Gravimetric Analysis of a Soluble Sulfate

Abstract Gravimetric analysis describes the methods for finding the chemical constituent of analyte in a solution through analytical chemistry. This method uses the mass of solid SO42-, with an unknown quantity and quality, to qualitatively determine the makeup of the solid SO3-. Two separate experiments with the initial compounds of BaCl2 and SO42- were put into solution to allow for the BaSO4 precipitate to form. Through filtration and ignition of precipitate containing ashless papers, the solid masses of BaSO4 were attained. With a gravimetric factor of 1:1, sample 1 resulted in the formation of 0.5874g BaSO4 from 0.4004g of SO42-, while sample 2 resulted in the formation of 0.4073g BaSO4 from 0.3985g of SO42-. The two samples, respectively, produced a percentage of 50.32% and 35.06% SO3-; averaging a net percentage of 42.69% with a standard deviation of ± 10.79%.

Purpose The purpose of this experiment is to determine the mass of sulfate in the precipitate from the reaction of BaCl2 (aq) + SO42-(aq) → BaSO4(s) + 2Cl-(aq) while utilizing gravimetric analysis methods.

Introduction

Gravimetric Analysis utilizes the mass of a product to calculate the quantity of the original unknown analyte, Quantitative Chemical Analysis page 674. While this method of chemical analysis has been established since the eighteenth century, it is still one of the most accurate methods when determining how much unknown was present. The gravimetric analysis of a soluble sulfate lab allows for the experimenter to become better acquainted with techniques necessary for the completion of the experiment, while also understanding the pitfalls associated with carelessness and improper use of laboratory equipment. Techniques and Equipment utilized:
 Tare and Weighing
 Filtering
 Ignition of Precipitate
 Glassware Reading and Proper Handling
 Weight to Constant Mass
 M-22 Denver Instrument Analytical Balance
 Ring Stand, Ring, and

References: The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 14th ed. O’Neal, M.J.; Heckelman, P.E.; Koch, C.B.; Roman, K.J., Eds.; Merck & Co.: Whitehouse Station, NJ, 2006 p. 166 CRC Handbook of Chemistry and Physics, 81st ed. Lide, D.R., Ed.; CRC Press: Boca Raton, FL, 2000 p. 4-103 Quantitative Chemical Analysis, 8th ed. Harris, D.C., Ed.; W. H. Freeman and Company: New York, 2010 p. 674