[Georgios84]

I have really tried to do these questions but just can't. Perhaps someone can help me?

The questions are:

1. A 70kg man swallows a 1.00g chunk of NaCN (sodium cyanide), which fell from an overhead beam into a sandwich he was eating. Immediately the soluble cyanide reacted quantitatively with the HCl in his gastric juices to form HCN gas (hydrogen cyanide).

NaCN (aq) + HCl (aq) à HCN (g) + NaCl (aq)

This caused him to belch 400mL of gas, containing 2800ppm of HCN.
What mass of NaCN is equivalent to the amount of cyanide remaining in his stomach after belching?
Assume that the belched gas is completely expelled from his body.
The minimum lethal dose (LDL0 ) for man is 2.857mg NaCN/kg. Is the patient in danger? Would you administer CPR?

2. A weevil returns to its nest from the fields with 600ng of pesticide of molecular weight 378 on each foot (It has 6 feet). The insect dies from acute cholinesterase poisoning. The subterranean nest – which has no ventilation – has a volume of 11.0cm3 . The pesticide evaporates from the 6 feet of the unfortunate weevil.

Calculate the concentration of pesticide in the nest after evaporation. The short term exposure limit for adult weevils is 1ppm. Are the other weevils in the nest in danger?
[Hints: - To interpret ppm (parts per million), calculate the (partial) pressure of pesticide in the nest and remember Avogadro’s law. A weevil is an insect, and you may assume that it has not lost any feet. You may take the temperature of the nest to be 290 K]

The equations we were given to help were
Avogadro constant NA = 6.022 x 1023 mol-1 ; Gas constant R = 8.314 J K-1 mol-1 = 0.08205 L atm K-1 mol-1 , 1 bar = 105 Pa, 1 atm = 101325 Pa.

Many thanks for your time.

[Borek]

Tedious, but not very difficult. Show us what you did.