[rupalini]

If you were asked to prepare 500 mL of a 100 M stock solution of drug Y (molecular
weight 180), calculate how many milligrams of drug Y you
would need to weigh out in order to make this solution. SHOW YOUR
CALCULATIONS.

Can anyone help on the above question??
I'm really stuck and need help as I have a resit coming up
thanksxxx

[pure_joy]

100 M stock solution

100M? or should it be milimoles? Because a 100M solution is quite uncommon

[rupalini]

ooops, it shud be 100micromolar
can u help? its driving me mad!

[rupalini]

anyone?

[Cetomacrogol]

9 mg

[pure_joy]

(Original post by Cetomacrogol)
9 mg

calculations:

M= 180 g/mol
V=500ml= 0,5 dm~3
c= 0,0001 M/ dm~3

quantity (in moles) of drug Y in 0,5 dm3 of the solution:

x= 0,0001 mol * 0,5 dm~3
------------------------
1dm~3

x= 0,00005 mol

mass of drug Y in o,5 dm~3 of the solution:

m= 0,00005 mol * 180g/mol = 0,009g= 9mg