Question

Which statement is true regarding a chemical reaction?

1. Even if the total number of atoms changes, mass may not be conserved in the reaction.
2. The total number of atoms changes, so mass is conserved in the reaction.
3. Even if the total number of atoms does not change, mass may not be conserved int the reaction.
4. The total number of atoms does not change, so mass is conserved in the reaction.

Answer 1

[AI-generated answer — Bot GPT 3.5]

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

Answer 2

[AI-generated answer — Step-by-Step Bot]

The correct statement is option 1: Even if the total number of atoms changes, mass may not be conserved in the reaction.

Answer 3

[AI-generated answer — Explain Bot]

To determine which statement is true regarding a chemical reaction, we need to understand the concept of mass conservation.

According to the law of conservation of mass, mass is neither created nor destroyed in a chemical reaction. This means that the total mass of the reactants must equal the total mass of the products.

Now, let's analyze each statement:

1. "Even if the total number of atoms changes, mass may not be conserved in the reaction." This statement is incorrect. If the total number of atoms changes, mass must still be conserved. Changes in the arrangement or composition of atoms may occur, but the total mass must remain the same.

2. "The total number of atoms changes, so mass is conserved in the reaction." This statement is also incorrect. While the total number of atoms can change during a chemical reaction, it does not necessarily guarantee mass conservation. Mass conservation is determined by the total mass of the reactants being equal to the total mass of the products.

3. "Even if the total number of atoms does not change, mass may not be conserved in the reaction." This statement is correct. If the total number of atoms does not change, mass should be conserved, but there are exceptions. For example, in nuclear reactions, a small amount of mass can be converted into energy according to Einstein's famous equation, E=mc².

4. "The total number of atoms does not change, so mass is conserved in the reaction." This statement is incorrect because it assumes that mass is always conserved when the total number of atoms remains constant. However, as discussed in statement 3, there are exceptions to this rule.

Therefore, the correct statement is number 3: "Even if the total number of atoms does not change, mass may not be conserved in the reaction."