You conduct an experiment in the laboratory to find the breakpoint of a water sample. Testing shows that breakpoint occurs in a sample for which you added 1.0 mg of Cl2 to a 150 mL sample of water. Assuming the demand comes from ammonia (and not other reducing substances), what is the ammonia concentration of the water? (provide you answer in numerical format with 2 significant figures; for example 22, 2.2, 0.22, 0.022)