[katsumi]

I am new here so please forgive me if this is in the wrong section.
I am getting ready for a Chemistry test and there are two questions that I I want to make sure I know.  I've been out of college for 7 years and I mostly work in a Microbiology lab.

OK.

1. 3ml of blood containting phenobarbitol at a concentration of 1ml/L was extracted with an organic solvent.  The Solvent was seperated from the aqueous phase and evaporated to dryness.

The residue was dissolved in 30 microliters of methanol.

What weight of penobarbitol would one microliter of the methanol solution contain?

Please work it out complete with conversions.  I want to know the in and outs in solving this question.



2.  You need to make a 15% sulfuric acid solution in water. The recipe calls for 15 ml of acid to make 100 ml of solution. Describe in detail how you would prepare this solution.

Be sure to include type of glassware used, the order of events and any safety considerations.

*now I thought you would meausure out 15ml of H2SO4 and add it to 85ml of water.  This gives you a 100ml Solution.  Am I incorrect?*

Thank you so much! 

[Sam (NG)]

Ok, I'll bite, but I'm not working it all out for you, it's not the spirit of these forums:

1) I'm assuming that you meant 1mg/ml considering that phenobarbital is a solid. So, using this, calculate the amount of phenobarbital in 1 ml of blood, then 3 ml of blood.  Assuming perfect extraction (we wish), then this is the amount of phenobarbital in the 30 microlitre methanol solution. (I'm sure that you can figure the rest out).

2) Assuming that you want to make a solution with  a volumetric 15 % sulfuric acid (15 % v/v) then you are correct.  However, it asks specifically what glassware you would use. Are you familiar with making volumetric solutions?  Why did you decide to add the 15 ml conc sulfuric to the water?