Calculate the amount of HCN that gives the lethal dose in a small laboratory room measuring 12.0 ft*15.0 ft*8.60ft.

Given:

Dimensions of the room = 12 ft * 15 ft * 8.60 ft

To determine:

The amount of HCN that gives the lethal dose in the room with the given dimensions

Explanation:

As per the World Health Organization, the lethal dose of HCN is around 300 ppm

300 ppm = 300 mg of HCN / kg of inhaled air

Volume of air = volume of room = 12 * 15 * 8.6 = 1548 ft³

Now, 1 ft³ = 28316.8 cm³

Therefore, the calculated volume of air corresponds to:

1548 * 28316.8 = 4.383 * 10⁷ cm3

Density of air (at room temperature 25 C) = 0.00118 g/cm3

Thus mass of air corresponding to the calculated volume is

Mass = Density * volume = 0.00118 g/cm3 * 4.383 * 10⁷ cm3

= 5.172*10⁴ g = 51.72 kg

Lethal amount of HCN corresponding to 51.72 kg of air would be.

= 51.72 kg air * 300 mg of HCN/1 kg air = 15516 mg

Ans: Lethal dose of HCN = 15.5 g