Standardization Of Edta Lab Report

Vu Ngo
% MgO Determination
September 10, 2012

Procedure:
Reference to lab manual
Data:
Mass of Na2EDTA∙2H2O, g | .9289 |
Standardization of EDTA Solution | Trial 1 | Trial 2 | Final buret reading, EDTA (mL) | 18.5 | 36.7 | Initial buret reading, EDTA(mL) | 0.5 | 18.5 |
Determination of % MgO of Unknown Unknown Number | 4J | | Sample 1 | Sample 2 | Sample 3 | Mass of sample (g) | 0.2135 | 0.2132 | 0.2139 | Final buret reading, EDTA (mL) | 73.5 | 74.2 | 74.2 | Initial buret reading, EDTA(mL) | 0.5 | 0 | 0 |
Measurement of water blank Final buret reading, EDTA(mL) | 14.5 | Initial buret reading, EDTA(mL) | 14.2 |
Sample Calculation:
Given:
Molar mass of Na2EDTA*2H2O, g/mol | 372.25 | Expected M of EDTA
The measurement using the the buret have a +/- .1mL error. These types of measurement error are based on the sensitivity of the instrument, during the measurement. These errors could cause the result to deviate from the actual answer.
During the experiment, using titration to find the end point. Because of the end point was unknown, a single drop could determine its end point. There might be an extra drop that caused the data to vary as both parts of the experiment have determined. The first trial of both the experiment, the number is different, because of the unsure number of drops. Using the result from the first trial, the result of the second trial was more accurate. As proven from the experiment of determination of percent of MgO of the unknown. The sample 2 and sample 3 testing results in similarity that differ from the sample one. The sample used 73.0 ml of the EDTA solution, while both samples 2 and 3 used 74.2 ml of EDTA solution. This will cause a tip in the result toward a lower number used to find the end point. This error is not a major factor since it is only of my 1.2 ml of the actual result. The percent of all three result of MgO is different under 1 percent different. Thus, a very reasonable result in all three of the