[eltornado90]

Hello,

Okay so I have this problem in chemistry and I'm seriously lost :


An aqueous solution of 0.5% by mass is used (ex.
0.5 g / 100 g H 2 O) TFA, trifluoroacetic acid, MM = 114.02 g / mol). TFA is a pure liquid at ambient temperature with a density of 1.489 g / mL while the 0.5% aqueous solution will have a density of 1.00 g / mL.

a) What volume of pure TFA is needed to prepare 1.00 L of 0.5% TFA?

For this part I was thinking of using the dilution equation C1V1=C2V2 and find the concentration maybe through the density of the 2 forms of TFA but it doesn't work.

b) What is the molar concentration of this TFA solution?

Thank you !

[Borek]

No, it is not about dilution.

Assuming TFA was a solid, how would you start?

[eltornado90]

Well, I could find the mass of TFA using the second density I think.

[Borek]

You are on the right track.

Now, you have TFA mass, you have its density. Rings a bell?