Question

Given:

At normal temperature and pressure, the following conversion formulas may be used to convert back and forth between ppm and mg/m3 . mg/m3= [(MW x ppm) / 24.45] or ppm = [(24.45 x mg/m3 ) / MW] MW: molecular weight in g/mole In these equations 24.45 is the volume (in liters) of a mole (gram molecular weight) of a gas or vapor when the pressure is at 1 atmosphere (760 mmHg) and the temperature is at 25°C. When temperature and pressure are not both 760 mmHg and 25°C (normal temperature and pressure, NTP) you must consider the effect of temperature and pressure on molar volume. In these cases the following formulas may be used:

mg/m3 = [(P x MW x ppm) / (62.4 x T)] ppm = [(62.4 x T x mg/m3) / (P x MW)]

MW: molecular weight in g/mole 62.4: universal gas constant

T: temperature in Kelvin (add 273 to the temperature in Celsius to convert to Kelvin)

P: pressure in mmHg

Question:

You need to calibrate a direct-reading benzene meter, and you need to create a test atmosphere of 0.5 ppm. How much liquid benzene needs to be released? Assume the room to be the same size as in problem #3, there is complete mixing and no ventilation, and the atmospheric conditions are 760mm Hg, 20 degrees C. The size of the room is 32 ft x 22 ft x 8 ft.

Answer 1

Conveneked Concent atron 62. 4 XT 62.4X293 Room volwre 59. 63 w3. ben2ore to be