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Counting Atoms in Chemical Formulas

A Grade 12 chemistry worksheet focusing on counting atoms in various chemical formulas, including those with polyatomic ions and hydrates.

Grade 12 Science ChemistryCounting Atoms
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Standards

HS-PS1-7
7 sections · Free to use · Printable
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Counting Atoms in Chemical Formulas

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Date:

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Carefully read each chemical formula and determine the total number of atoms for each element present. Show your work where indicated.

1. In the compound H₂O, there are   hydrogen atoms and   oxygen atoms.

2. How many atoms of each element are in C₆H₁₂O₆ (glucose)?

Carbon:  

Hydrogen:  

Oxygen:  

3. Explain how to count atoms in a formula containing parentheses, such as Ca(NO₃)₂. Provide the total count for each element in this compound.

4. What is the total number of oxygen atoms in 3 molecules of sulfuric acid, 3H₂SO₄?

a

4

b

7

c

12

d

16

5. Consider the compound Copper(II) sulfate pentahydrate, CuSO₄·5H₂O. Determine the total number of atoms for each element in this hydrate.

Show your detailed calculations for each element.

6. The coefficient in front of a chemical formula multiplies the number of all atoms in that formula.

T

True

F

False