Which of the following statements about conservation of mass is true?
Mass is conserved in physical changes, but not chemical changes.
• In a chemical reaction, the mass of the reactants is always greater than the mass of the products.
• In a chemical reaction, the mass of the products is always greater than the mass of the reactants.
• Mass is conserved in both physical and chemical changes.
• Mass is conserved in both physical and chemical changes.
The correct statement about the conservation of mass is:
- Mass is conserved in both physical and chemical changes.
The correct statement about conservation of mass is:
Mass is conserved in both physical and chemical changes.
To determine the correct answer, we first need to understand the concept of conservation of mass. Conservation of mass is a fundamental principle in chemistry, which states that the total mass of a closed system remains constant before and after any physical or chemical changes. This means that the total mass of all substances involved in a process remains the same, regardless of the nature of the change.
Now let's analyze each statement to identify the correct one:
1. Mass is conserved in physical changes, but not chemical changes.
This statement is incorrect. Conservation of mass applies to both physical and chemical changes. In physical changes, such as melting or cutting a substance, the mass of the original material remains the same. The arrangement of particles might change, but the total mass remains constant.
2. In a chemical reaction, the mass of the reactants is always greater than the mass of the products.
This statement is false. In a chemical reaction, the total mass of the reactants is equal to the total mass of the products. Mass cannot be created or destroyed during a chemical reaction; it is merely rearranged.
3. In a chemical reaction, the mass of the products is always greater than the mass of the reactants.
This statement is false as well. As mentioned above, the total mass of the products is equal to the total mass of the reactants in a chemical reaction. There is no net gain or loss of mass.
4. Mass is conserved in both physical and chemical changes.
This statement is correct. Mass is indeed conserved in both physical and chemical changes. The total mass of a system remains constant irrespective of the type of change that occurs.
Therefore, the correct statement is: Mass is conserved in both physical and chemical changes.