Practice Test #1 Examples of questions used in the past on Stratospheric chemistry and Urban Air

Convert grams/ liter to ppm grams/1000 grams = 1.0x10 -6 grams solute/gram solution = 1 ppm

Not all XO molecules such as NO 2 survive long enough to react with oxygen atoms; some are photochemically decomposed to X and atomic oxygen, when then reacts with O 2 to reform ozone. Write out the three step (including one for ozone destruction) for this process and add them together to deduce the net reaction. Does this sequence destroy ozone overall or not? XO –    X + O O + O 2  O 3 O 3 + X  XO + O 2 Adding these up gives no change in ozone.

Acid rain continues to be a problem in this country. (a) List two sources of acid rain, (b) two effects of acid rain, and (c) two ways to reduce acid rain. (a) Any source such as sulfur from utility plants, automobiles, industrial processes producing SO 2 and/or NO 2 would be accepted. (b) Acid rain effects vegetation, health, natural waters, and structures (c ) acid rain can be reduced by reducing amount of SO 2 formed, dilution of SO 2, scrubbers, conversion to other products.

In the figure on theright, it is determined that the concentration of ozone, O 3, is at point “A”, 240 ppb. How would you reduce the concentration of ozone to 80 ppb. Be specific, and include actions you would initiate and how you would insure their success. Must reduce either the NO x or VOC until you are on the line corresponding to 80 ppb. To ensure success will require monitoring. A

Multiple Choices 1. (5 pts) When one considers acid rain (a) the gas of principal concern is H 2 S (b) the region influenced must have a high buffering capacity (c )the concentration of the oxide, particularly NO x and SO 2, are critical factors in the ultimate acidity (d) the primary impact is bleaching of coral reefs. (c ) these are the compounds that cause acid rain. (5 pts.) Acid rain (a) does not occur where temperatures are below 18oC (b) causes limestone structures to degrade over time (c )causes an increase in global warming (d) is not a problem in North Carolina (b) Causes limestone structures to degrade over time.

(9. (5 pts) 10 mg/liter is equivalent to: (a) 10 ppm (b) 1 ppm (c) 0.1 ppm (d) 0.01 ppm (e) 10 ppb (a)10 ppm. Which of the following is a radical? a. CCl 3 b. CCl 4 c. N 2 O d. CO (a) CCl 3

5 pts) The concern in southeastern North Carolina regarding nitrogen deposition from hog waste is: a) changing the pH of rivers b) nutrient loading c) regional global warming d) acid rain (b) nutrient loading (5 pts.) In photochemical smog a) sunlight is required to break the ozone and NO 2 bonds b) the hydroxyl radical is not a requirement c) ozone is not a requirement since oxygen atoms will cleave from NO 2 d) the reactions occur more rapidly in colder environments. (a) Sunlight is required to break the ozone and NO 2 bonds

(15 pts) The figure on the right shows the concentrations of ClONO 2 and HCl in the gasous phase over the Antarctic for a twelve month period. Explain how these concentration variances explain the development and recovery of the ozone hole over the Antarctic. Emphasize here the HNO 3 3H 2 O crystals, ClONO 2 and HCl freezing out, HOCl and Cl 2 evaporating, breaking down to give Cl radicals as the sun appears, causing ozone destruction. No new ozone until earth turns and HNO 3 3H 2 O crystals melting and trapping OCl with NO 2, plus new ozone formed.

The figure on the right shows the concentrations of the important pollutants that cause photochemical smog. (a) (5 pts) Identify the pollutants labeled: A = VOCs B=Aldehydes C= Ozone D= [NO] E= [NO 2 ]