Conservation of Mass and Percent Composition

A chemical reaction occurs where 20 grams of sodium react with 30 grams of chlorine to form sodium chloride. What is the total mass of sodium chloride produced?

• 50 grams

• 40 grams

• 30 grams

• 60 grams

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DOK Level 2: Skill/Concept

In a reaction, 50 grams of iron react with sulfur to form 80 grams of iron sulfide. How much sulfur was used in the reaction?

• 30 grams

• 50 grams

• 80 grams

• 20 grams

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DOK Level 2: Skill/Concept

A 75.0 gram sample of a compound contains 15.0 grams of carbon. What is the mass percent of carbon in the compound?

• 20.0%

• 25.0%

• 30.0%

• 15.0%

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DOK Level 2: Skill/Concept

A 200.0 gram sample of a compound contains 50.0 grams of oxygen. What is the mass percent of oxygen in the compound?

• 20.0%

• 25.0%

• 30.0%

• 40.0%

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DOK Level 2: Skill/Concept

Compound XY is made of 27 grams of element X and 54 grams of compound Y. What is the mass percent of compound X?

• 27.8%

• 33.3%

• 50.0%

• 20.0%

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DOK Level 2: Skill/Concept

In the picture, which box on the right shows the correct products according to the Law of Conservation of Mass?

• A

• B

• C

• D

Tags

NGSS.MS-PS1-5

Is mass being conserved?

• Yes

• No

• Not enough information

Tags

NGSS.MS-PS1-5

In chemical reactions, what does the principle of conservation of mass mean?

• Matter is not created or destroyed.
• The total mass of the reactants is greater than the total mass of the products.
• The total mass of the reactants is less than the total mass of the products.
• Matter is not changed.
  

Tags

NGSS.MS-PS1-5