MUTLTIPLE CHOICE QUESTION:If you wanted to make 50 mL of 35 mM NaCl solution by diluting a 3.5 M stock solution of NaCL, how many microlitres of the stock solution would you use?
a) 10 b)500 c)5000 d)100 e) 5

Question

MUTLTIPLE CHOICE QUESTION:If you wanted to make 50 mL of 35 mM NaCl solution by diluting a 3.5 M stock solution of NaCL, how many microlitres of the stock solution would you use?
a) 10 b)500 c)5000 d)100 e) 5

anonymous · Answer

You're probably better off sending this over to the Chem section, but I'll give it my best shot (no guarantees though haha).

Right, so the logic of a dilution problem is pretty simple - you want to take enough of your stock solution so you have your desired amount of moles, and then you simply want to add some more water to get to your desired amount rigt?

So your first step would be to find the # of moles you want (namely, the amount in 50 mL of 35 mM NaCl). Can you do that part?

anonymous · Answer

yeah i got 1.75 x 10^-3 moles

anonymous · Answer

Awesome. So you want the corresponding amount (in liters) of your stock solution that yields that many moles. One more unit conversion step and you're there - what do you end up with?

anonymous · Answer

u need microlitres

anonymous · Answer

i got 500 though lol what did u get?

anonymous · Answer

Yeah same here; sorry for the delay

anonymous · Answer

awsome man are u a bio major?

anonymous · Answer

B