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Worksheets

Balancing Chemical Equations

Total questions: 10

Worksheet time: 3hrs 30mins

Name
Class
Date
1.

How many Hydrogen atoms are in 4H2O?

a)

6

b)

8

c)

2

d)

4

2.

How many Magnesium atoms are in 10MgCl2?

a)

10

b)

5

c)

20

d)

12

3.

How many Nitrogen atoms are in (NH₄)₂CrO₄?

a)

1

b)

2

c)

8

d)

6

4.

How many Hydrogen atoms in 3(NH₄)₂CrO₄?

a)

4

b)

2

c)

8

d)

24

e)

9

5.

A subscript is the small number below the element symbol that tells the number of _______ of that element.

a)

atoms

b)

valence electrons

c)

protons

d)

elements

6.

Balance this equation:

H2 + Cl2 ---> HCl

a)

It is balanced.

b)

H2 + Cl2 ---> 2HCl

c)

3H2 + Cl2 ---> 6HCl

d)

H2 + 3Cl2 ---> 6HCl

7.

Balance this equation:

HgO ---> Hg + O2

a)

It is balanced.

b)

2HgO ---> 2Hg + O2

c)

2HgO ---> Hg + O2

d)

HgO ---> Hg + 2O2

8.
How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl2 + H2
a)
1
b)
2
c)
3
d)
4
9.
Balance this equation:
P4+O2  -->  P2O3
a)
3 P4+ O2 --> 2 P2O3
b)
 P4+ O2 --> 2 P2O3
c)
 P4+ 3 O2 --> 2 P2O3
d)

 P4 + O2 --> P4O2

10.

Which of the following is balanced?

a)

Mg + HCl --> H2 + MgCl2

b)

H2O + CO2 --> H2CO3

c)

KClO3 --> KCl + O2

d)

H2 + O2 --> H2O