zn + 2HCl → ZnCl2 + H2
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6. Fill in the blank(s):
Fill in the blanks according to the chemical reaction below to indicate how many molecules of each
substance are present.
N2 + 3H2 → 2NH3
N2
Substance
Molecules Present
(Coefficient)
H2
NH3
____________________ ____________________ ____________________
7. Which of the following is the general form of a chemical equation?
a.
b.
c.
d.
Reactants Products
Products Reactants = 100%
Reactants
Products
Products
Reactants
8. Numbers called subscripts are used to balance chemical equations.
a. TRUE
b. FALSE
9. Which of the following equations is balanced?
a. CH4 + O2 → CO2 + H2O
b. CH4 + 2O2 → CO + 2H2O
c. CH4 + 2O2 → CO2 + 2H2O
d. CH4 + O2 → CO2 + 2H2O
10. A chemical _____ is a written method of representing the changes that occur in a chemical reaction.
Answer:
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Answer Keys
1. False
2.
2H2 + O2 → 2H2 O
3. True
4. No
5. Zn + 2HCl → ZnCl2 + H2
6. 1 , 3 , 2
7. Reactants
Products
8. FALSE
9. CH4 + 2O2 → CO2 + 2H2O
10. equation
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