a) 2NO + 2CO → N
+ 2CO
2
2
→ N
b) NO + C
H
+ CO
+ H
O – unbalanced
6
14
2
2
2
→ N
balance all but O: 2NO + C
H
+ 6CO
+ 7H
O [O is now 2 on left, 19 on right]
6
14
2
2
2
→ N
add NO to balance O: 19NO + C
H
+ 6CO
+ 7H
O [N now not balanced/add to right]
6
14
2
2
2
→ 19/2N
19NO + C
H
+ 6CO
+ 7H
O [finally, multiply all coefficients by 2]
6
14
2
2
2
→ 19N
38NO + 2C
H
+ 12CO
+ 14H
O
6
14
2
2
2
Review Questions: 3-2 to 3-5, 3-7 to 3-10, 1-15, 2-1-2-7, 2-9, 2-12
3-2 What chemical substance initiates the air oxidation of stable molecules? How is it initially
formed, and how is it reformed?
OH is the chemical compound. It is initially formed through the reaction:
O → 2OH (where O* refers to excited – or O(1D) – oxygen atoms
O* + H
2
produced by photolysis of ozone)
It is reformed from HO
(the most common reaction product of oxidation of stable molecules) in
2
the reaction:
+ NO → OH + NO
HO
2
2
3-3 In general terms, what is meant by photochemical smog? What are the initial reactants in
the process? Why is sunlight required?
Photochemical smog is poor quality air formed through a photochemical reactions (including
production of ozone).
The initial reactants are nitrogen oxides and hydrocarbons.
Sunlight is needed to convert NO
to O atoms needed for formation of ozone.
2
3-4 What is meant by a primary pollutant and by a secondary pollutant? Give examples.
A primary pollutant is a pollutant as emitted. A secondary pollutant is formed through
atmospheric reactions. An example of a primary pollutant is CO. An example of a secondary
pollutant is ozone.
3-5 How does OH react with a stable molecule containing a C=C bond? With an alkane?
OH reacts with alkenes through an addition reaction, while it reacts with alkanes through H
atom extraction.
3-7. What is the chemical reaction by which thermal NO is produced?
→ 2NO
N
+ O
2
2
From which two sources does most urban NO arise?
Vehicle emissions and power plant emissions
What is meant by the term NO
?
x
NO is NO
+ NO – the two forms that exist in the atmosphere which interconvert rapidly
2
between each.
What is meant by fuel NO?
Fuel NO is formed from fuel containing nitrogen such as CH
NO
(used in model airplanes and
3
2
for car racing).