In this experiment we determined the mass, moles, and percent of SO4 in a precipitate. After determining the percent of SO4 in the precipitate there was one question left. What is the identity of the unknown sample? By completing the final table with the possible unknowns, I was able to determine the identity of the unknown substance. There were a couple of hints that led to my final decision. First, I knew that the substance had to be soluble in water. I kept in mind that most sulfates are soluble except for SrSO4, BaSO4, and CaSO4 since coveland bonds are typically insoluble in water except in organic solvents. This eliminates some of the choices while leaving the rest as water-soluble substances. The next thing to do was to calculate the formula weight of each unknown that was water-soluble. To obtain the percentage of SO4 in the content, the formula weight of SO4 must be divided by the formula weight of each unknown then multiplied by 100(see Sample Calculations for Percent SO4). The SO4 content that was closest to the experimental percentage was the unknown substance. After analyzing the percentages of SO4 I was able to conclude that the unknown substance was Sodium (Na2). My analysis was accurate because i followed the solubility rules (see image below) and calculated the percentage of each unknown while comparing it to the SO4 content. This experiment could be made better by making the unknown a compound instead of a single element. In the compound we could have determined the percent content of each element.

The image above shows the soluble for several compounds and elements