Hi,
I need help with this problem--- I have no idea how to go about it
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An average adult breathes about 8.5 x 10^3 L of air per day. The concentration of lead in higly polluted urban air is 7.0 x 10^-6 g of lead per one m3 of air. Assume that 75% of the lead is present as particles less than 1.0 x 10^-6 m in diameter, and that 50% of the particles below that size are retained in the lungs. Calculate the mass of lead absorbed in this manner in one year by an average adult living in this environment.
***Note answer has two sigfigs
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Thanks for all the help you guys can provide,
manny
How about this hint.
(7.0 x 10^6 g/m3) x 0.75 x 1/2 = amount of consumable lead. Convert 8.5 x 103 L to cubic meters (or the other way around--it doesn't matter which one you convert) and calculate the amount consumed per day. Then multiply by 365 to convert to amount per year.
ok! thanks... Dr. Bob your the best!!!
I assumed you meant (7.0 x 10^-6 g/m3)
I got 8.1 x 10^-3 g Pb / year
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got a 0.
To calculate the mass of lead absorbed by an average adult living in this environment, we need to consider the volume of air breathed, the concentration of lead in the air, and the percentage of lead absorbed into the lungs.
First, let's calculate the volume of air breathed in one year. We are given that an average adult breathes about 8.5 x 10^3 L of air per day. To find the annual volume, we multiply this by the number of days in a year:
Annual volume = 8.5 x 10^3 L/day * 365 days/year
Next, let's calculate the concentration of lead in the air. We are told that the concentration is 7.0 x 10^-6 g of lead per 1 m^3 of air.
Now, let's consider the percentage of lead that is present as particles less than 1.0 x 10^-6 m in diameter and the percentage of particles below that size that are retained in the lungs. We are given that 75% of the lead is in particles smaller than 1.0 x 10^-6 m in diameter, and 50% of the particles below that size are retained in the lungs.
To calculate the mass of lead absorbed in one year, we can use the following formula:
Mass of lead absorbed = (Annual volume * Concentration * Percentage of lead particles * Percentage retained in lungs)
Substituting the given values into the formula, we have:
Mass of lead absorbed = (Annual volume) * (Concentration) * (0.75) * (0.50)
Simply multiply the values and round the answer to two significant figures to get the final result.