An absorption column is used to separate out components of a rising gas with the use of a falling liquid to adsorb or react with a component(s) of the gas. In our absorption tower, the gas goes in at the bottom of the tower. It, along with any impurities it contains, begins to flow to the top. As it moves toward the top, liquid is sprayed into the tower wetting the packing material. The wet surfaces and droplets catch impurities in the gas and carry them to the bottom of the tower for collection. Students experimentally determine the concentration of the transferred solute in this liquid and compare this data to predictions based on mass transfer theoretical value and also to the solubility limit.