Activated carbon, also called activated charcoal, activated coal, or carbo activatus, is a form of carbon processed to be riddled with small, low-volume pores that increase the surface area available for adsorption or chemical reactions. Activated is sometimes substituted with active. Due to its high degree of microporosity, just one gram of activated carbon has a surface area in excess of 500 m, as determined by adsorption isotherms of carbon dioxide gas at room or 0.0 °C temperature.