Free Printable LOCOM Counting Atoms

1.

How many Hydrogen are in 4 H₂O?

a)

6

b)

8

c)

2

d)

4

2.

How many Magnesium are in 10 MgCl₂?

a)

10

b)

5

c)

20

3.

What is the product?

2 H₂ + O₂ → 2 H₂O

a)

------>

b)

2H₂O

c)

2H₂+ O₂

4.

How many atoms of Carbon are in the compound C₂H₈O ?

a)

8

b)

2

c)

1

d)

11

5.

Why is the following chemical equation not balanced?
H_{2 +}O₂→ H₂O

a)

each side of the equation has a different number of oxygen atoms

b)

each side of the equation has a different number of hydrogen atoms

c)

each side has the same mass

6.

Is the following equation balanced or unbalanced?
Fe + S → FeS

a)

balanced

b)

unbalanced

7.

What is the part of the chemical equation in green (left side) called?
Fe + S → FeS

a)

products

b)

reactants

c)

yield

d)

chemical formula

8.

How many Sodium atoms are in 6 NaCl?

a)

1

b)

12

c)

6

9.

Which equation follows the Law of Conservation of Matter?

a)

H₂ + O₂ ------> H₂O

b)

C + 2H₂ ----> CH₄

c)

2Fe₂O₃ ------> 2O₂ + 4Fe

10.

How many atoms of aluminum are on each side of the following equation:

4 Al + 3 O₂→ 2 Al₂O₃

a)

2

b)

6

c)

1

d)

4

11.

How many Oxygen atoms are in H₂O?

a)

1

b)

2

c)

0

d)

4

12.

How many Potassium atoms are in the chemical formula below?

P₄O₁₀

a)

4

b)

10

c)

14

d)

Potassium is not in this chemical formula

13.

How many Nitrogen atoms are in the in H₂C₃O₄N₅?

a)

2

b)

3

c)

14

d)

5

14.

How many different elements are present in this compound? (Careful!)

Mg₂As₃COHNi₂

a)

2

b)

4

c)

6

d)

10

15.

5 N₂O represents the laughing gas you might have at the dentist.

How many atoms of oxygen are present here?

a)

10

b)

2

c)

7

d)

5

16.

The red (big) numbers in the image below represent ________

a)

subscripts

b)

coefficients

c)

I don't know, and don't want to try

d)

None of the answers are correct

17.

How many Hydrogen atoms are in 4H₂O?

a)

6

b)

8

c)

2

d)

4

18.

How many total Potassium atoms are in this formula?

a)

8

b)

2

c)

4

d)

12

19.

How many total atoms are in this chemical formula: NaC₂H₃O₂

a)

6

b)

8

c)

4

d)

9

20.

Which chemical formula has 21 atoms.

a)

C₉H₈O₄

b)

H₂SO₄

c)

CH₃COCH₃

d)

H₂SO₃

21.

Which of the following represent chemical equations? Check all that apply.

a)

$2Na\ +\ H_2O\ \rightarrow\ 2NaOH\ +\ H_2$

b)

$2KClO_3\ \ \rightarrow\ 2KCl\ +\ 3O_2$

c)

$2Fe\ +\ 3O_{2\ }\rightarrow\ 2Fe_2O_3$

d)

$2H_2O$

e)

$3O_3\ ,\ H_2O$

22.

The formula shown here represents the breakdown of a metal into rust.

What elements are involved in this reaction?

Check all that apply.

$4Fe\ +\ 3O_2\ \rightarrow\ 2Fe_2O_3$

a)

Iron

b)

Oxygen

c)

Carbon

d)

Nitrogen

23.

6 CO₂+ 6 H₂O → C₆H₁₂O₆ + 6 O₂

a)

Balanced

b)

Unbalanced

24.

2 AgI + Na₂S → Ag₂S + 2 NaI

a)

Balanced

b)

Unbalanced

25.

4AgI + Na₂S → AgS + 3NaI

a)

Balanced

b)

Not Balanced

LOCOM Counting Atoms

Total questions: 25

Worksheet time: 34mins

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