1. Practice Test #2 – September 2005

2. The trace greenhouse gases: methane, nitrous oxide, and CFCs will likely have a combined effect comparable to CO 2 because of (a) their absolute levels of emission (b) their efficiency of radiation trapping (c) their atmospheric lifetime (d) all of these. Answer (d) all of these Which of the following species absorbs infrared radiation in the troposphere? a. N 2 b. O 2 c. CO 2 d. Ar Answer c. CO 2 The oxidation state of sulfur (S) in SO 4 2- is: (a) +6 (b) +4 (c) +2 (d) 0 Answer (a) +6

3. Which of the following reactions is representative of hydroxyl free radical chemistry? (a) CHCl 3 + OH ---------> CHCl 2 OH + Cl (b) CHCl 3 + OH ----------> CHCl 2 + HCl (c) OH(g) + NO 2 (g)-------M-----> HNO 3 (g) (d) CHCl 3 + OH -----------> CH 2 OCl + Cl 2 Answer (c) OH(g) + NO 2 (g)-------M-----> HNO 3 (g) Which of the following reactions is not necessary in the major route for the formation of the hydroxyl radical in the troposphere? (a)NO 2 ----h, NO + O (b)O 2 + NO 2 -----------------> NO + O 3 (c) O 3 -------h, O 2 * + O* (d)O* + H 2 O ----------> 2 OH (where O* is an excited oxygen atom) Answer (b)O 2 + NO 2 -----------------> NO + O 3

4. Which of the following is not a reaction in the oxidizing of H 2 S to SO 3 (a) HS + O 2 -----> HSO 2 (b) HSO 3 + OH -----> SO 3 + H 2 O (c) HSO 2 + NO ----> NO 2 + HSO (d) HS + NO 2 ------> HSO + NO Answer (d) HS + NO 2 ------> HSO + NO The most common fate of peroxy radicals in tropospheric air, except of the very cleanest of air as that over the ocean, is illustrated in which of the following reactions: (a) HSO 3 + NO-------->NO 2 +HSO 2 (b) H 2 O 2 ----------->H 2 + O 2 (c) CH 3 COO + OH ----------> CH 3 COH + O 2 (d) HSO 2 + OH -------->H 2 SO 3 Answer: (a) HSO 3 + NO--------> NO 2 +HSO 2

5. This figure shows the experienced temperatures during the period 1860 to 1990 and the computer model. What are the limitations and criticisms of current modeling programs? The main criticism is that the models can not reproduce past results, so how can they be expected to predict the future. Another variable is the inability to know how to handle ‘clouds’ in future modeling.

6. When comparing CO 2 and CF 2 Cl 2, the global warming potential per molecule for CF 2 Cl 2 is 4000 times greater than CO 2. Please explain When comparing the two molecules, one sees immediately that CF 2 Cl 2 has nine degrees of vibrational motion compared to four degrees for CO 2. That coupled with a residence lifetime significantly greater than CO 2 resuls in a global warming potential per molecule that is 4000 times greater than CO 2.

7. Indicate which of the following reactions is possible in the stratosphere. There is more than one. (a) ClO + O 2  Cl + O 3 (b) O 3 + O  2 O 2 (c) NO + ClO  Cl + NO 2 (d) NO 2 + O 2  NO + O 3 (e) O 2 + Cl  ClO + O The secret is to look at the reverse reaction and determine if it will go spontaneously, for example (d) will NO take the “loose” oxygen from O 3 – yes, so as the reaction is written it will not occur. NO

8. Using the decision trees (attached), show how CH 4 is ultimately oxidized to CO 2 in the troposphere. CH 4 + OH  CH 3 + HOH CH 3 + O 2  CH 3 O 2 CH 3 O 2 + NO  NO 2 + CH 3 O CH 3 O + O 2  CH 2 O + O 2 H CH 2 O + OH  CHO + H 2 O CHO + O 2  CHO 3 CHO 3 + NO  NO 2 + CHO 2 CHO 2 +O 2  CO 2 + HO 2

9. The United Nations Report (January, 1996) cited four things that have been happening during the last 100 years that they attribute to global warming. List two of these. Melting of glaciers in Europe Raising of sea level Bleaching of coral reefs Global temperatures have been rising

10. Why has the International Treaty Agreement reducing the CO 2 emissions been opposed by the US Senators? Answer: They want the developing countries, specifically China and India to agree to the terms of the Treaty.