Q: Given the average bond enthalpy for the O=O double bond is $$495\ \mathrm{kJ/mol}$$, what is the minimum energy (in joules) required to break a single O=O bond in one molecule of $$O_2$$?

$$8.22 \times 10$$^{-19}$$\ \mathrm{J}$$

Q: Which of the following reactions represents the photodissociation of molecular oxygen in the upper atmosphere?

$$O_2(g) + h$$\nu \rightarrow 2O(g)$$

Question 1

Which atmospheric layer contains the majority of Earth's weather phenomena and has a temperature that generally decreases with altitude?

Accepted Answer

Troposphere

Question 2

Given the average bond enthalpy for the O=O double bond is $$495\ \mathrm{kJ/mol}$$, what is the minimum energy (in joules) required to break a single O=O bond in one molecule of $$O_2$$?

Accepted Answer

$$8.22 	imes 10$$^{-19}$$\ \mathrm{J}$$

Question 3

Which of the following best describes photodissociation in the upper atmosphere?

Accepted Answer

The rupture of a chemical bond in a molecule due to absorption of a photon

Question 4

The energy of a photon is given by $$E = h
u. If $$the frequency of light is doubled, what happens to the energy of the photon?

Accepted Answer

It is doubled

Question 5

Which process is primarily responsible for the formation of atomic oxygen in the upper atmosphere?

Accepted Answer

Photodissociation of $$O_2$$

Question 6

If the bond dissociation energy for the C–Cl bond in $$CF_2Cl_2 is$$ $$339\ \mathrm{kJ/mol}$$, what is the maximum wavelength (in nm) of light that can break this bond? ($$h = 6.63 	imes 10$$^{-34}$$\ \mathrm{J\cdot s}$$, $$c = 3.00 	imes 10^8$\ \mathrm{m/s}$$, $$1\ \mathrm{mol} = 6.022 	imes 10$$^{23}$$ molecules)

Accepted Answer

$$353\ \mathrm{nm}$$

Question 7

Which of the following is a correct net reaction for the catalytic destruction of ozone by chlorine atoms in the stratosphere?

Accepted Answer

$$2O_3(g) \rightarrow 3O_2(g)$$

Question 8

Which of the following statements about the composition of Earth's atmosphere is correct?

Accepted Answer

Nitrogen and oxygen together make up more than 99% of dry air near sea level

Question 9

Which of the following is a direct consequence of the absorption of ultraviolet radiation by ozone in the stratosphere?

Accepted Answer

Protection of living organisms from harmful UV radiation

Question 10

Which of the following best explains why the ozone layer is primarily found in the stratosphere and not in the troposphere?

Accepted Answer

The required UV radiation for ozone formation is absorbed before reaching the troposphere

Question 11

Which of the following reactions represents the photodissociation of molecular oxygen in the upper atmosphere?

Accepted Answer

$$O_2(g) + h$$
u ightarrow 2O(g)$$

Question 12

Which of the following is a correct statement about the relationship between wavelength and energy of electromagnetic radiation?

Accepted Answer

Shorter wavelength corresponds to higher energy

Question 13

Which of the following is a real-world consequence of ozone depletion in the stratosphere?

Accepted Answer

Increased incidence of skin cancer in humans

Question 14

Which of the following is a correct description of photoionization?

Accepted Answer

A molecule absorbs a photon and loses an electron, forming a cation

Question 15

Which of the following best explains why CFCs (chlorofluorocarbons) are particularly effective at depleting stratospheric ozone?

Accepted Answer

CFCs release chlorine atoms upon photodissociation in the stratosphere, which catalyze ozone destruction

Question 16

Which of the following is the correct order of atmospheric layers from Earth's surface upward?

Accepted Answer

Troposphere, Stratosphere, Mesosphere, Thermosphere

Question 17

Which of the following is a correct application of the equation $$E = \dfrac{hc}{\lambda}$$?

Accepted Answer

To calculate the energy of a photon given its wavelength

Question 18

Which of the following is a plausible reason why the presence of trace gases like ozone and carbon monoxide, despite their low concentrations, is significant in the atmosphere?

Accepted Answer

They can have profound environmental and health impacts

Ch 18: Chemistry of the Environment: Earth's Atmosphere and Atmospheric Chemistry

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