Does Spilled Mercury Exceed EPA Air Quality Limits in the Lab?

  • Thread starter Thread starter knottlena
  • Start date Start date
Click For Summary
The discussion centers on calculating whether the concentration of mercury vapor in a laboratory exceeds the EPA air quality limit of 0.050 mg Hg/m3 after a thermometer spill. The researcher has provided the dimensions of the lab and the vapor pressure of mercury at 20 degrees Celsius but is struggling to complete the calculations. Key equations mentioned include the ideal gas law (PV=nRT) and the volume of the lab. Other participants suggest reevaluating the calculations and considering the necessary quantities to determine the density of mercury vapor. The consensus indicates that the concentration likely exceeds the limit, but the exact calculation steps are unclear to the original poster.
knottlena
Messages
6
Reaction score
0
The Answer is "Yes", but I need to show HOW. Plz Help.

Homework Statement


A researcher breaks a thermometer & spills most of the mercury in it on the floor of a laboratory that measures 15.2 m Long, 6.6 m Wide, & 2.4 m High. Does the concetration of mercury exceed the EPA air quality regulation of .050 mg Hg/m3 of air? (Temp of the rm is 20 degrees celcius; the vapor pressure of mercury at this temp is 1.7 x 10 to -6th atm.)


Homework Equations


PV=nRT & LxWxH


The Attempt at a Solution


LxWxH=240.77 m3 x 100 to the 3rd power=2.4x10 to the 8th cm3 x 1mL/1cm3=2.4x10 to the 8th/1000 L = 2.4 x 10 to the 5th L
Hg = 200.59g/mol
n=PV/RT (1.7 x10 to -6th)(2.4 x 10 to the 5th)/ (.0821 Latm/mol K) (293K) = 1.4 x 10 to the 3rd mol

I just don't know where to go from here. I know the answer is 14.1 mg/m3, but I can't figure out how the teacher got there. HELP PLEase. Thank you in advance.
 
Physics news on Phys.org


You have not said how much mercury is spilled.
 


My professor did not offer up that information in the question. A couple other students in my class were able to solve it with the information given, but I am at a loss. I appreciate you trying :)
 


Think about it backwards. You need to wind up with a density of mercury vapor. What quantities do you need in order to calculate that density?
 


Check your calculation for n. I think your answer shown is much too large.
 


Thank you
 

Thread 'Magnitude of buoyant force in fluids of different densities'

The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?
View full post »

Similar threads

How Does Radon-222 Impact Indoor Air Quality?
  • · Replies 1 ·
Replies
1
Views
4K
Find Hg Vapor Mass in Grams at 20C Room
  • · Replies 3 ·
Replies
3
Views
2K