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The loss of atmospheric ozone has led to an ozone "hole" over Antarctica. The loss...

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abidi96 | Student, Grade 10 | eNoter

Posted October 6, 2013 at 1:41 AM via web

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The loss of atmospheric ozone has led to an ozone "hole" over Antarctica. The loss occurs in part through three consecutive steps:

(1) Chlorine atoms react with ozone (O3) to form chlorine monoxide and molecular oxygen.

(2) Chlorine monoxide forms ClOOCl.

(3) ClOOCl absorbs sunlight and breaks into chlorine atome and molecular oxygen.

(a)Write a balanced equation for each step.

(b)Write an overall balanced equation for the sequence.

We have to do this for our A.P Chemistry class. I dot know how to do this question. 

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valentin68 | College Teacher | (Level 3) Associate Educator

Posted October 6, 2013 at 3:01 AM (Answer #1)

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a)

1. Chlorine atoms react with ozone (`O_3` ) to form chlorine monoxide and molecular oxygen.

`Cl +O_3 -> ClO + O_2`

2. Chlorine monoxide forms `ClOOCl` .

`2ClO harr Cl_2O_2`

This is an equilibrium reaction and both reactants and products can be found in the upper atmosphere.

3. `ClOOCl` absorbs sunlight and breaks into chlorine atom and molecular oxygen.

`Cl_2O_2 + UV -> 2Cl + O_2`

3'. Because both `Cl_2O_2` and `ClO` can be found in the upper atmosphere there is also a reaction between clorine monoxide and a free atom of oxygen (resulted from decomposition of ozone itself by sunlight into molecular and atomic oxygen)

`(O_3 + UV-> O_2 +O)`

`ClO + O -> Cl +O_2`

0. There is also a first reaction in this chain when a molecule of CFC is decomposed by ultraviolet light

`C Cl_2F_2 + UV-> Cl + C ClF_2`

b)

Therefore the total balanced equation of the above three chemical reactions is

`Cl+2O_3 -> Cl +3O_2`

or by taking into account the original molecule of CFC

`C Cl_2F_2 +2O_3 +UV ->Cl + 3O_2 + C ClF_2`

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abidi96 | Student, Grade 10 | eNoter

Posted October 6, 2013 at 6:17 PM (Answer #2)

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Thankyou! This was extremely helpfull. 

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