For the following calculations, assume a classroom with dimensions 6m by 10m by
ID: 1022 • Letter: F
Question
For the following calculations, assume a classroom with dimensions 6m by 10m by 3m.
A) You have a one liter flask containing, at room temperature and pressure, a harmless gas not normally found in air such as sulfur hexafluoride (SF6). If the gas in the flask is released and mixed thoroughly throughout the classroom, what is the final concentration of the gas in parts per million by volume?
B) Based on the fractions by volume in dry air, express the equivalent pure volumes of pure carbon dioxide, krypton, carbon monoxide, and chlorofluorocarbons found in the classroom, using common units such a liters, cubic centimeters, or others as appropriate.
Explanation / Answer
A)
6x10x3 room = 180 m3 1 cm3=1 mL
So 180 m3= 1.8 * 105 L (This is the total volume of the room)
1 L / 1.8 * 105 L = 5.6 * 10-6 or 5.6 ppm
B)
CO2= 383 ppm normally.
x / 1.8 * 105 L = .000383
x = 68.94 L CO2
Kr=1 ppm normally.
x / 1.8 * 105 L = .000001
x=0.18 L Kr
CO=0.07 ppm normally
x / 1.8 * 105 L = .00000007
x= 0.0126 L CO
CFC's = ~ 10-10 ppm
x / 1.8 * 105 L = 10-16
x=1.8 * 10-11 L CFC's
Literary information (including ppm values of air) : http://www.sundogpublishing.com/AtmosThermo/Resources/AtmosThermoCh1-2.pdf