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**Concentrations and Molarity??**

## Homework Statement

This problem was given in class; the teacher left it to us to solve it on our own. He wrote this problem himself:

you have 150 millimolar of Trypan Blue. you need to get 13.3 millimolar Trypan Blue in a 30% ethanol solution in EXACTLY 10 milliliters. How do you do it?

## Homework Equations

## The Attempt at a Solution

at first, i thought it was a simple solution. I thought that because you need a 30% solution in 10 milliliters, that means that you need 3 mL of Ethanol, right? Then I thought that the other 7 mL would be Trypan Blue. I determined the formula weight of Trypan to be 960.81. But I don't know how much Trypan is needed in correlation to the Ethanol. Is this right? Is there a better way of doing this problem??

Thank you! This problem has been bothering me.