Carbon dioxide (chemical formula CO2) is a colorless gas with a density about 50% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas at a concentration of about 0.04 percent (400 ppm) by volume. Natural sources include volcanoes, hot springs and geysers, and it is freed from carbonate rocks by dissolution in water and acids. Because carbon dioxide is soluble in water, it occurs naturally in groundwater, rivers and lakes, ice caps, glaciers and seawater. It is present in deposits of petroleum and natural gas. Carbon dioxide is odorless at normally encountered concentrations, however at high concentrations it has a sharp and acidic odor
Carbon dioxide is colorless. At low concentrations the gas is odorless however, at sufficiently-high concentrations, it has a sharp, acidic odor
Carbon dioxide is a food additive used as a propellant and acidity regulator in the food industry. A candy called Pop Rocks is pressurized with carbon dioxide gat about When placed in the mouth, it dissolves (just like other hard candy) and releases the gas bubbles with an audible pop.
Leavening agents cause dough to rise by producing carbon dioxide. Baker’s yeast produces carbon dioxide by fermentation of sugars within the dough, while chemical leaveners such as baking powder and baking soda release carbon dioxide when heated or if exposed to acids.