Law of Conservation of Mass Review

What is the law of conservation of mass?

• Mass can be created and destroyed.

• Mass is neither created nor destroyed in a closed system.

• Mass is always increasing in a chemical reaction.

• Mass is always decreasing in a chemical reaction.

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NGSS.MS-PS1-5

Which of the following best describes a closed system in the context of the conservation of mass?

• A system where energy can enter or leave, but mass cannot.

• A system where both mass and energy can enter or leave.

• A system where mass can enter or leave, but energy cannot.

• A system where neither mass nor energy can enter or leave.

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NGSS.MS-PS1-5

In a chemical reaction, if the mass of the reactants is 50 grams, what should be the mass of the products according to the law of conservation of mass?

• 25 grams

• 50 grams

• 75 grams

• 100 grams

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NGSS.MS-PS1-5

Which of the following is an example of the law of conservation of mass in a real-world scenario?

• A car accelerating on a highway.

• A tree growing in a forest.

• Water boiling in a pot with a lid on.

• A balloon popping in the air.

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

• 18 grams

• 36 grams

• 34 grams

• 36 grams

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

Why is the law of conservation of mass important in balancing chemical equations?

• It ensures that the equations are aesthetically pleasing.

• It ensures that the number of atoms for each element is the same on both sides of the equation.

• It ensures that the reaction will occur faster.

• It ensures that the products are always more than the reactants.

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which of the following statements is true about mass in a closed system?

• Mass can increase if energy is added.

• Mass can decrease if energy is removed.

• Mass remains constant regardless of energy changes.

• Mass can fluctuate based on temperature changes.

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NGSS.MS-PS1-5

A sealed container has a chemical reaction occurring inside. If the mass of the container and its contents before the reaction is 100 grams, what will be the mass after the reaction?

• 90 grams

• 100 grams

• 110 grams

• 120 grams

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

How does the law of conservation of mass apply to the process of photosynthesis in plants?

• Plants create new mass from sunlight.

• Plants convert mass into energy.

• The mass of carbon dioxide and water is converted into the mass of glucose and oxygen.

• The mass of glucose is destroyed to release energy.

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NGSS.MS-PS1-5

NGSS.MS-LS1-6

In a laboratory experiment, a student combines 10 grams of substance A with 15 grams of substance B in a closed container. After the reaction, the mass of the container and its contents is measured. What should the mass be?

• 20 grams

• 25 grams

• 30 grams

• 35 grams

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NGSS.MS-PS1-5

NGSS.MS-PS1-2