Lori Raulston
CHEM 1010
Roylance
Signature Project
Case Study: Deducing composition of Inhaled Substance
On July 4, 2015, I attended a family barbecue, where my brother- and father-in-law were
setting off aerial fireworks. I was sitting away from the street (where they ignited the aerials,)
close to the house. It was dark. Dark enough that I didn’t see the falling ball of ash until just
before it hit me in the eye (it scratched my glasses, but they saved my eye, according to my
doctor.) I was rushed into the house, and my eye immediately flushed. My mouth and throat
were burned, and are still sensitive. For my project, I want to find out what was in the ash, and
how much of it (not subtracting what would have fallen off in flight.)
I knew the star (the small part inside the rocket that caused the individual burst,) had been
green, and the remnants extremely ashy. My in-laws were able to tell me only that it had come
from a homemade rocket. Unfortunately, the creator had already left, so I would have to
research the mix myself.
I went through recipes online until I found one that described the result as “very ashy.” It
was titled, “Green #3,” and dictated the following the ingredients:
1. Barium nitrate
2. Magnesium powder
3. Parlon
The formulas are: Ba(NO3)2 , Mg, and C4H6Cl2, respectively. I recognized the elements
of a combustion reaction: a carbon-hydrogen compound and a source of oxygen. The net
equation would then be: Ba(NO3)2(s) + C4H6Cl2(s) → CO2(g) + H2O(g). That would leave
Ba(NO2)2 (as the oxidizer, the barium nitrate released one third of its oxygen to become barium
nitrite) and the Mg+2 cation to join with the Cl2-2 anion to form MgCl2 (magnesium chloride.)
The carbon dioxide and water would be released in the explosion as gasses, leaving the solids
barium nitrite and magnesium chloride. Barium nitrite is a salt health-coded as “harmful by
inhalation,” and “irritating to the respiratory system.” Magnesium chloride is also a salt, and,
when inhaled, causes “eye and respiratory tract irritation.” It seemed like I was on the right
track, so I moved forward to find the amounts that had been created in the reaction.
I read with the recipe that 500g was a typical batch size when creating a Green #3 star.
The exact recipe would be illegal to post, and only estimates were given, so I would have to find
the amounts myself.
First, I balanced the equation:
11Ba(NO3)2 + 2Mg + 2C4H6Cl2→11Ba(NO2)2 + 2MgCl2 +8CO2 + 6H2O
I then calculated the gram formula masses of each reactant compound:
Ba(NO3)2:
Ba:137.34x11=1510.74
N:14.01x2=28.02
O:15.99x6=95.94
Total=1634.7g/mol
Mg:
Mg:24.31x1=24.31
Total:24.31g/mol
C4H6Cl2:
C:12.01x4=48.04
H:1.008x6=6.05
Cl:35.45x2=70.9
Total=124.99g/mol
The total gram formula mass of all reactants is 1784g/mol. To find the percent
composition of each compound, I divided the molar mass of each by the total molar mass of the
compound, and multiplied the quotient by 100.
Percent composition of Ba(NO3)2 =
Percent composition of Mg =
1634.7g/mol
1784g/mol
24.31g/mol
1784g/mol
= 91.63%
= 1.36%
Percent composition of C4H6Cl2 =
124.99g/mol
1784g/mol
= 7.01%
91.63% of the 500g sample is 458.15g of Ba(NO3)2.
1𝑚𝑜𝑙
Converting that to moles makes it: 458.15g(1634.7𝑔) = .28 mol Ba(NO3)2
From that number, I used the balanced equation to compare amounts of products.
11 mol Ba(NO2)2
.28 mol Ba(NO3)2 x (11 mol Ba(NO3)2 ) = .28 mol Ba(NO2)2
229.32g
.28 mol Ba(NO2)2 x (
1mol
) = 64.21g Ba(NO2)2
2 mol MgCl2
.28 mol Ba(NO3)2 x (11 mol Ba(NO3)2 ) = .05 mol MgCl2
95.21g
.05 mol MgCl2 x ( 1mol ) = 4.76g MgCl2
My eye feels like nothing happened. My mouth and throat are still a little raw. At least
now I know what was in that ash and how much of it. (I am concerned that it involved
researching illicit materials and formulas to find out.)
Works Cited
"Barium Nitrite, Ba(NO2)2." Barium Nitrite, Ba(NO2)2. N.p., n.d. Web. 02 Aug. 2015.
DeCoste, Donald J. "8: Chemical Composition, 9: Chemical Quantities." Introductory
Chemistry. By Steven S. Zumdahl. 8th ed. Mason: Cengage Learning, 2014. 162+. Print.
Custom Edition for Salt Lake Community College.
Gondhia, Reema. "Composition." The Chemistry of Fireworks. Imperial College London, n.d.
Web. 02 Aug. 2015.
"Percentage Composition and Empirical Formulas." The Internet Science Room. Ed. Jim Askew.
21st Century Education, n.d. Web. 02 Aug. 2015.
"Pyrotechnic Formulas: Stars." - CannonFuse.com. N.p., n.d. Web. 02 Aug. 2015.