Chapter 2: Ozone Hole

1 DU is ___mm

0.01mm

1 atm = _____Pa pressure

101325 Pa

What is the size and location of the ozone hole?

220 DU or lower, Antarctica region

The active forms of chlorine related to the ozone hole are __ and __

Cl and CLO

the inactive forms of chlorine are __ and ____

HCl and ClONO₂

each chlorine atom destroys about __ ozone molecules per day during the ____

50, sping

chemical reactions that lead ultimately to zone destruction occur in a thin aqueous layer present at the surface of _______ (PSC) in the form of ___ crystals

polar stratospheric clouds, ice

Write the reaction for gaseous chlorine nitrate (ClONO2) with water to produce hypochlorous acid and HNO3

In the aqueous layer, gaseous hydrogen chloride dissolves and forms ions. Write this reaction

write the first route of how molecular chlorine can be produced:

HOCl (aq), OH-

write the second route of how molecular chlorine, Cl2 can be produced

ClONO2 (g)

most of the ozone hole destruction occurs via mechanism ____

II

Question: A minor route for ozone destruction in the ozone hole involves Mechanism II with bromine as X and chlorine as X ́ (or vice-versa). The ClO and BrO free radical molecules produced in these processes then collide with each other and rearrange their atoms to eventually yield O2 and atomic chlorine and bromine. Write out the mechanism for this process and add up the steps to determine the overall reaction.

The next four card will be about why Mechanism I does not cause ozone hole destruction because it requires ____ oxygen, without a ____ concentration of ____ oxygen, ____(O3) cannot be destroyed.

atomic, high, ozone

in the region where the polar stratospheric clouds (PSCs) form and ____ is activated, the concentration of ___ oxygen atoms is small

chlorine, free

Few atoms are produced there on account of the scarcity of ___ light that is required to dissociate O₂

UV-C

also, any atomic oxygen atoms produced in this way immediately collide with the ___ O2 molecules to form ozone, O3

abundant

CFCs, HFCs, HCFCs, HBFCs and Halons cause _____

ozone destruction

what is the CFC code of CCl₂F₂?

what is the CFC code for C₂Cl₃F₃

deduce the code numbers for CH₃CCl₃

To find the chemical formula given the number/code, first add __ to the abc number, to obtain a 3-digit def number, where d is the # of __ atoms, e is the number of __ atoms, and f is the number of __ atoms

the formula for the number of Cl atoms is?

What is the chemical formula for CFC-11?

What is the chemical formula of CFC-12?

Halons are ____carbons, not hydrofluorocarbons, which means no ___ atoms and at least one __ atom

fluorocarbons, hydrogens, bromine

What is the Halon nomenclature for C₂F₄Br₂?

The increase in stratospheric chlorine is due to the use and release of _____ carbons, which are compounds that contain ___, ___, and ___ which are commonly called CFCs

chlorofluorocarbons, chlorine, fluorine, and carbon

CFCs have no ____ sink, so all molecules of them eventually rise to the ____

tropospheric sink, stratosphere

CFC molecules eventually migrate to the ___ and ___ parts of the stratosphere where the UV-C light _____ decomposes them, thereby releasing ___ atoms.

middle and upper, photochemically, chlorine

CFCs do not absorb sunlight with wavelengths greater than ___ nm, and generally require ___ nm or less for photolysis

290, 220

CFCs must rise to the mid-___ before decomposing since ___ light does not penetrate to lower altitudes

stratosphere, UV-C

At what chlorine level does the Antarctic ozone hole appear?

3 ppb

What are the favorable characteristics of CFC

nontoxic, nonreactive, nonflammable

Which UV light is required to photolysis of CFC?

UV-C light