The osmotic pressure exerted by seawater at 25°C is about 27 atm. Calculate the concentration of ions dissolved in seawater that is needed to give an osmotic pressure of this magnitude. (Desalinization of seawater is accomplished by reverse osmosis. In this process an applied pressure forces water through a membrane against a concentration gradient. The minimum external force needed for this process will be 27 atm. Actually, to accomplish the process at a reasonable rate, the applied pressure needs to be about twice this value.)