Carbon dioxide
Carbon dioxide in an odorless, colorless gas formed by the combustion of hydrocarbons, both naturally, in the human body, and artificially, as fuel. It is one of the human body's major waste products, being excreted through exhalation. It is used by plants in the process of photosynthesis to generate oxygen.
At room temperature and atmospheric pressure, it is a gas. It becomes solid at -78 ºC at standard atmospheric pressure, forming dry ice. When it thaws, it turns directly into a gas again (see sublimation). [1]
Each molecule of carbon dioxide has one carbon atom and two oxygen atoms, so its chemical formula is CO2.
CO2 is one of the so-called greenhouse gases. Heat-trapping by CO2 has been observed on Earth and Venus. The extent of its role in the current increase in average global temperatures is a topic of active political, though not scientific, debate.
References
- ↑ "Dry ice is frozen carbon dioxide. A block of dry ice has a surface temperature of -109.3 degrees Fahrenheit (-78.5 degrees C). Dry ice also has the very nice feature of sublimation -- as it breaks down, it turns directly into carbon dioxide gas rather than a liquid." How Stuff Works