[student12345]

A known mass of a diprotic or triprotic acid is dissolved in water to make a precise solution. Samples of this solution are titrated with a standard solution of NaOH. The data generated is used to determine the molar mass of the acid.

I understand titration, however I am unclear as to how I know how much mass is dissolved in each sample I am titrating. I need the mass in order to solve for molar mass, but I only know the initial mass of the solid, and not the mass dissolved in each separate sample used in the titration.  Thanks!

[Borek]

Are you given volume of the solution and volumes of the titrated samples?

[student12345]

Since I am making the original solution, I am pretty sure I determine the volume, probably around 100mL, and I will also determine the volume of samples, probably around 10 mL.

[Borek]

Use this information to calculate mass of acid dissolved in each of the samples.

It won't be "volume around", you should use volumetric glassware to measure exact volumes.

http://www.titrations.info/pipette-burette

[student12345]

Ok thank you. I am planning on using a pipet, I am just not sure yet what the volumes will be. So should I cross multiply to find the mass in each sample? For example if 20 grams are dissolved in the first 100mL, then 2g will be in 10mL?

[Borek]

Yes.