* At Standard Pressure: Carbon dioxide is typically a gas at standard atmospheric pressure (1 atmosphere).
* Under Pressure: When pressure is increased, the carbon dioxide molecules are forced closer together. If the pressure is high enough (above 5.1 atmospheres), the molecules can transition from a gaseous state to a liquid state.
* Critical Point: There's a specific temperature and pressure point called the critical point where the distinction between liquid and gas phases disappears. For carbon dioxide, the critical point is approximately 31°C (88°F) and 73 atmospheres of pressure. Above this point, carbon dioxide exists in a supercritical fluid state, exhibiting properties of both liquids and gases.
Practical Applications:
* Carbonated Beverages: The carbon dioxide dissolved in carbonated drinks like soda is a liquid under pressure.
* Fire Extinguishers: Some fire extinguishers utilize liquefied carbon dioxide under pressure.
* Supercritical Carbon Dioxide Extraction: This technique utilizes supercritical carbon dioxide to extract valuable compounds from materials.
Key Takeaway: While carbon dioxide is commonly known as a gas, it can transition to a liquid state under sufficient pressure, and even into a supercritical fluid state under specific conditions.
