Problem 39
Dinitrogen monoxide, \(\mathrm{N}_{2} \mathrm{O}\) (commonly called nitrous oxide), is prepared by the careful decomposition of ammonium nitrate and is used as an oxidizing agent in rocket engines as well as a weak general anesthetic (where you may know it as "laughing gas".). However, it is also known to be a powerful greenhouse gas. In a Science magazine article, it was stated that "Human activities may be causing an unprecedented rise in the terrestrial \(\mathrm{N}_{2} \mathrm{O}\) source. Marine \(\mathrm{N}_{2} \mathrm{O}\) production may also rise substantially as result of eutrophication, warming, and ocean acidification." \([\mathrm{L} . \text { A. Codispoti, } \text {Science}\), Vol. \(327, \text { pp. } 1339-1340,2010 .]\) (a) Draw a Lewis electron dot structure for \(\mathrm{N}_{2} \mathrm{O}\) and specify the formal charge on each atom and the molecular geometry. (b) The atom connections are \(\mathrm{N}-\mathrm{N}-\mathrm{O} .\) Why is the connection \(\mathrm{N}-\mathrm{O}-\mathrm{N}\) not likely? (c) The highest \(\mathrm{N}_{2} \mathrm{O}\) concentration observed in the ocean is about 800 nM (nanomolar). At this concentration, what is the mass of \(\mathrm{N}_{2} \mathrm{O}\) per liter?
Problem 40
In \(2005,\) global \(\mathrm{SO}_{2}\) emission was estimated to be \(12.83 \mathrm{Gg}\) (gigagrams). According to the \(\mathrm{EPA}, 71 \%\) of \(\mathrm{SO}_{2}\) emissions into the atmosphere is from coal-fired power plants. How much coal (in metric tons) must have been burned to produce this much \(\mathrm{SO}_{2}\) assuming that coal is \(2.0 \%\) sulfur?
Problem 42
The refrigerating liquids in air conditioners and refrigerators are largely chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Among the latter family of compounds is the refrigerant HCFC-22 \(\left(\mathrm{HCClF}_{2}\right)\). A problem with the use of HCFC-22 is that HFC-23 (trifluoromethane, HCF \(_{3}\) ), a gas with high-global-warming potential, is a byproduct of its production (and also from the production of the widely used polymer Teflon). Discarding HFC-23 safely can be a problem. However, recently a method has been developed to convert it to the valuable catalyst trifluoromethanesulfonic acid, \(\mathrm{CF}_{3} \mathrm{SO}_{3} \mathrm{H}\). Draw an electron dot structure for the acid (which you can think of as sulfuric acid with a \(\mathrm{CF}_{3}\) group in place of one OH group). Indicate the geometry around the \(\mathrm{C}\) and \(\mathrm{S}\) atoms. What is the hybridization of these two atoms?
Problem 43
Chlorine atoms are formed by photochemical reactions of chlorofluorocarbons in the upper atmosphere. Using the average bond energy of the \(\mathrm{C}-\mathrm{Cl}\) bond in Table \(8.8,\) calculate the wavelength of radiation with sufficient energy to break the \(\mathrm{C}-\mathrm{Cl}\) bond. In what region of the electromagnetic spectrum does this fall?
Problem 46
Steps have been taken to limit phosphorus in surface water. However, the amounts of nitrogen-containing species in surface water can also be a problem because they also promote excessive growth of algae and water plants. What are likely sources of this nitrogen? What nitrogen compounds are likely to be present in surface water?
Problem 49
Imagine the following experiment: You have a large graduated cylinder containing 100. mL of liquid water at \(0^{\circ} \mathrm{C}\). You drop an ice cube with a volume of \(25 \mathrm{cm}^{3}\) into the cylinder. Ice has a density of \(0.92 \mathrm{g} / \mathrm{cm}^{3},\) less than the density of liquid water, so it floats with \(92 \%\) being under water. (a) To what level will the water in the graduated cylinder rise after adding the ice? (b) Allow the ice to melt. What volume will now be occupied by the liquid water? (One consequence of global warming will be a rise in sea level as ice in the northern and southern regions of the planet melts. However, the effect relates only to melting of ice on land. Melting of floating ice will have no effect on sea levels.
Problem 50
The mineral claudetite contains the element arsenic in the form of arsenic(III) oxide, \(A s_{2} O_{3}\). The \(A s_{2} O_{3}\) in a \(0.562-g\) sample of the impure mineral was converted first to \(\mathrm{H}_{3} \mathrm{AsO}_{3}\) and then titrated with a \(0.0480 \mathrm{M}\) solution of \(\mathrm{I}_{3}^{-},\) which reacts with \(\mathrm{H}_{3} \mathrm{AsO}_{3}\) according to the following balanced net ionic equation $$\begin{aligned}\mathrm{H}_{3} \mathrm{AsO}_{3}(\mathrm{aq})+3 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{I}_{3}^{-}(\mathrm{aq}) & \rightarrow \\\\\mathrm{H}_{3} \mathrm{AsO}_{4}(\mathrm{aq}) &+2 \mathrm{H}_{3} \mathrm{O}^{+}(\mathrm{aq})+3 \mathrm{I}^{-}(\mathrm{aq})\end{aligned}$$ If the titration required \(45.7 \mathrm{mL}\) of the \(\mathrm{I}_{3}^{-}\) solution, what is the percentage of \(\mathrm{As}_{2} \mathrm{O}_{3}\) in the mineral sample?
Problem 51
Define the terms renewable and nonrenewable as applied to energy resources. Which of the following energy resources are renewable: solar energy, coal, natural gas, geothermal energy, wind power?
Problem 52
What are the three most abundant gases in the atmosphere? Are any of these greenhouse gases?
Problem 53
What are the environmental consequences of ozone in the troposphere? In the stratosphere?
