Conservation of Mass in Reactions

Which of the following best describes the Law of Conservation of Mass in a chemical reaction?

• Mass is lost during a chemical reaction.

• Mass is gained during a chemical reaction.

• Mass is neither created nor destroyed during a chemical reaction.

• Mass is converted into energy during a chemical reaction.

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TEKS.SCI.8.6E

• 6

• 12

• 18

• 24

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TEKS.SCI.8.6E

Explain how the rearrangement of atoms in a chemical reaction supports the Law of Conservation of Mass.

• Atoms are destroyed and recreated in a chemical reaction.

• Atoms are rearranged into different molecules, conserving mass.

• Atoms are converted into energy, conserving mass.

• Atoms are lost to the surroundings, conserving mass.

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TEKS.SCI.8.6E

Which of the following is a simple procedure to demonstrate the conservation of mass in a closed system?

• Mixing vinegar and baking soda in an open container.

• Burning a piece of paper in an open flame.

• Dissolving salt in water in a sealed bag.

• Melting ice in an open bowl.

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TEKS.SCI.8.6E

During photosynthesis, which molecules are rearranged to form glucose and oxygen?

• Water and nitrogen

• Carbon dioxide and water

• Oxygen and glucose

• Carbon dioxide and nitrogen

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TEKS.SCI.8.6E

A student claims that mass is not conserved in a chemical reaction because the mass of the products is less than the mass of the reactants. How would you evaluate this claim?

• The student is correct; mass is often lost as energy.

• The student is incorrect; mass is always conserved in a closed system.

• The student is correct; mass can be converted to energy.

• The student is incorrect; mass is only conserved in open systems.

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TEKS.SCI.8.6E

What is the role of chemical equations in demonstrating the conservation of mass?

• They show the energy changes in a reaction.

• They illustrate the rearrangement of atoms.

• They indicate the speed of a reaction.

• They predict the color change in a reaction.

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TEKS.SCI.8.6E

• The number of hydrogen atoms decreases.

• The number of oxygen atoms increases.

• The number of each type of atom remains the same.

• The number of hydrogen atoms increases.

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TEKS.SCI.8.6E

Design an experiment to show that mass is conserved in a chemical reaction using household materials.

• Burn a candle and measure the mass of the wax.

• Mix baking soda and vinegar in a sealed container and measure the mass before and after.

• Dissolve sugar in water and measure the mass of the sugar.

• Heat water and measure the mass of the steam.

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TEKS.SCI.8.6E

Which of the following statements is true about the conservation of mass in photosynthesis?

• Mass is lost as energy during photosynthesis.

• Mass is gained from sunlight during photosynthesis.

• Mass is conserved as atoms are rearranged into new molecules.

• Mass is destroyed during photosynthesis.

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TEKS.SCI.8.6E