Calculate the endpoint volume

Question

The total volume required to reach the endpoint of a titration required more than the  total volume of the buret. An initial volume of 49.64 ± 0.06 mL was delivered, the buret was refilled, and an additional 1.38 ± 0.05 mL was delivered before the endpoint was reached. The titration of a blank solution without the analyte required 0.34 ± 0.04 mL. Calculate the endpoint volume corrected for the blank and its absolute uncertainty.

Note: Significant figures are graded for this problem. To avoid rounding errors, do not round your answers until the very end of your calculations.

volume:_____ mL

± : ______mL

Answer 1

Total volume will be the addition of the two titration volumes minus the volume used for the blank. The uncertainty will be the sum of the uncertainties for each measurement.

Total volume = 49.64 ml + 1.38 ml = 51.02 ml

Less the volume of the blank = 51.02 ml - 0.34 ml = 50.68 ml

Uncertainty = 0.06 ml + 0.05 ml + o.04 ml = ± 0.15 ml

Volume = 50.68 ml

± 0.15 ml