hard water contains ca2 , mg2 , and fe2 , which interfere with the action of soap and leave an insoluble coating on the insides of containers and pipes when heated. water softeners replace these ions with na . keep in mind that charge balance must be maintained. (a) if 1500 l of hard water contains 0.020 m ca2 and 0.0040 m mg2 , how many moles of na are needed to replace these ions? (b) if the sodium is added to the water softener in the form of nacl, how many grams of sodium chloride are needed?
