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Suppose 10 atoms of carbon (C) react with 20 atoms of oxygen (O) to form 10 molecules of carbon dioxide ( CO2 ). According to the law of conservation of matter, how many atoms are present in this reaction?(1 point) Responses 20 20 10 10 30 30 15 15

7 answers

To determine the total number of atoms present in the reaction according to the law of conservation of matter, we can analyze the given information.

In the reaction, we have:

  • 10 atoms of carbon (C)
  • 20 atoms of oxygen (O)

The products of the reaction are:

  • 10 molecules of carbon dioxide (CO₂)

Each molecule of CO₂ contains 1 carbon atom and 2 oxygen atoms. Therefore, the total number of atoms in the products is:

  • For 10 CO₂ molecules:
    • Carbon atoms: 10 (1 per CO₂ x 10 CO₂)
    • Oxygen atoms: 20 (2 per CO₂ x 10 CO₂)

Now, let's add up the number of atoms:

  • Total atoms on the reactants side:

    • 10 (C) + 20 (O) = 30 atoms

  • Total atoms on the products side:

    • 10 (C) + 20 (O) = 30 atoms

Since the number of atoms is the same on both sides of the reaction and is consistent with the law of conservation of matter, the total number of atoms present in this reaction is 30.

So the answer is 30.

Which procedure could be used to demonstrate that matter is conserved during a chemical change or reaction?(1 point) Responses Find the mass of an acid and a base. Combine them to produce water and a salt. Find the mass of the water and salt. Find the mass of an acid and a base. Combine them to produce water and a salt. Find the mass of the water and salt. Find the mass of a piece of paper. Tear the paper into smaller pieces. Find the mass of the pieces. Find the mass of a piece of paper. Tear the paper into smaller pieces. Find the mass of the pieces. Find the mass of a stick of butter. Heat the butter until it melts. Find the mass of the melted butter. Find the mass of a stick of butter. Heat the butter until it melts. Find the mass of the melted butter. Find the mass of a log. Burn the log until it turns to ash and smoke. Find the mass of the ash. Find the mass of a log. Burn the log until it turns to ash and smoke. Find the mass of the ash.

To demonstrate that matter is conserved during a chemical change or reaction, the best procedure would be:

Find the mass of an acid and a base. Combine them to produce water and a salt. Find the mass of the water and salt.

This procedure clearly illustrates a chemical reaction where two substances (acid and base) react to form new products (water and salt). By measuring the mass of the reactants before the reaction and the mass of the products after the reaction, you can show that the total mass remains constant, thus demonstrating the law of conservation of matter.

In contrast, the other options involve physical changes (tearing paper, melting butter) or incomplete measurements (burning a log, which results in gases released into the atmosphere), which do not effectively demonstrate the conservation of mass in a chemical reaction.

Whjavascript:void(0)at is always true according to the Law of Conservation of Matter?(1 point) Responses New molecules cannot be formed from the reactants during a chemical reaction. New molecules cannot be formed from the reactants during a chemical reaction. The total number of molecules before and after a chemical reaction stays the same. The total number of molecules before and after a chemical reaction stays the same. Atoms created during a chemical reaction must have the same mass as the atoms in the reactants. Atoms created during a chemical reaction must have the same mass as the atoms in the reactants. Atoms can be rearranged during a chemical reaction but cannot be added or taken away.

The statement that is always true according to the Law of Conservation of Matter is:

Atoms can be rearranged during a chemical reaction but cannot be added or taken away.

This reflects the fundamental principle of the law, which states that matter is not created or destroyed in a chemical reaction. Instead, the same atoms present in the reactants are simply rearranged to form products. The total mass of the reactants before the reaction will equal the total mass of the products after the reaction.

The other options contain inaccuracies:

  • New molecules can be formed from reactants during a chemical reaction (which is actually a key part of what happens).
  • The total number of molecules does not have to stay the same; it can change as molecules combine to form new substances.
  • Atoms themselves are not created during a chemical reaction; they are rearranged.
A student combines two liquids in a beaker. She observes that the mass of the combined liquid is less than the mass of the two separate liquids. The student claims that this observation shows that matter is not conserved in chemical reactions. Which statement explains why the student’s claim is incorrect?(1 point) Responses The product contained fewer atoms than the reactants. The product contained fewer atoms than the reactants. The reaction produced a gas that escaped the beaker. The reaction produced a gas that escaped the beaker. The reaction did not change the physical properties of the liquids. The reaction did not change the physical properties of the liquids. The combined liquid was warmer than the two separate liquids. The combined liquid was warmer than the two separate liquids.

The correct response to explain why the student’s claim is incorrect is:

The reaction produced a gas that escaped the beaker.

This explanation accounts for the observed decrease in mass. If a gas is released into the air during the mixing of the two liquids, the mass of the combined system will be less than the mass of the individual liquids before they were combined. This situation does not violate the Law of Conservation of Matter; rather, it indicates that some of the matter (in the form of gas) has left the system, leading to a lower measured mass.

The other options do not accurately explain the situation regarding the conservation of matter:

  • Saying the product contained fewer atoms than the reactants isn’t correct for reactions; atoms are rearranged, not lost in closed systems.
  • Changes in physical properties or temperature alone do not affect mass in this context.