Chemistry Problem?

Question

You have 2 vials, one with Ammonia & the other with Chlorine. When they are opened across the room, which would you expect to smell first and why?

Answer 1

NH3 has a mass of 17 while Cl2 has a mass of 71. The gas with the lower mass will diffuse faster, so NH3 will be the one to smell first.

Answer 2

Whichever compound can diffuse faster is the one that will reach your nose first. This equation relates the diffusion of two different molecules/compounds/etc:

diffusion rate of A / diffusion rate of B = sqrt(Mb/Ma)

Ma is the molar mass for compound A, and Mb is the molar mass for compound b. The molar mass for ammonia gas, NH3, is 17. For chlorine gas (Cl2) it is 70.9. So if you use the formula, pretending ammonia gas is A and chlorine is B, you get this relative rate: sqrt (70.9/17) = 2.04222. This means ammonia diffuses 2.04222 times as fast as chlorine does.

Of course, you can forego the equation altogether and just think that the lighter gas will generally travel faster if both are under the same conditions.

Answer 3

Assuming that they are equidistant from your nose, you would smell the ammonia first. NH3 = MM = 17 . Cl2 MM = 70.9

Using Grahams law of diffusion RateNH3/RateCl2 = sqrt (70.9)/sqrt (17)= 2.04. The rate of diffusion of ammonia is a little over 2 x faster than ther rate of diffusion of chlorine gas.

Graham's law = Rate of diffusion gas A Vs rate of diffusion of gas B is inversely proportional to the square roots of their molar masses.

Answer 4

You'd smell the ammonia first because its molecules are lighter and diffuse faster than chlorine.