Question

You vacate the laboratory after dropping a 1 Liter bottle of Acetone. The bottle breaks and all of the acetone evaporates. The ventilation is turned off due to the warm spell. The lab measures 30 feet x 25 feet x 10 feet. Molecular weight is 58, density of the liquid is 0.792 grams per milliliter, TLV (Threshold Limit Value) is 750 ppm.

What is the concentration of acetone vapors in the room?

You turn of the ventilation.There is one register measuring 1 foot x 3 feet. The average outlet air velocity is 40 feet per minute. You will let people back into the lab when the concentration is down to the TLV (750 ppm). How long must they weight to return?

Answer 1

The number of moles of Ac spilled are:

Since 1 mol of any vapor at room temperature occupies 24.45 l:

And given that 1 ft3 = 28.32L:

The volume of air on the other hand is equal to:

Then the concentration of contaminant is:

The volume of air required to down the concentration to 750 ppm is equal to:

The volumetric air flow rate is given by:

Then the time required to dilute the atmosphere is: