CHEMISTRY 253
Spring, 2015 - Dixon
Group Assignment #4
Open Book – But 30 min. Time Limit
Group Names _________________________________________________
1. OH is a key reactant to the photochemical production of ozone. (13 pts)
a) Give the two reactions by which it forms in the troposphere including photolysis.
b) In its oxidation reactions (e.g. with CO or hydrocarbons), it will typically give rise to another (relatively stable) radical species. Give an example reaction – list a reactant that reacts with OH and the first product that forms which is O2 stable (will not react with O2). Note that there are usually two reactions before the O2 stable radical forms.
c) Using words or equations, explain how the O2 stable radical contributes to the formation of ozone.
2. A Colorado air pollution control scientist is worried that butane emissions are increasing because of their use in hash oil production (it can be used as a solvent for marijuana extraction). If we assume that the butane emissions are well quantified and that vehicle exhaust is the other big hydrocarbon source (and also well quantified), describe how can we determine if butane emissions are significantly contributing to ozone production. You can further assume that an “average” vehicle exhaust molecule is 1-hexene and that the reaction of butane and 1-hexene with OH is a rate limiting step toward reaction initiation. What other information might be needed to make this assessment? (7 pts)