Stoichiometry Lab Report

Analyzing the Identity of a Metal Carbonate using Stoichiometry
Introduction:
In this lab, I determined the identity of an unknown carbonate. Based off of the mass percentage of this unknown carbonate, I was able to determine whether it was sodium carbonate, potassium carbonate, or rubidium carbonate. The purpose of this lab was to determine the mass percentage of said unknown carbonate in the given precipitate. The method used to determine this was called gravimetric analysis. There are many gravimetric analysis methods, but the one used in this lab, measured mass via precipitation. The ion, analyte, Strontium Carbonate was precipitated in a Büchner funnel apparatus with 150 mL of deionized water and a calculated amount of Strontium Chloride

The mass percentage of unknown carbonate was 57.58%, this was ±0.98% more than the calculated percent mass of sodium carbonate. There was more metal carbonate in my sample than predicted in my brain. This calculation means that I discovered sodium carbonate. I didn’t predict so many students would discover potassium carbonate. We all had different amounts of the unknown carbonate between 1.0g ±0.1g-3.0g±0.1g. The slope of the graph is positive except for a few outliers. I know that my data was an outlier. To answer the question, did it matter how much unknown compound was investigated with respect to percent of carbonate in the sample? I believe it did matter how much of the unknown carbonate was investigated. We were instructed to measure about 1.0g or about 3.0g not exact amounts. I feel like exact measured amounts would have reduced the amount of outliers in the graph. The class data changed my confidence in identifying the unknown because twelve out of twenty students discovered the same compound, where as my discovery was an

I enjoyed using the Büchner funnel apparatus. If I had more time in lab I would love to use Büchner funnel apparatus on different compounds. It makes me wonder how else can we utilize this piece of equipment. I’d also like to use more acidic chemicals to find different precipitates and practice properly disposing of acidic chemicals again, as executed in a previous lab. In CH 221 we practice stoichiometry. The stoichiometry used in this lab can be executed in the clicker questions, textbook problems, on sapling, or on ALEKS. Stoichiometry helps with conversions. We also practice stoichiometry to find the mass percentage, percent yield, theoretical yield, and mass of an element. All of these conversions can be used in this lab. The work executed in this lab can relate to that of producing washing soda. Washing soda is used in a laboratory setting and used in a household setting. To produce the proper amount for household use a factory needs to be able to synthesize sodium carbonate; measure out sodium carbonate, and correctly mass sodium carbonate. This process can help for the proper amount per single item distribution. Each item has its own said mass of sodium carbonate mixed with another cleaning