Goals The overall goal of this project was to identify an unknown ionic compound; each group was assigned a small container filled with 5 grams of an unknown ionic compound. In order to be able to identify the unknown compound, we had to do several preliminary tests, cation tests, anion tests, and a reactivity test. Throughout these three weeks, we will identify a compound and its qualities just by looking at it. We also made quantitative and qualitative solutions and tested the compounds' pH, conductivity, and melting point. In the first week of this experiment, we had to gain an understanding of the identities of a known compound, potassium permanganate (KMnO4), so we could have a baseline to compare the rest of our results. For example,
…show more content…
First, we had to do preliminary, cationic, and anionic tests with compounds and reactions that we knew would produce a specific reaction. In our preliminary test, we used Potassium Permanganate (KMnO4) to see the physical characteristics of an ionic compound. Looking at the KMnO4, we could tell it would be salt because it was solid and granular. Because it was a salt, we could infer it would be a good conductor with a high melting point; see Table 1 of week 1 for results. We could also check the solubility by dissolving a bit of the compound in different acids, bases, and other liquids; KMnO4 is soluble in acids and water but not bases. Then, we moved on to our anion test with different compounds and reagents to see what compounds would create a specific reaction. Whether or not a reaction would happen would indicate the presence of anions; for example, we took a pinch of sodium sulfate and added it to a test tube, added 1mL of hydrochloric acid, and then added barium chloride to the test tube. This reaction formed a white, milky precipitate, indicating sulfate ions' presence; see Table 2 of week 1 for results. Then we moved on to our cation test; this test involved a pH test, flame test, and more reaction tests. In one of our tests, we reacted ammonium nitrate with sodium hydroxide to create a solution; then, we tested the solution with pH and turmeric powder, which …show more content…
In all of the ionic compounds, all of the salts were solid, a good conductor, and had a high melting point. This is common for most ionic compounds because the cations and anions have strong crystal lattices, which require a lot of energy or heat to break the bonds (Libretext 3.6)2. One aspect we used in all three weeks of this experiment was the solubility chart. There tends to be a pattern when measuring the solubility of specific ions, so there is a chart to record these patterns, which is what we relied on in the last week of the lab (Bodner Research Web)1. Since we assumed our ionic compound was calcium chloride, we chose a reagent that included soluble salts to confirm our prediction. For our first reagent, we chose to mix Na2SO4 with calcium chloride and our unknown compound to see if a precipitate would form; a precipitate would form, which confirmed our test. Other reagents we used to confirm our predictions were Na2CO3 and K2SO4, which formed a precipitate. Each week, we would take a compound, whether random or unknown, and see if it was soluble in acids, bases, and other reagents. By mixing certain compounds and reagents, we could force a reaction, specifically a precipitate, which would help us identify the presence of a specific ion. One article says that “reagents like silver nitrate or acids like hydrochloric acid or sulfuric acid can
First, we had to do preliminary, cationic, and anionic tests with compounds and reactions that we knew would produce a specific reaction. In our preliminary test, we used Potassium Permanganate (KMnO4) to see the physical characteristics of an ionic compound. Looking at the KMnO4, we could tell it would be salt because it was solid and granular. Because it was a salt, we could infer it would be a good conductor with a high melting point; see Table 1 of week 1 for results. We could also check the solubility by dissolving a bit of the compound in different acids, bases, and other liquids; KMnO4 is soluble in acids and water but not bases. Then, we moved on to our anion test with different compounds and reagents to see what compounds would create a specific reaction. Whether or not a reaction would happen would indicate the presence of anions; for example, we took a pinch of sodium sulfate and added it to a test tube, added 1mL of hydrochloric acid, and then added barium chloride to the test tube. This reaction formed a white, milky precipitate, indicating sulfate ions' presence; see Table 2 of week 1 for results. Then we moved on to our cation test; this test involved a pH test, flame test, and more reaction tests. In one of our tests, we reacted ammonium nitrate with sodium hydroxide to create a solution; then, we tested the solution with pH and turmeric powder, which …show more content…
In all of the ionic compounds, all of the salts were solid, a good conductor, and had a high melting point. This is common for most ionic compounds because the cations and anions have strong crystal lattices, which require a lot of energy or heat to break the bonds (Libretext 3.6)2. One aspect we used in all three weeks of this experiment was the solubility chart. There tends to be a pattern when measuring the solubility of specific ions, so there is a chart to record these patterns, which is what we relied on in the last week of the lab (Bodner Research Web)1. Since we assumed our ionic compound was calcium chloride, we chose a reagent that included soluble salts to confirm our prediction. For our first reagent, we chose to mix Na2SO4 with calcium chloride and our unknown compound to see if a precipitate would form; a precipitate would form, which confirmed our test. Other reagents we used to confirm our predictions were Na2CO3 and K2SO4, which formed a precipitate. Each week, we would take a compound, whether random or unknown, and see if it was soluble in acids, bases, and other reagents. By mixing certain compounds and reagents, we could force a reaction, specifically a precipitate, which would help us identify the presence of a specific ion. One article says that “reagents like silver nitrate or acids like hydrochloric acid or sulfuric acid can