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Percent Composition by Mass Worksheet

A Grade 12 Chemistry worksheet focusing on calculating percent composition by mass for various compounds.

Grade 12 Science ChemistryPercent Composition by Mass
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Includes

2 Short AnswerFill in the BlanksMultiple ChoiceTrue / FalseText

Standards

HS-PS1-7

Topics

ChemistryPercent CompositionMassStoichiometry
8 sections · Free to use · Printable
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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 indicated elements. Show all your work and include appropriate units.

1. Calculate the percent composition by mass of carbon in C₁₂H₂₂O₁₁ (sucrose).

2. Determine the percent composition by mass of oxygen in H₂SO₄ (sulfuric acid).

3. The sum of the percent compositions of all elements in a compound should ideally add up to   percent.

4. To find the percent composition by mass, you divide the mass of the   in the compound by the total   mass of the compound, then multiply by 100.

5. Which of the following compounds has the highest percentage of nitrogen by mass?

a

NO₂

b

N₂O

c

NH₃

d

N₂O₅

6. The empirical formula of a compound is always the same as its molecular formula.

T

True

F

False

7. A sample of a compound is found to contain 5.60 g of nitrogen and 16.0 g of oxygen. What is the empirical formula of this compound?

8. Imagine you are in a lab preparing a solution. What piece of glassware is commonly used for precise volume measurements, as shown in the image to the right?

beaker