A laboratory experiment requires 2.25 L of a 1.0 M solution of phosphoric acid (H3PO4), but the only available H3PO4 is a 9.0 M stock solution. How could you prepare the solution needed for the lab experiment?

Question

btaylor · Answer

Well, use the formula (M1)(V1)=(M2)(V2). You know the required molarity and volume (M1 and V1, respectively), and the initial molarity (M1). You are solving for V1, the volume of the stock solution that you dilute to 2.25 L. V1=(M2)(V2)/(M1), so V1=(1.0)(2.25)/(9.0). By this, V1=0.25 L. So you take 0.25 L of stock solution, add it to 2.00 L of distilled water, and you get your 2.25 L of 1.0 M solution.

anonymous · Answer

Are you a science teacher or something? haha

btaylor · Answer

No, I just love and understand chem. I don't know why.

anonymous · Answer

Dang, lucky! Are you in high school?

btaylor · Answer

Yes.

anonymous · Answer

What grade?

btaylor · Answer

Just finishing my sophomore year.

anonymous · Answer

Me too! haha 
I'm in virtual school.