What is Dry Ice? Chemical Formula and Uses

The chemical formula of Dry Ice is CO₂. Dry ice is simply solid Carbon Dioxide.

Regular ice (frozen water, H₂O) melts into liquid water when heated. However, solid carbon dioxide (CO₂) does not melt into a liquid under normal atmospheric pressure. When heated, it turns directly from a solid into a gas. This process is called Sublimation. Because it never goes through a 'wet' liquid phase, it is called 'dry' ice.

• Dry ice is extremely cold: its surface temperature is -78.5 °C (-109.3 °F).
• Because of its extreme cold, it must be handled with thick gloves. Touching it bare-handed can cause severe frostbite.
• It is formed by taking CO₂ gas, compressing it to a high pressure, and then cooling it.

1. Cooling: Used to pack and transport frozen food or medical supplies (like vaccines) because it stays cold longer than regular ice and leaves no wet residue.
2. Special Effects: Used in theatres and concerts to create a low-lying, thick 'fog' effect when dropped in hot water.