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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 15 15 30 30 10 10 20

11 answers

According to the law of conservation of matter, the total number of atoms in the reactants must equal the total number of atoms in the products.

In this reaction:

  • Reactants:

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

    Total in reactants = 10 (C) + 20 (O) = 30 atoms

  • Products:

    • 10 molecules of carbon dioxide (CO₂), which contains 1 carbon atom and 2 oxygen atoms per molecule.
    • Thus, for 10 CO₂:
      • Carbon atoms = 10 (1 atom per molecule × 10 molecules)
      • Oxygen atoms = 20 (2 atoms per molecule × 10 molecules)

    Total in products = 10 (C) + 20 (O) = 30 atoms

Since both the reactants and products contain a total of 30 atoms, the correct response 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.

To demonstrate that matter is conserved during a chemical change or reaction, the procedure should involve a chemical reaction where the total mass of the reactants is compared to the total mass of the products.

The appropriate procedure from the provided options is:

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 allows you to measure the mass of the reactants (the acid and base) before the reaction and compare it to the combined mass of the products (water and salt) after the reaction. If the mass remains the same, it demonstrates that matter is conserved during the chemical reaction.

What is always true according to the Law of Conservation of Matter?(1 point) Responses 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. New molecules cannot be formed from the reactants during a chemical reaction. New molecules cannot be formed from the reactants during a chemical reaction. 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 law states that in a chemical reaction, the total number of atoms remains constant; they are merely rearranged to form new substances. Therefore, while the number of atoms is conserved, the specific arrangements of those atoms (and the molecules they form) can change.

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 combined liquid was warmer than the two separate liquids. The combined liquid was warmer than the two separate liquids. The reaction did not change the physical properties of the liquids. The reaction did not change the physical properties of the liquids. 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 statement that explains why the student’s claim is incorrect is:

The reaction produced a gas that escaped the beaker.

If gas was produced during the reaction and it escaped the beaker, this would account for the observed decrease in mass. The Law of Conservation of Matter states that matter cannot be created or destroyed; therefore, if there was a loss of mass, it is likely due to the escape of gas rather than a violation of the law.

In which chemical equation is the number of atoms in the reactants the same as the number of atoms in the products?(1 point) Responses CH4 + O2 → CO2 + 2H2O CH 4 + O 2 → CO 2 + 2H 2 O Zn + 2HCl → H2 + ZnCl2 Zn + 2HCl → H 2 + ZnCl 2 CO2 + H2O → CH2OH + O2 CO 2 + H 2 O → CH 2 OH + O 2 Li2CO3 → LiO + CO2

To determine which chemical equation has the same number of atoms in the reactants as in the products, we must balance each equation and count the number of atoms of each element on both sides.

  1. CH₄ + O₂ → CO₂ + 2H₂O

    • Reactants: C(1) + H(4) + O(2) = 1 + 4 + 2 = 7 atoms
    • Products: C(1) + H(4) + O(2) = 1 + 4 + 2 = 7 atoms
    • The equation is balanced.

  2. Zn + 2HCl → H₂ + ZnCl₂

    • Reactants: Zn(1) + H(2) + Cl(2) = 1 + 2 + 2 = 5 atoms
    • Products: H(2) + Zn(1) + Cl(2) = 2 + 1 + 2 = 5 atoms
    • The equation is balanced.

  3. CO₂ + H₂O → CH₂OH + O₂

    • Reactants: C(1) + O(3) + H(2) = 1 + 3 + 2 = 6 atoms
    • Products: C(1) + O(3) + H(2) = 1 + 3 + 2 = 6 atoms
    • The equation is balanced.

  4. Li₂CO₃ → LiO + CO₂

    • Reactants: Li(2) + C(1) + O(3) = 2 + 1 + 3 = 6 atoms
    • Products: Li(1) + O(1) + C(1) + O(2) = 1 + 1 + 1 + 2 = 5 atoms
    • The equation is not balanced.

From the first three equations, both CH₄ + O₂ → CO₂ + 2H₂O and Zn + 2HCl → H₂ + ZnCl₂ have balanced the number of atoms on both sides.

However, all of these three options list two balanced equations. Still, to specify which statement is entirely satisfactory given the number of atoms matches exactly in a reaction, we can conclude that:

Both CH₄ + O₂ → CO₂ + 2H₂O and Zn + 2HCl → H₂ + ZnCl₂ maintain the number of atoms in reactants equal to that of products.

If only one response is needed without ambiguity on the instruction, any of the first two responses suffice as correctly balanced equations.

true regarding a cheWhich statement ismical reaction?(1 point) Responses The total number of atoms does not change, so mass is conserved in the reaction. The total number of atoms does not change, so mass is conserved in the reaction. The total number of atoms changes, so mass is conserved in the reaction. The total number of atoms changes, so mass is conserved in the reaction. Even if the total number of atoms does not change, mass may not be conserved in the reaction. Even if the total number of atoms does not change, mass may not be conserved in the reaction. Even if the total number of atoms changes, mass may not be conserved in the reaction. Even if the total number of atoms changes, mass may not be conserved in the reaction.

The correct statement regarding a chemical reaction is:

The total number of atoms does not change, so mass is conserved in the reaction.

This reflects the Law of Conservation of Mass, which states that in a closed system, the total mass of the reactants must equal the total mass of the products, meaning that while atoms may be rearranged, the total number of atoms (and thus mass) remains constant throughout the chemical reaction.