Question

The National Institute for Occupational Safety and Health (NIOSH) sets standards for CCl4 in air at 12.6 mg/m^3 of air (a time average over 40 hr). The CCl4 found in a sample is 4800 ppb. Does the sample meet the NIOSH standard?

Answer 1

Answer:

Sample is greater than the standard (32.96 mg/m³ > 12.6 mg/m³)

Explanation:

Please look at the solution in the attached Word file

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Answer 2

Answer:

No, it doesn't.

Explanation:

To convert ppb to mg/m³ we first need to convert to ppm, by just divide the amount by 1,000, so the concentration in the sample is 4.8 ppm.

mg/m³ = (ppm x molar mass)/molar volume

Using the molar mass in gram and the molar volume in liters, multiplying by the parts per million, we will get the concentration in mg/m³.

Molar mass of C = 12 g/mol; molar mass of Cl = 35.5 g/mol

Molar mass of CCl4 = 12 + 4x35.5 = 154 g/mol

Assuming, 25ºC and 1 atm, the molar volume of an ideal gas is 24.45 L, so:

mg/m³ = (4.8 x 154)/24.45

mg/m³ = 30.2

Which is higher than the limit of 12.6 mg/m³