Ozone (o3) is a very reactive gas with a short lifetime. depending on the situation, it can be beneficial or harmful.

a. ozone is used for oxidizing chemicals and inactivating pathogens during water treatment. if 2 mol of ozone is transferred to 100,000 l of water, what is the resulting mass concentration in mg/l?

b. when generated as part of photochemical smog in urban areas, ground-level atmospheric ozone can cause breathing difficulty and aggravate respiratory problems. the united states environmental protection agency has set an eighthour average ozone concentration standard of 0.08 parts per million (ppmv). convert this concentration to units of g/m3 (assume 20 °c and p = 1 atm).

c. in the stratosphere, atmospheric ozone is beneficial in that it prevents harmful short wavelength ultraviolet radiation from reaching the earth’s surface. a typical concentration of atmospheric ozone in the stratosphere is about 15 ppmv. convert this concentration to units of g/m3 (assuming t = -30 °c and p = 10-4 atm).