LaMotte ACID RAIN STUDY OUTFIT ARO - Manual (Page 5)

SUG GES TIONS ON THE USE
OF THE CHEM I CAL TEST EQUIP MENT
A. Follow all of the instructions carefully. Read to the end of each procedure before
starting the actual work. Measure reagents and water samples accurately.
B. Handle the reagents with great care. Avoid contact between the reagents and
the skin and eyes. Some of the reagents are capable of causing minor skin
irritations if they are not washed off immediately after contact. None of the
reagents should be taken internally.
C. Keep all reagent containers tightly capped. Replace the cap immediately after
use. This prevents contamination and eliminates the possibility of loss of the
reagent due to leakage or spilling. Do not interchange caps.
D. The test tubes should be rinsed thoroughly in clean tap water and allowed to dry
before putting them back into the package. No soap or detergents are required
unless there are stubborn stains which will not come out in clean tap water. If
soaps or detergents are used, be sure to rinse the test tubes several times before
allowing them to dry.
E. Avoid storing the equipment where it will be exposed to extreme heat or cold.
Do not leave the reagents exposed to direct sunlight for a prolonged period of
time. Store the equipment and reagents out of the reach of very young children.
NOTES TO THE TEACHER
The materials and manual in this kit are provided as the tools needed to conduct
many important investigations. It is hoped the students’ and teachers’ interest will
not be limited to the experiments or procedures as they are outlined in this manual.
They provide the basic information needed to conduct many fascinating
investigations and activities. A number of suggested activities are provided in the
form of additional, open-ended experiments. They should spur the student’s
imagination to investigate other problems which are related to the subject. The
inquiring student may devise other experiments using the materials provided in this
unit or they may make modifications to the methods and incorporate additional
materials and test kits.
12
NI TRO GEN OX IDES (NO
x
)
Internal combustion engines in automobiles, trucks, and other vehicles produce
gaseous nitrogen oxides (NO
x
) because nitrogen and oxygen from the air combine
during combustion. Lightning during thunderstorms also forms nitric oxides by the
direct union of nitrogen and oxygen in the air.
Sulfur dioxide and nitrogen oxides dissolve in atmospheric moisture to form nitric
acid and sulfuric acid. Nitric acid and sulfuric acid are strong acids. They dissociate
completely as carbonic acid in rain water to form hydrogen ions, making the pH of
rain water more acidic.
HNO
3
nitric
acid
+
H
2
O
rain
=>
NO
3
-
Nitrate
ion
+
H +
hydrogen
ion
+
H
2
O
rain
H
2
SO
4
sulfuric
acid
+
H
2
O
rain
=>
HSO
4
-
hydrogen
sulfate
+
H +
hydrogen
ion
+
H
2
O
rain
5