What is CO2?

Hi, I’m Emerald Robinson, and in this “What Is” video, we’re going to discuss the molecule Carbon Dioxide.

Carbon dioxide, or “C-O-2”, is naturally found in the form of a colorless, odorless gas on Earth. It is made of three atoms – one carbon atom, and two oxygen atoms. The molecule is held together by covalent bonds, which means electrons are shared between the atoms.

CO2 makes up about four percent of our atmosphere, and it freezes at about minus one hundred ten degrees Fahrenheit. Frozen carbon dioxide is commonly called dry ice. Because it takes such a high pressure to turn carbon dioxide into liquid, when dry ice warms up, it turns directly from a solid to a gas in a process known as sublimation.

Carbon dioxide is a rich source of the element carbon, the most important “building block” for life on earth. Green plants use carbon dioxide during photosynthesis. They turn the carbon into the sugar, glucose, during a process called “fixation.” Animals are then able to use this glucose for energy.

Burning fossil fuels like coal, oil, and natural gas release carbon dioxide into the atmosphere. Over a long period of time, using these fuels has increased the percentage of carbon dioxide in the earth’s atmosphere. This higher concentration causes carbon dioxide to act as a “greenhouse gas.” Greenhouse gases act like glass in a greenhouse by trapping heat below the atmosphere. Scientists think greenhouse gases contribute to global warming.

Carbon dioxide is very useful to humans. It is used to extinguish fires, and it makes the bubbles in soda and other carbonated drinks. Carbon dioxide from yeast and baking soda makes baked goods rise and CO2 even makes the holes in Swiss cheese! The right balance of carbon dioxide is imperative to our survival.