Is it possible to find uncertainty for water hardness?

[FlipStyle1308]

Homework Statement

I am told to find the uncertainty for the titration part of determining the water hardness in my chemistry lab. I only have the following data:

By titrating 281.75 mL of titrant, it was determined that 532.08 ppm is the hardness of the water.Also, for water remediation, my contaminant was fluoride, and my remediation agent was 0.005 M Ca(NO3)2 aqueous solution. What is the cheimcal equation describing remediation chemistry, and what is the remediation variable to be studied?

Homework Equations

No clue

The Attempt at a Solution

I cannot find any equations that will help me, since I do not have the "actual" value that I can use to determine uncertainty. If anyone is able to help me, it'd be great. Thanks!

 

[chemisttree]

Ca(NO3)2 <-------> Ca+2 + 2NO3-

Ca+2 + 2F- <---------> CaF2(s)

Ksp of CaF2 = [Ca+2][F-]^2 = 3.45 X 10^-11

Remediation variable = [F-]