Unknown White Compound

The purpose of conducting experiment was to determine the identity of white compound. Based on the 5 gram of unknown white compound several experiment conducted including solubility test, pH test, flame test, and ion test. Several materials including chemicals used throughout experiment and will be described through paragraphs.

Solubility test was used to determine if unknown white compound was soluble in water. To conduct the solubility test, many materials were used such as flask, glass rod, scale, and chemical used was unknown white compound. First, 0.25 gram of unknown white compound carefully measured on scale. Then, the 0.25 gram of unknown white compound added to 100 mL of water and dissolved it using the glass rod. While the unknown

white compound was added to water, carefully watched whether the compound was dissolving or no. The same process was repeated with 0.50 gram of unknown white compound. To perform the conductivity test, three different trial were took places. First 0.10 gram of unknown white compound was measured and 20 mL of deionized water obtained in 50 mL of beaker. After obtaining conductivity apparatus, then placed it in the beaker. Using logger pro, the unknown white compound was conductive if the light turn green. Then, trials for 0.20 gram and 0.30 of unknown white compound was repeated with same procedure as 0.10 gram.
The flame test was also performed in order to identify the properties of unknown white compounds. First, material were gathered: Bunsen burner, matches, and deionized water. Then the Bunsen burner was set up under hood and the nichrome wire was placed into deionized water. Also deionized water was used to stick the unknown white compound to nichrome wire. After that, the Bunsen burner was lit and held the wire over it for 5 second and recorded change in color.
To determine what anions the substance contains, the following chemical test performed. First, 1 gram of unknown white substance was measured and added it to 10 mL of 50 mL of beaker. Since the formation of a precipitate indicate the presence of sulfate ion, 1 mL 6M HCl and 1 mL 0.1M BaCl2 to the solution to test if sulfate ion present. To test the presence of carbonate ion 6M HCL added to 1mL of unknown solution and record the change in carbonate ions. The presence of carbonate ions determined by the formation of carbon dioxide as bubble. The same procedure followed for halide ions. The halide ions were determined by the formation of solid , so 1mL of 6M HN03 and 1mL of 0.1M AgNO3solution to 1mL of unknown solution and record the change in the behavior of halide ions. Also to determine whether the unknown compound contain cation, flame test was used. Using clean, moistured q-tip, placed it in some of unknown compound and hold it over the hot burner flame and observe the color as it changes. This process was repeated twice using the same technique and materials.
The last and final test performed was the PH test using litmus paper. Determining whether the unknown white compound was acid, base, or neutral can be very helpful because it helps narrow down the possibility of what the unknown white compound can be from the presented 15 compound. First, 0.50 gram of unknown white compound was measured then placed in 10 mL in 50 mL of beaker. Then obtained the two different color litmus paper, (blue and red). If the litmus paper turn blue to red, then it is acid and if litmus paper goes from red to blue, then the solution is base .If the paper doesn't turn either red or blue , then it is categorized into neutral which means it is not acid or base. During the experiment, carefully watched as the color of the solution might change.
Result
Throughout many tests that was performed, the identity of unknown white compound narrowed to KCl, KNO3, NaCl, and K2SO4 from the possible 15 compounds that presented in lab that could potential be the unknown white compound.

The technique used to narrow down the identity of unknown white compound were solubility test, pH test, flame test, and ion test. The first technique used to narrowed the properties of unknown white compound was using solubility test. To conduct solubility test, 0.25 gram of unknown white compound was dissolved in 100 mL of water. After carefully observing the change while string unknown white compound in water, the unknown white compound was soluble because it dissolved in water completely. Using bursen burner, matches and deionized water, flame test was conducted for unknown compound and it burned lilac color. Then compared the color of unknown white compound to other compound that were narrowed. The results of flame test for compounds that were narrowed down is shown in the following table. The pH test was conducted using litmus paper. 0.50 gram of unknown white compound was measured and dissolved in 10 mL of water in beaker. After dissolving, placed the litmus paper in solution and recorded the pH value of unknown compound which was neutral. Then compared the pH value of unknown white compound to compound that were narrow down. The pH result of the KCL, KNO3, NaCl, and K2SO4 is presented in the following table. The ion test was also conducted in order to make sure that the identity of unknown white compound was matched with the compound that were narrow down. After conducting the test, the result of unknown white compound which formed precipitate compared to KCl, KNO3,NaCl, and K2SO4. The results shown in the following

table.