* not completed

. Which of the following conditions is/are needed for photochemical smog formation? (Please select all that apply)

A stable atmosphere correct incorrect

Warm or hot temperatures correct incorrect

Emissions of nitrous oxide correct incorrect

Intense sunlight correct incorrect

Emissions of volatile organic compounds correct incorrect

* not completed

. Which of the following reactions is/are part of the smog generation sequence? (Please select all that apply)

O₂ + hν → O + O correct incorrect

NO₂ + hν → NO + O correct incorrect

O* + H₂O → 2 •OH correct incorrect

NO₂ + H₂O → NO + 2 •OH correct incorrect

O₃ + hν → O₂* + O* correct incorrect

* not completed

. Ethanol, produced as a biofuel, has the following advantage(s) over petroleum fuels: (Please select all that apply)

It is an oxygenating fuel, promoting more complete combustion correct incorrect

It produces more energy per volume than petroleum-based fuels  correct incorrect

During combustion it releases less CO than petroleum-based fuels correct incorrect

It is produced from a renewable resource correct incorrect

Reduced volatility means reduced release of VOCs from the gas tank correct incorrect

* not completed

. Which of these compounds is/are part of the smog-generating sequence? (Please select all that apply)

NO₂ correct incorrect

NO correct incorrect

N₂O correct incorrect

CO correct incorrect

O₃   correct incorrect

* not completed

. Which of the following statements about smog formation is/are true? (Please select all that apply)

Both thermal and photochemical reactions are involved in creating a photochemical smog correct incorrect

Sulfur compounds from coal burning are a major contributor to photochemical smog correct incorrect

Natural gas, as a fuel, does not contribute to emission of smog-producing chemicals correct incorrect

An atmospheric inversion means that cooler air is present near the Earth's surface correct incorrect

Components of both classical and photochemical smog can be present together correct incorrect

* not completed

. Which of the following statements about smog formation is/are true? (Please select all that apply)

Carbon monoxide oxidation is a part of the photochemical smog formation reaction sequence correct incorrect

Fuels high in nitrogen content are the source of nitrous oxide emitted from automobiles correct incorrect

Photolysis of nitrogen dioxide produces atomic oxygen that is a precursor of ozone correct incorrect

Hydroxyl radical concentrations are generally higher in tropical atmospheres than in temperate ones correct incorrect

Peroxy radicals are part of the reaction sequence that leads to oxidation of hydrocarbons correct incorrect

* not completed

. Which of the following statements about smog formation is/are true? (Please select all that apply)

Reactions of hydroxyl radical with olefins usually begin with abstraction of a hydrogen atom correct incorrect

Phenols are one product of the oxidation of aromatic compounds in the atmosphere correct incorrect

Peroxy species react with nitrous oxide to form nitrate ion correct incorrect

PANs act as relatively stable reservoirs of nitrogen oxides correct incorrect

For hydrocarbons, hydroxyl radicals are the most important initiator of the smog reaction sequence correct incorrect

* not completed

. Which of the following statements about VOC oxidation is/are true? (Please select all that apply)

For alkynes, the initial reaction step in their oxidation is to add a hydroxyl at the triple bond correct incorrect

Aldehydes are involved in the formation of PANs correct incorrect

Hydrogen abstraction or hydroxyl addition to a VOC both lead to formation of radicals correct incorrect

Photolysis of aldehydes in the atmosphere leads to immediate production of carbon dioxide correct incorrect

In an urban atmosphere, hydrocarbon concentrations tend to decrease during the day correct incorrect

* not completed

. Which of the following statements about internal combustion engines is/are true? (Please select all that apply)

Using fuels with a high octane number increases the compression ratio of the engine correct incorrect

Large air to fuel ratios in an engine increases production of nitric oxide correct incorrect

The fuel additive, tetraethyl lead, by acting as an oxygenating agent, is used to augment the octane number of gasoline correct incorrect

The compression ratio equals the work done by an engine over the heat input correct incorrect

Both rich and lean fuel/air ratios can lead to production of photochemical smog precursors correct incorrect

* not completed

. Which of the following statements about internal combustion engines is/are true? (Please select all that apply)

In two-stroke engines, mixing of exhaust gases and fresh fuel/air mixtures occurs correct incorrect

Nitric oxide production is intrinsically greater in a diesel compared to a gasoline engine correct incorrect

Catalytic converters are available that can simultaneously reduce emissions of nitric oxide and VOCs from a gasoline engine correct incorrect

Biodiesel fuels generate lower concentrations of partially-burned carbon-containing products than petroleum diesel correct incorrect

It is not possible to use emission catalysts to reduce harmful exhaust gases from a two-stroke engine correct incorrect