Conservation of Mass in Reactions

During a lively chemistry class, Scarlett and Benjamin are debating: 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 created during a chemical reaction.

• Mass is conserved and remains constant during a chemical reaction.

• Mass is destroyed during a chemical reaction.

Answer explanation

The Law of Conservation of Mass states that in a chemical reaction, mass is neither created nor destroyed. Therefore, the correct choice is that mass is conserved and remains constant during a chemical reaction.

Tags

TEKS.SCI.8.6E

• 6

• 12

• 18

• 24

Answer explanation

In the equation, there are 6 O2 molecules produced, contributing 12 oxygen atoms, and 6 CO2 molecules react, contributing 6 oxygen atoms. Thus, 12 + 6 = 18 oxygen atoms are present on both sides, making the correct answer 18.

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TEKS.SCI.8.6E

Hey science explorers! Aria and Liam are in a lab, and they need your help. Which of the following statements is true about the magical dance of atoms in a chemical reaction?

• Atoms are destroyed and new atoms are created.

• Atoms are rearranged to form new substances.

• Atoms are unchanged and remain in their original form.

• Atoms are lost during the reaction.

Answer explanation

In a chemical reaction, atoms are not created or destroyed; they are rearranged to form new substances. This means the correct statement is that atoms are rearranged to form new substances.

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TEKS.SCI.8.6E

Hey science explorers! During photosynthesis, which of the following statements about mass conservation would impress Liam, Elijah, and Lily the most?

• The mass of the reactants is greater than the mass of the products.

• The mass of the products is greater than the mass of the reactants.

• The mass of the reactants equals the mass of the products.

• The mass of the reactants is less than the mass of the products.

Answer explanation

In photosynthesis, the law of mass conservation states that the mass of the reactants (carbon dioxide and water) equals the mass of the products (glucose and oxygen), confirming that matter is neither created nor destroyed.

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TEKS.SCI.8.6E

During a magical chemistry class, Luna and Mason are mixing potions. If the total mass of their magical ingredients is 50 grams, what should be the total mass of the resulting potion according to the Law of Conservation of Mass?

• 25 grams

• 50 grams

• 75 grams

• 100 grams

Answer explanation

According to the Law of Conservation of Mass, the total mass of the products must equal the total mass of the reactants. Since the reactants weigh 50 grams, the products must also weigh 50 grams.

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TEKS.SCI.8.6E

During a fun science experiment, Anika and Arjun are exploring mass conservation. Which of the following scenarios best illustrates this principle?

• Burning wood and losing mass as ash.

• Dissolving sugar in water and the mass of the solution equals the mass of sugar plus water.

• Melting ice and losing mass as water.

• Evaporating water and losing mass as vapor.

Answer explanation

Dissolving sugar in water demonstrates mass conservation, as the total mass of the solution equals the combined mass of the sugar and water, showing that mass is neither created nor destroyed in the process.

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TEKS.SCI.8.6E

• 2 before, 2 after

• 4 before, 4 after

• 4 before, 2 after

• 2 before, 4 after

Answer explanation

In the reaction, there are 2 molecules of H2, each containing 2 hydrogen atoms, totaling 4 hydrogen atoms before the reaction. After the reaction, 2 water molecules (H2O) contain 4 hydrogen atoms, so there are also 4 hydrogen atoms after.

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TEKS.SCI.8.6E

Imagine you're a detective like Liam or Abigail, solving the mystery of why mass is conserved in chemical reactions. What's the primary reason behind this scientific enigma?

• Atoms are created during the reaction.

• Atoms are rearranged but not created or destroyed.

• Atoms are destroyed during the reaction.

• Atoms are converted into energy.

Answer explanation

The primary reason mass is conserved in chemical reactions is that atoms are rearranged but not created or destroyed. This means the total mass remains constant throughout the reaction.

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TEKS.SCI.8.6E

During a magical chemistry class, Kai and Avery are observing a chemical reaction. According to the Law of Conservation of Mass, what happens to the total number of atoms?

• The total number of atoms increases.

• The total number of atoms decreases.

• The total number of atoms remains the same.

• The total number of atoms is unpredictable.

Answer explanation

According to the Law of Conservation of Mass, matter cannot be created or destroyed in a chemical reaction. Therefore, the total number of atoms remains the same before and after the reaction.

Tags

NGSS.MS-PS1-5

• 2

• 4

• 6

• 8

Answer explanation

In the reaction, there are 2 O2 molecules on the left side, contributing 4 oxygen atoms. On the right side, CO2 has 2 oxygen atoms, and 2H2O has 2 more, totaling 4. Thus, both sides have 6 oxygen atoms.

Tags

NGSS.MS-PS1-5