Question

Which of the following statements best defines the law of conservation of mass?

• A.
  Mass cannot be created but it can be destroyed under extreme pressures.
• B.
  Mass cannot be conserved during a chemical reaction; a little bit of mass is always lost.
• C.
  The mass of a closed system cannot change over time; mass cannot be created nor destroyed.
• D.
  When added to a system, energy can destroy mass.

Answer 1

The correct option is C

The mass of a closed system cannot change over time; mass cannot be created nor destroyed.

The law of conservation of mass states that in a chemical reaction mass is neither created nor destroyed.