## cooltowl one year ago You dissolve the sample of FD&C Red 40 (molar mass 496.4200 g/mol) in enough water to make 250.0 mL of solution. We call this the stock solution. What is the concentration of the stock solution in terms of molarity?

1. anonymous

$Molarity=\frac{ mol solute }{ volume }$ mol solute in grams volume in liters.

2. anonymous

Molarity in M

3. cooltowl

so I divide the molar mass or Red 40 by 250 ml?

4. anonymous

FD&C Red 40 is the name of substance being dissolved. 1 sample of it would have 496.420g

5. cooltowl

how do I get moles of solute?

6. cooltowl

Never mind I got it the answer. I divided 1.833x10^-5/.25

7. anonymous

Oh, I think you didnt post more information with this question. This is part of a series of questions right?

8. cooltowl

Yeah Im sorry about that I just realized it when I was trying to solve the problem but thank you. you helped a lot

9. anonymous

No wonder. Just post information that goes with the question next time. Good luck.

10. Jhannybean

Yeah, seems like some parts were missing.