The earth's ozone layer is under attack in part by chlorine released when ultraviolet radiation breaks apart certain fluorocarbons. Consider three fluorocarbons known as CFC-11 (CCl3F), CFC-12 (CCL2F2), and HCFC-22 (CHF2Cl). (a) Calculate the percentage by weight of chlorine in each of these fluorocarbons. (b) If each kilogram of CFC-11 could be replaced by 1 kg of HCFC-22, by what percentage would the mass of chlorine emissions be reduced?