Question

1. The LD₅₀ of cocaine is 95.1 mg/kg. Calculate the concentration of a solution, in molarity if they drank 1 liter of it.

100 g / 303.346 g/mol = 0.329 mol of cocaine.

0.329 mol/ 1 L= 0.329 M for molarity.  

Is this correct?

2. Find one other concentration unit [mass/mass (g/g) or mass/volume (g/ml) percentage, ppm or ppb] that would be toxic to a 85 kg person. Assume the density of a solution of your substance is the same as that of water. 1 mg/mL.

If 95.1 mg/kg is the LD₅₀ of cocaine, then for an 85 kg person, is lethal. This concentration in ppm, $5vytCsvVfFwAAAABJRU5ErkJggg==$ . I feel like I am missing something here? What do I do with the density part?

Answer 1

For 100 gm this is correct

but for 85 kg per person

mass of solute =(95.1$\times$85)mg=(95.1$\times$85$\times$10-3)gm=8.08gm

moles=8.08$\div$303.346=0.02664mol.=0.03mol.

volume of solution=1litre=1000ml

density of solution=1gm/ml

mass of solution=1000gm

1.MOLARITY= moles$\div$volume of solution in litre=0.03$\div$1=0.03M

2. %(mass$\div$mass)=(mass of solute$\div$mass of solution)$\times$100=(8.08$\times$100)$\div$1000=0.8

%(mass$\div$volume)=(mass of solute$\div$volume of solution)$\times$100=(8.08$\times$100)$\div$1000=0.8

ppm=(mass of solute$\div$mass of solution)$\times$106= (8.08$\times$106)$\div$1000=8080ppm.(approx)