When water boils, what is released?

When water boils, what is released?

• A. Carbon dioxide
• B. Oxygen
• C. Water vapor
• D. Nitrogen

Answer: (C)

When a liquid boils, heat energy allows water molecules to break free from the liquid and enter the gas phase. This makes steam, or water vapor, the substance that is released during boiling. So, water vapor is produced as the liquid water becomes gas. The other gases—carbon dioxide, oxygen, and nitrogen—are not generated by boiling water; they are common components of air or produced by other processes, not by the boiling of pure water.

When a liquid boils, heat energy allows water molecules to break free from the liquid and enter the gas phase. This makes steam, or water vapor, the substance that is released during boiling.

So, water vapor is produced as the liquid water becomes gas. The other gases—carbon dioxide, oxygen, and nitrogen—are not generated by boiling water; they are common components of air or produced by other processes, not by the boiling of pure water.