5. The LC50 for fluorine is 0.29 mg/m3. What is this in ppm at 25 oC and 1 atm pressure? How does this compare to the PEL?
To convert from mg/m³ to parts per million (ppm), we need to know the molecular weight of the substance. The molecular weight of fluorine is 18.998 g/mol.
1. First, convert the mg/m³ value to g/m³:
0.29 mg/m³ = 0.00029 g/m³
2. Convert g/m³ to mol/m³:
To do this, divide the mass in g by the molecular weight in g/mol.
0.00029 g/m³ / 18.998 g/mol ≈ 1.53e-5 mol/m³
3. Convert mol/m³ to ppm:
Since 1 ppm is equivalent to 1 part per million divided by the total number of parts, we can use the formula:
ppm = (mol/m³ * 10^6) / (pressure in atm * RT)
where R is the ideal gas constant (0.0821 L*atm/(mol*K)), and T is the temperature in Kelvin.
Let's convert 25 oC to Kelvin:
T = 25 + 273.15 = 298.15 K
Now we can calculate the ppm value:
ppm = (1.53e-5 mol/m³ * 10^6) / (1 atm * 0.0821 L*atm/(mol*K) * 298.15 K)
≈ 0.574 ppm
So, the LC50 for fluorine is approximately 0.574 ppm at 25 oC and 1 atm pressure.
Now, how does this compare to the PEL (Permissible Exposure Limit)?
To make a comparison, we need to know the PEL for fluorine. The PEL represents the maximum allowable exposure to a substance over a given time period. Please provide the PEL for fluorine, and I will be able to make a comparison.