# Homework Help: The Answer is Yes , but I need to show HOW. Plz Help.

1. Sep 6, 2011

### knottlena

The Answer is "Yes", but I need to show HOW. Plz Help.

1. The problem statement, all variables and given/known data
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.)

2. Relevant equations
PV=nRT & LxWxH

3. 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.

2. Sep 6, 2011

### SteamKing

Staff Emeritus
Re: The Answer is "Yes", but I need to show HOW. Plz Help.

You have not said how much mercury is spilled.

3. Sep 6, 2011

### knottlena

Re: The Answer is "Yes", but I need to show HOW. Plz Help.

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 :)

4. Sep 6, 2011

### diazona

Re: The Answer is "Yes", but I need to show HOW. Plz Help.

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?

5. Sep 6, 2011

### SteamKing

Staff Emeritus
Re: The Answer is "Yes", but I need to show HOW. Plz Help.

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

6. Sep 9, 2011

### knottlena

Re: The Answer is "Yes", but I need to show HOW. Plz Help.

Thank you