CHEM 297 Study Guide - Quiz Guide: Volumetric Flask, Pipette, Approximation Error

• School: McGill University
• Department: Chemistry
• Course: CHEM 297
• Professor: Jan Hamier

Document Summary

Colorimetric determination of manganese in steel and lactose in milk via the bertrand method. The analytical balance, volumetric flask, and the burette are a source of ancillary uncertainty. Respectively, their uncertainty is + 0. 0001 g, + 0. 113 ml, and + 0. 1 ml. Normality of kmno4 = mass of n a2c 2o 4 1mol. Mean normality = (normalitytrial 1 x normalitytrial 2 x normalitytrial 3)/3 = 0. 1010 n. Percentage error = [(error) / (reading)] x 100 = [0. 1 ml / 30. 13 ml] x 100 = 0. 332% Massna2c2o4 = massinitial weight massfinal weight = (23. 9772 g + 0. 0001g) - (23. 7750 g + Percentage error = [(error) / (reading)] x 100 = [0. 0002 g / 0. 2022 g] x 100 = 0. 0989% Total uncertainty of kmno4 normality = (0. 09892 + 0. 3322)0. 5 = 0. 346% Where the random uncertainty of a 250ml volumetric flask is + 0. 08 ml then.