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Problem 1b
At 273 K and 1 atm pressure, 1 mol of an ideal gas occupies 22.4 L. (Section 10.4) (b) Looking at Figure 18.1, we see that the temperature is lower at 85 km altitude than at 50 km. Does this mean that one mole of an ideal gas would occupy less volume at 85 km than at 50 km? Explain.
Problem 1c
At 273 K and 1 atm pressure, 1 mol of an ideal gas occupies 22.4 L. (Section 10.4) (c) In which parts of the atmosphere would you expect gases to behave most ideally (ignoring any photochemical reactions)? [Section 18.1]
Problem 3d
The figure shows the three lowest regions of Earth's atmo- sphere.
(d) An aurora borealis is due to excitation of atoms and molecules in the atmosphere 55–95 km above Earth's surface. Which regions in the figure are involved in an aurora borealis?
Problem 4
Where does the energy come from to evaporate the esti- mated 425,000 km3 of water that annually leaves the oceans, as illustrated here? [Section 18.3]
- In the following instances, which choice is greener in a chemical process and why? (b) A reagent for the reaction that can be obtained from corn husks or one that is obtained from petroleum. (c) A process that produces no by-products or one in which the by-products are recycled for another process.
Problem 5
- It was estimated that the eruption of the Mount Pinatubo volcano resulted in the injection of 20 million metric tons of SO2 into the atmosphere. Most of this SO2 underwent oxidation to SO3, which reacts with atmospheric water to form an aerosol. The aerosols caused a 0.5 to 0.6 °C drop in surface temperature in the northern hemisphere. What is the mechanism by which this occurs?
Problem 6
Problem 9a
(a) What is the primary basis for the division of the atmosphere into different regions?
Problem 10a
(a) How are the boundaries between the regions of the atmosphere determined?
Problem 10b
(b) Explain why the stratosphere, which is about 35 km thick, has a smaller total mass than the troposphere, which is about 12 km thick.
Problem 11a
Air pollution in the Mexico City metropolitan area is among the worst in the world. The concentration of ozone in Mexico City has been measured at 441 ppb (0.441 ppm). Mexico City sits at an altitude of 7400 feet, which means its atmospheric pressure is only 0.67 atm. (a) Calculate the partial pressure of ozone at 441 ppb if the atmospheric pressure is 0.67 atm.
Problem 11b
Air pollution in the Mexico City metropolitan area is among the worst in the world. The concentration of ozone in Mexico City has been measured at 441 ppb (0.441 ppm). Mexico City sits at an altitude of 7400 feet, which means its atmospheric pressure is only 0.67 atm. (b) How many ozone molecules are in 1.0 L of air in Mexico City? Assume T = 25 °C.
Problem 12
From the data in Table 18.1, calculate the partial pressures of carbon dioxide and argon when the total atmospheric pressure is 1.05 bar.
- The average concentration of carbon monoxide in the air in an Ohio city in 2006 was 3.5 ppm. Calculate the number of CO molecules in 1.0 L of this air at a pressure of 759 torr and a temperature of 22 °C.
Problem 13
- (b) What is the concentration of neon in the atmosphere in molecules per liter, assuming an atmospheric pressure of 730 torr and a temperature of 296 K?
Problem 14
Problem 15a
The dissociation energy of a carbon-bromine bond is typically about 276 kJ/mol. (a) What is the maximum wavelength of photons that can cause C-Br bond dissociation?
- In CF3Cl, the C-Cl bond dissociation energy is 339 kJ/mol. In CCl4, the C-Cl bond dissociation energy is 293 kJ/mol. What is the range of wavelengths of photons that can cause C-Cl bond rupture in one molecule but not in the other?
Problem 16
Problem 17b
(b) Use the energy requirements of these two pro- cesses to explain why photodissociation of oxygen is more important than photoionization of oxygen at altitudes below about 90 km.
Problem 19a
The wavelength at which the O2 molecule most strongly absorbs light is approximately 145 nm. (a) In which region of the electromagnetic spectrum does this light fall?
Problem 20b
The ultraviolet spectrum can be divided into three regions based on wavelength: UV-A (315–400 nm), UV-B (280–315 nm), and UV-C (100–280 nm). (b) In the absence of ozone, which of these three regions, if any, are absorbed by the atmo- sphere?
- Do the reactions involved in ozone depletion involve changes in the oxidation state of the O atoms? Explain.
Problem 21
Problem 22
Which of the following reactions in the stratosphere cause an increase in temperature there? (a) O(g) + O2(g) → O3+(g) (b) O3*(g) + M(g) → O3(g) + M*(g) (c) O2(g) + hv → 2 O(g) (d) O(g) + N2(g) → NO(g) + N(g) (e) All of the above
Problem 23
(a) What is the difference between chlorofluorocarbons and hydrofluorocarbons?
- Draw the Lewis structure for the chlorofluorocarbon CFC-11, CFCl3. What chemical characteristics of this substance allow it to effectively deplete stratospheric ozone?
Problem 24
- The average bond enthalpies of the C ¬ F and C ¬ Cl bonds are 485 kJ/mol and 328 kJ/mol, respectively. Given the fact that O2, N2, and O in the upper atmosphere absorb most of the light with wavelengths shorter than 240 nm, would you expect the photodissociation of C ¬ F bonds to be significant in the lower atmosphere?
Problem 25
Problem 26a
(a) When chlorine atoms react with atmospheric ozone, what are the products of the reaction?
Problem 26b
(b) Based on average bond enthalpies, would you expect a photon capable of dissociating a C-Cl bond to have sufficient energy to dissociate a C-Br bond?
- Nitrogen oxides like NO2 and NO are a significant source of acid rain. For each of these molecules, write an equation that shows how an acid is formed from the reaction with water.
Problem 27
Problem 29b
(b) If a limestone sculpture were treated to form a surface layer of calcium sulfate, would this help to slow down the effects of acid rain? Explain.
Problem 31b
Alcohol-based fuels for automobiles lead to the production of formaldehyde (CH2O) in exhaust gases. Formaldehyde undergoes photodissociation, which contributes to photo- chemical smog: CH2O + hn ¡ CHO + H The maximum wavelength of light that can cause this reaction is 335 nm. (b) What is the maximum strength of a bond, in kJ/mol, that can be broken by absorption of a photon of 335-nm light?
Problem 31d
Alcohol-based fuels for automobiles lead to the production of formaldehyde (CH2O) in exhaust gases. Formaldehyde undergoes photodissociation, which contributes to photo- chemical smog: CH2O + hn ¡ CHO + H The maximum wavelength of light that can cause this reac- tion is 335 nm. (d) Write out the formaldehyde photodis- sociation reaction, showing Lewis-dot structures.