Analysis/Conclusion:

The purpose of this lab was to use gravimetric analysis to obtain the formula of an unknown sulfate sample. Gravimetric analysis was performed by transforming the analyte into a water soluble form which precipitated out of the solution and was then isolated by filtration and drying. The analysis was completed by obtaining the mass of the sample. The mass, number of moles, and percentage of sulfate content in the precipitate were then determined from the mass and stoichiometric considerations. Based upon the theoretical percentage of the sulfate content in the unknown sulfate sample, 76.9%, it can be inferred that the unknown sample was MgSO4 for its SO42- content, 79.8%, was closest to the experimental result.

During this lab the percent error was calculated as 3.78%. This is a rather high percentage, indicating a high amount of error during this experiment. Error may have occurred when filtering the precipitate. Some of the precipitate may have remained in the filter paper due to unthorough rinsing. The filter paper may have also not been able to burn off enough, leaving some ash in the crucible, and thus resulting in flawed measurements. In future labs, I would suggest more trials, for more trials only produce more plentiful and accurate data. I would also suggest a longer burning period, allowing the ashless filter paper to truly burn off, and a more thorough rinsing during filtration in order to preserve the entire precipitate.