Wax melts when it is heated. Which most likely describes what is true of the result of this reaction?

The bonding of the atoms is not the same before and after the change.
The wax has the same density before and after the change.
The same amount of wax exists before and after the change.
The wax cannot be changed back into a solid.

1 answer

The most accurate statement describing what is true of the result when wax melts is:

The same amount of wax exists before and after the change.

This describes the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical or physical change. While the wax changes from a solid to a liquid, its total mass remains constant.

The other options are less accurate for a melting process:

  • The bonding of the atoms is not the same before and after the change: This is misleading; the chemical composition of the wax remains the same, and the melting is a physical change, not a chemical one.
  • The wax has the same density before and after the change: The density may change upon melting, as the volume of the wax changes.
  • The wax cannot be changed back into a solid: This is incorrect; melted wax can solidify again when cooled.