Experimental Background
Ammonium nitrate is a chemical that is widely used by gardeners as a fertilizer. It
is a white powdery substance that can be very dangerous if not handled correctly. It is not
usually found in a crystallized state unless it is being used for an experiment. Because it
is used in creating explosive agents, it is classified as an oxidizing agent (Workplace
Health and Safety Queensland.) An oxidizing agent is an agent that gives away its
oxygen element(s) to another element creating a chemically bonded compound.
This chemical is used in explosives because of its chemical properties. It has a
boiling point of 210 degree Celsius and a melting point of 170 degrees Celsius. The
boiling point is when the chemical becomes dangerous in its use. As it heats up, it starts
to expand rapidly and soon explodes. It has a pH of 4.0 making it acidic and flammable
(Ammonium.)
One of the biggest issues with Ammonium nitrate is its use in Afghanistan as an
explosive. In the form of fertilizer, the chemical is used to create bombs that have led to
the death hundreds of US troops in Afghanistan. Due to this, troops have started trading
farmers for their Ammonium nitrate fertilizer in return for money (Pike.) Terrorists in
other areas of the world have also made explosives with ammonium nitrate. It reacts with
fuels in a fast manner causing the gas to heat up and explode. Many bombs have been
made with this knowledge (Nanjappa.) It is also not a banned substance due to its wide
variety of use, even though the government has tried to make it illegal using the
Explosives Substance Act (Economic Times.)
In past experiments, ammonium nitrate has been used to create small reactions
that cause instant flames or freezing. In one experiment, a certain amount of water is
added to a beaker. Then the temperature of the water is recorded and ammonium nitrate is
added. The purpose of the experiment is to see the affect of the ammonium nitrate on the
temperature of the water. This experiment is an example of an endothermic reaction
because the temperature of the water decreases significantly (United Nuclear.) Because
ammonium nitrate is highly reactive, it can be used with ammonium chloride and Zinc
dust to create a flame. This mixture can be extremely flammable if it is in any contact
with water (United Nuclear.)
The purpose of this experiment is to observe the affect of the change in
temperature of a water and ammonium nitrate mixture when the amount of ammonium
nitrate is dissolved. To carry out this experiment, 30g of ammonium nitrate, 1g distilled
water, 10 beakers of 100ml, and a thermometer will be used. In 10 beakers, there will be
75ml of distilled water. The temperature of the water in each beaker will be taken and
recorded. After this, a fixed amount of ammonium nitrate will be dissolved into each
beaker of water. After the ammonium nitrate is completely dissolved, the temperature of
the water will be taken and recorded again for each mixture. This process will be repeated
with different amounts of ammonium nitrate being dissolved into the water. The results
of the temperature changes will be observed, recorded, and then analyzed.
Experimental Results
After three trials were done for each amount of Ammonium nitrate mixed with
water, the results of the temperatures were averaged into bar graphs. The graph below
shows the first few trials of three grams averaged into final results.
Affect of Ammonium Nitrate on
Temperature of Water
Temperature in Degrees
Celsius
25
20
15
Series1
Series2
10
5
0
1
2
3
Grams of Ammonium Nitrate (3)
Figure 1
In the first part of the experiment, the 175ml of water was an average of 23.3 degrees
Celsius before the Ammonium nitrate was added. After the compound was added, the
temperature dropped an average of 1.3 degrees Celsius as seen in Figure 1.
After the changes of the three grams of Ammonium nitrate were tested, four
grams of Ammonium nitrate were prepared to be mixed into the water. The results of
these trials are shown in Figure 2. In these trials, the average temperature of water was
21.5 degrees Celsius. The graph shows the drop in temperature after the compound was
added. The average drop in temperature was 1.5 degrees Celsius.
The next amount of Ammonium nitrate added was five grams. Once all of the
Ammonium nitrate was measured out and everything was set up, the temperature of the
water was recorded. The results are shown in Figure 3. The average temperature of the
water in these trials was 21.6 degrees Celsius. The average drop in temperature after the
Ammonium nitrate was dissolved into the water was 2.2 degrees Celsius.
Discussion
Once the graphs were created, the results showed that the Ammonium nitrate did
drop the temperature of the water as predicted. It was a slight change that occurred in
every trial. As the amount of the compound increased, the drop in temperature increased
as well. Some days, the starting temperature of the water was lower than the starting
temperature of other days. This factor was ruled out in the averaging of the change in
temperature from before and after. This showed that the more grams of the compound are
added, the greater affect it will have on the final temperature of the water.