Percent Composition by Mass
This worksheet focuses on calculating percent composition by mass for various chemical compounds, suitable for Grade 10 Chemistry students.
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Percent Composition by Mass
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Read each question carefully and calculate the percent composition by mass for the given elements in each compound. Show all your work.
1. Calculate the percent composition by mass of Carbon (C) in methane (CH₄).
2. Determine the percent composition by mass of Oxygen (O) in water (H₂O).
3. The formula for calculating percent composition by mass is (mass of element / ) * 100%.
4. To find the mass of an element in a compound, you multiply its atomic mass by the number of of that element in the compound.
5. Which of the following compounds has the highest percent composition by mass of Nitrogen (N)?
NH₃
N₂O
NO₂
N₂H₄
6. A compound contains 32.38% sodium (Na), 22.02% sulfur (S), and 45.60% oxygen (O). What is the empirical formula of this compound?
Atomic Masses (g/mol): H=1.01, C=12.01, N=14.01, O=16.00, Na=22.99, S=32.07
