WHICH OF THE FOLLOWING WILL HAVE ITS MASS INCREASED WHEN HEATED IN AIR

• A. Helium
• B. Magnesium ✓
• C. Copper pyrites
• D. Glass

When heated in air, magnesium will undergo a chemical reaction known as combustion. During this process, magnesium reacts with oxygen in the air to form magnesium oxide. The mass of the magnesium will increase as it combines with oxygen from the air to form the heavier magnesium oxide.

The additional mass comes from the oxygen atoms that combine with magnesium during this process.