* not completed

. Which of these statements is/are true? (Please select all that apply)

The concentration (molecules cm^-3) of ozone molecules decreases with decreasing altitude near the Earth's surface correct incorrect

Ozone in the troposphere is considered to be 'good ozone' correct incorrect

The temperature inversion in the stratosphere minimizes vertical mixing of ozone formed in the lower layers correct incorrect

Stratospheric ozone acts as a filter, screening out high energy UV radiation correct incorrect

The highest mixing ratio of ozone in the atmosphere occurs at approximately 25 km correct incorrect

* not completed

. A measurement of ozone levels gives a value of 155 DU. How many ozone molecules would this represent in a column with a cross sectional area of 1 m², assuming P° and 0°C?

4.17 x 10¹⁸ correct incorrect

4.17 x 10²² correct incorrect

4.17 x 10²⁶ correct incorrect

15.6 x 10¹⁸ correct incorrect

2.40 x 10²³ correct incorrect

* not completed

. Which of the following statements regarding ozone is/are correct? (Please select all that apply)

An odd oxygen species is oxygen that has an unpaired electron. correct incorrect

Solar energy is required for the decomposition but not for the synthesis of ozone           correct incorrect

The reaction between O and O₂ to form ozone has a positive enthalpy correct incorrect

In the process of shielding UV radiation, ozone decomposes to form oxygen correct incorrect

Both c and d are correct correct incorrect

* not completed

. The correct formula for CFC-114b is:

CF₂ClCF₂Cl correct incorrect

CFCl₂CFCl₂ correct incorrect

CF₃ClCFCl correct incorrect

CF₂ClCF₃ correct incorrect

F₃CCF₂Cl   correct incorrect

* not completed

. Which of the following species does not act as a catalyst for ozone decomposition? (unpaired electrons not shown) (Please select all that apply)

OH correct incorrect

H₂ correct incorrect

N₂O correct incorrect

Cl correct incorrect

NO₂ correct incorrect

* not completed

. The first step in the oxygen-only sequence for the decomposition of ozone in the stratosphere is:

O + O₃ → 2O₂ correct incorrect

O₂ + hν → O + O correct incorrect

O₃ + hν → O₂* + O* correct incorrect

O₃ → O₂ + O correct incorrect

O₂ + hν → O* + O* correct incorrect

* not completed

. The initial photochemical step for the decomposition of ozone requires an input of 386.5 kJ mol^-1 of solar energy. To what wavelength does this correspond? (Please select all that apply)

386.5 nm correct incorrect

310 nm correct incorrect

3.1x10^-7 m correct incorrect

3.9x10^-7 m correct incorrect

3.1x10^-16 nm correct incorrect

* not completed

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

Increasing the hydrogen content of a CFC decreases its inertness correct incorrect

Increasing the hydrogen content of a CFC increases its flammability correct incorrect

Replacing Cl atoms with F increases of stability of the molecule correct incorrect

Replacing Cl atoms with F increases the ODP correct incorrect

Increasing the hydrogen content of a CFC reduces the ODP correct incorrect

* not completed

. Which of the following statements about catalytic ozone reactions is/are true? (Please select all that apply)

•OH, •Cl, •H, and NO are all natural radicals that contribute to ozone destruction correct incorrect

Radicals involved in ozone destruction in the first step can be regenerated in a second step correct incorrect

Catalytic destruction of ozone by chlorine-containing species always involve only two steps correct incorrect

Nitrous oxide is a radical species that is produced naturally in soil and water environments correct incorrect

The Chapman series of equations does not correctly account for all ozone destruction correct incorrect

* not completed

. Which of the following statements about the Antarctic 'ozone hole' is/are true? (Please select all that apply)

An 'ozone hole' like that in the Antarctic also forms above the Arctic during the winter, but we can't see it because it is dark correct incorrect

There is actually no 'hole' in the 'ozone layer' but rather a significant decrease in the partial pressure of ozone in the atmosphere above Antarctica correct incorrect

Generally, the concentration of ozone (~250 DU) is similar to values found near the equator, except for a short time around September to November when the amount of ozone decreases to near 100 DU correct incorrect

During the Antarctic winter, the 'structure' of the atmosphere 'disappears' allowing for significant mixing of the gases in the troposphere and stratosphere correct incorrect

Due to the location of the 'ozone hole' above Antarctica, it is not a seen as a threat to people but only to animals in the area correct incorrect