The first goal of the laboratory was to discover the identity of the unknown compound.

The first experiment conducted was a visual test of the unknown and of the 15 known compounds.  The unknown was white and composed of small crystals.  The fifteen known were compared to the unknown and the results of that test are in Table 1.

Table 1

The table cells with the shaded backgrounds are the compounds whose appearances were dissimilar from that of the unknown.  As can be seen from the table we accidentally tested Sodium Sulfate and Calcium Chloride twice by accident and while two other compounds were tested they were not properly recorded.  However, this still left us with four possible unknowns; Sodium Chloride, Sodium Sulfate, Potassium Chloride, and Ammonium Sulfate.

 The second experiment conducted was a solubility test of the known and of the 4 remaining known compounds of which the results are shown in Table 2

Table 2

The unknown compound remained in suspension after being mixed with the water.  The shaded table cell indicates the only compound that precipitated after several minutes.  The results of this experiment narrowed the possible compounds down to Sodium Sulfate, Potassium Chloride, and Ammonium Sulfate

The third experiment was to mix all known compounds and the unknown compound with a series of chemicals.  We then eliminated any compounds that reacted differently with the chemicals than the unknown did.  The results of this experiment are shown in Table 3

Table 3

While the compounds did not react with most of the chemicals, they all reacted with HCl.  The shaded cells are the compounds that reacted differently than did the unknown compound.  From this experiment we discovered the identity of the unknown to be Ammonium Sulfate.  During the retest the smoking was eliminated when the cells did not have any water in them and began smoking when water was added to the reaction.  Thus we learned that the smoking was caused by water contamination of the cells the reactions were held in and were not part of the ideal reaction.

The second goal of the laboratory was to find two ways to synthesize Ammonium Sulfate.

Before beginning this experiment we researched the compound on the internet and found two different chemical reactions that would produce the desired compound.  The two internet pages we based this experiment are listed in the references section.

For our first experiment we mixed Ammonium Hydroxide with Sulfuric Acid to get Ammonium Sulfate, Water, and a small excess of Ammonium Hydroxide.  We then heated the compound with a Bunsen Burner to boil off the water and excess Ammonium Hydroxide to leave the solid Ammonium Sulfate behind at the bottom of the test tube.  The reaction is shown in Figure 1

Figure 1

NH₄OH + H₂SO4 --> (NH₄)₂SO₄ + H₂O + NH₄OH

For our second experiment we were going to mix Calcium Sulfate with Ammonium Hydroxide before discovering that we did not have any Calcium Sulfate.  We substituted Magnesium Sulfate for Calcium Sulfate and proceeded with the experiment.  The Magnesium Sulfate and Ammonium Hydroxide reacted to form Ammonium Sulfate, Mg(OH)₂, and excess Ammonium Hydroxide.  We then added Water to separate the Ammonium Sulfate from the Mg(OH)₂.  The Mg(OH)₂ precipitated while the Ammonium Sulfate remained suspended.  We then carefully poured the aqueous portion of the mixture into a fresh test tube leaving the Mg(OH)₂ behind.  We then used a Bunsen Burner to boil off the remaining Water and Ammonium Hydroxide leaving the desired Ammonium Sulfate behind in the test tube.