Counting Atoms in Chemical Formulas
A Grade 11 Chemistry worksheet to practice counting atoms in various chemical formulas, including those with parentheses and coefficients.
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Counting Atoms in Chemical Formulas
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Read each chemical formula carefully and determine the number of atoms for each element present. Show your work or explain your reasoning where indicated.
1. In H₂O, there are hydrogen atoms and oxygen atoms.
2. In CO₂, there is carbon atom and oxygen atoms.
3. In NaCl, there is sodium atom and chlorine atom.
4. In C₆H₁₂O₆, there are carbon atoms, hydrogen atoms, and oxygen atoms.
1. How many atoms of each element are in 2H₂SO₄?
2. Determine the number of atoms for each element in 3Ca(NO₃)₂.
1. How many total atoms are present in one molecule of Al₂(SO₄)₃?
8
12
17
19
2. In the formula 4Fe₂(Cr₂O₇)₃, how many oxygen atoms are present?
7
21
28
84
1. In Mg(OH)₂, there are two oxygen atoms and two hydrogen atoms.
True
False
2. The coefficient in front of a chemical formula multiplies all atoms in that formula.
True
False
1. A compound has the formula (NH₄)₃PO₄. If you have 5 molecules of this compound, how many atoms of each element (Nitrogen, Hydrogen, Phosphorus, Oxygen) are present in total? Show your calculations.