questions: atmospheric and green Flashcards
if the pressure is 0.01 atm at an altitude of 38 km and 0.001 at 57 km, what is it at 19km (ignoring temperature variations)?
The equation relating pressure at a given altitude, Ph is a log function of the altitude, h. Since Ph decreases by 1 log unit (factor of 10) for an increase in altitude of 19 km from 38 km to 57 km, it would be higher by a factor of 10 at an altitude 19 km lower than 38 km at 19km. Therefore, at 19km the pressure would be 0.1 atm
of the species O, HO., NO2, H3C., and N+, which could most readily revert to a nonreactive, “normal” species in total isolation?
-NO2* because it is an excited state of the NO2 molecule and could revert to the stable ground state by emitting a photon. Each of the other species would have to react with something else to become a stable species which could not happen in total isolation
state two factors that make the stratosphere particularly important in terms of acting as a region where atmospheric trace contaminants are converted to other, chemically less reactive forms.
the stratosphere is exposed to intense ultraviolet radiation that causes photodissociation of molecules and generates species such as O atoms that can react with molecules. At lower altitudes in the troposphere this intense flux of ultraviolet radiation is not presence. Few species reach the altitudes above the stratosphere where they could react
what is the distinction between the symbols * and . in discussing chemically active species in the atmosphere?
the * symbol denotes an excited state and . denotes a free radical with an unpaired electron
A-3
B-1
C-2
D-4
A-3
B-4
C-1
D-2
A
what are some uses of organic solvents other than for reaction media? what are some of the drawbacks of organic solvents for these uses?
in addition to serving as media for organic reactions, organic solvents are used to carry organic-soluble reagents to a reaction medium, as vehicles in paints and coatings, and for cleaning parts
-major disadvantages of organic solvents in these applications are their tendencies to evaporate and pollute air and their toxic nature
-the purification of spent solvents and the destruction and disposal of residues left from the distillation of spent solvents may also present challenges
in terms of interactions with reagents, what is the greatest disadvantage of water as a solvent? what is the greatest advantage of water as a solvent for a variety of solutes of biological origin?
water is a poor solvent for many organic reagents and may react with some reagents, largely by hydrolysis reactions
-a big advantage of water for solutes of biological origin is that these materials are largely created in a water medium by biochemical reactions and are compatible with water
how is atom economy defined? in what sense is it a key aspect of the practice of green chemistry?
atom economy is the fraction of reactant material that actually ends up in final product
-achievement of a high degree of atom economy ensures most efficient utilization of reagents and minimum production of waste making it a key aspect of the practice of green chemistry
look up the phenomenon of mineralization as it occurs in biological ecosystems. Name and describe a process analogous to mineralization that occurs in an industrial ecosystem
mineralization refers to biodegradation processes in which often complex organic materials are broken down to simple inorganic substances such as carbon dioxide from organic carbon, ammonium ion from organic nitrogen and phosphate from organophosphorus compounds
-an analogy in an industrial ecosystem would be production of iron from steel in car bodies or aluminum metal from aluminum beverage cans
how are the terms industrial metabolism, industrial ecosystem, and sustainable development related to industrial ecology?
industrial ecology practiced in industrial ecosystems where materials undergo industrial metabolism
-sustainable development refers to the utilization of materials, energy and resources in a way that minimizes their depletion such as by using renewable materials (for example biomass feedstocks), renewable energy (for example wind energy) and recycling of materials
from the definition of symbiosis, explain what is meant by industrial symbiosis. How is industrial symbiosis related to industrial ecology?
in nature, symbiosis refers to two or more organisms that function to mutual advantage, such as the algae and fungi present in lichens that grow on rocks
-substitution of industrial enterprises for organisms in this definition defines industrial symbiosis, which is an integral part of the practice of industrial ecology
what are the enterprises that serve to underpin the Kalungborg industrial ecosystems? how might they compare with the basic enterprises of an industrial ecosystem consisting of rural counties in the state of Iowa?
the two main enterprises in the Kalundborg industrial ecosystems are a large coal-fired electrical plant and a large petroleum refinery
-an industrial ecosystem in a rural area could consist of agricultural land devoted to growing biomass, livestock feeding operations using the biomass food source, methane-producing anoxic digesters to produce high-quality fuel from livestock wastes, and biorefineries to refine chemical products from thermally treated biomass
how does “design for recycling” (DFR) relate to embedded utility?
as shown in figure 17.11 illustrating an “energy/materials pyramid”, significantly less energy, and certainly no more materials, are involved when recycling is performed near the top of the materials flow chain rather than near the bottom. The more efficient recycling near the top of the pyramid can be facilitated when components are designed to facilitate recycling
