Question

Humans breathe about 500 ml of air per breath and take about 12 breaths per minute during
normal activities. If a person is exposed to an atmosphere containing benzene at a concentration
of 10 ppm (by volume), how many grams of benzene will be deposited in the lungs during an 8-
hour shift if all the benzene that enters remains in the lungs? How many drops of liquid is that?
A drop of liquid contains about 0.05 cm3
. The specific gravity of benzene is 0.879. If you were
the worker, would this be acceptable?

Answer 1

Answer:

mass of benzene in the lungs = 28.8 g of benzene

Explanation:

Volume of air breathed per hour = 500 mL * 12 * 60 = 360000 ml = 360 Litres of air

In 8 hours, volume of breathed air = 360 L * 8 = 2880 Litres of air

Concentration of benzene in air = 10 ppm

Note:  1 ppm = 1 mg per liter (mg/L)

10 ppm = 10 mg/L

Therefore, mass of benzene in the lungs in an 8-hour shift = 10 mg/L * 2880 L

mass of benzene in the lungs = 28800 mg

Converting to grams = 28800/1000

mass of benzene in the lungs = 28.8 g of benzene