Answer:
Option b)
Explanation:
To do this, we know that we have the permissible exposure level of 0.75 ppm, or we can write it as 0.75 mg/kg.
Now, with the quantity of breath air of 6 L, we need to know how much of formaldehyde can be in there. Let's convert the volume of air to mass.
The density of the air is 1.2 kg/m³ or 1.2x10⁻³ kg/L so:
m = 1.2x10⁻³ * 6 = 7.2x10⁻³ kg
Now with this mass, let's see how much formaldehyde is permited in this mass:
mass of formaldehyde = 7.2x10⁻³ kg * 0.75 mg/kg
mass = 0.0054 mg
But the answer is expressed in grams, so let's convert the miligrams to grams:
mass = 0.0054 mg * 1 g/1000 mg = 5.4x10⁻⁶ g
This is the mass and correct answer
