Formal Lab Report

In this experiment, we were given three main goals to accomplish. We were to identify the compound through a series of organized experiments and analyze as many physical chemical properties as possible.

Purpose: The purpose of this experiment is to learn about and use the Scientific Method. The discussion of physical properties such as density, color, texture, smell, and solubility will take place.

The purpose of this lab is to determine the chemical and physical properties of an unknown substance. Then, through the use and practice of some basic techniques used for analyzing compounds, find a compound that shares similar traits. Some of these basic techniques that were performed include: using a magnifying glass to determine the physical characteristics, solubility, conductivity (solid state/aqueous solution), pH test of the aqueous solution, reactivity test with Lead Nitrate, Hydrochloric Acid, and Sodium Hydroxide, a flame test, and melting point based on the time it took to reach it within 20 seconds. With these tests one can narrow down unknowns using the results, and then finally run confirmatory tests to solidify the findings.

The objective of this lab was to identify different substances based off their physical properties, which are characteristics of a substances that enable us to distinguish it from other substances.If each of the substances that are used are different then they will be distinguishable by their physical properties. To determine the differences we used; solubility, which is the property of a solid, liquid, or gaseous chemical substances (solute) to dissolve in a solid, liquid, or gaseous solvent to form a solution. We also used density, the degree of compactness of a substance, and the melting and boiling point of the substances which gave the degree temperature at which each substances would melt or boil.

In Part A of the experiment, the Unknown Substance #4 was found to contain Silver. Since no precipitate was formed in Step 6 of the experiment, it was confirmed that there was no presence of lead. Step 8 verified that the unknown solution contained Silver, with the formation of the white AgCl precipitate. Silver was reasonable since it was confirmed that it was not Lead. Part B of the experiment resulted in the identification of Barium. The presence of Barium was confirmed in Step 13, with the formation of the white BaSO4 precipitates in the orange solution. The unknown solution was further tested to avoid a false positive confirmation of Calcium in Step 14. No precipitate was formed so the solution in the 1M K2C2O4 so the Barium was once again verified. Barium was reasonable since it had been

The experiment requires a burette; 5-mL pipette; 2-mL pipette; 1-mL pipette; fourteen 50-ml glass-stoppered bottles; 0.5 N sodium hydroxide; phenolphthalein, methyl acetate, concentrated HCl, glacial acetic acid, and absolute methanol.

Procedure To perform the experiment five chemical reactions where used: NaCl, NaI, Na2CO3, Na2HPO4 and Na2SO4. The unknown substance (unknown #8) would also serve as a chemical reaction, but would be separate from the five chemicals because it’s one of the five reactions that’s trying to be determined. Chemical standards, HNO3, Ba(NO3)2 + HNO3, AgNO3, AgNO3 + HNO3 and Thymol Blue, were also used to assure accuracy of the unknown

The solubility test was done first to help eliminate some of the possible solutions. When the solubility test was conducted, 5.0 mL of water and 0.5 grams of the unknown compound was used. The 0.5 grams of the unknown compound

The purpose of this experiment was to determine the melting point and the boiling point of various unknown solids and liquids supplied by the laboratory. In the process of exploring the most basic physical properties of the given samples, skills such as: proper determination of compound purity through different means and how to

The main motive of the lab was determine the unknown substances identity by its tested characteristics. Considering the results of the lab, substance #1 would be a metal since it has metallic characteristics. A few metallic characteristics are a high melting point, insoluble in water, and a good conductor of a solid and liquid. All of these characteristic are cohesive with the observations made. It had a melting point above 500°C, it did not dissolve in water, and it was a good conductor as a solid and a liquid. It also looked and felt similar to what other metals do. Since it did not dissolve in

In this lab, proper laboratory technique was implemented to have the experience in the lab. Furthermore, the unknown solution needed to be investigated, to determine the solution’s macromolecules. Three methods were comprised to determine the unknown, but a set of other solution was used to help as indicators to match the unknown solution’s results. It’s consisted of biuret, iodine and benedict solution.

Then we record measurements and verify if it is soluble s, Insoluble I, or sparingly soluble sp. Also recorded are observations whether, the cloudiness indicates its solubility. Each is repeated for each solvent. Then calculate density and identify unknown. With density calculated and results obtained, now you can proceed to obtain the boiling point and melting point of to reach identity of unknown substance. The density of unknown solid was determined to be 1.071 g/ml since initial volume of water in beaker was 6 ml and finial volume with substances added to was 7.4, the mass was 1.5, whereas the calculation for d is d=m/v, resulting in 1.071. following use of apparatus to obtain boiling point using thermometer and beaker of 250ml over Bunsen burner with lit flame, with 3ml of unknown in test tube. Heat until changes in temperature and observation of physical change. Then record results. Boiling point determined was 57 degrees Celsius and estimated boiling point range was between 54 and 57. Using chart to compare data results obtain and select identify of unknown substances and elaborate as to why selected substances best fits

Before any tests were performed, a list of thirty-three compounds with their molecular weight, chemical formula and structure, and melting points was compiled. This list was used to compare with the results of our tests. Using Mel-Temp® device number 2 the melting point test was conducted as the first test. Approximately 3mm of the unknown was obtained using a capillary tube. This sample was placed in the center of the device and the device was turned on to setting four. When the sample first began to liquify and when the sample was completely melted the

A solution of the salt was prepared and 4 drops of AgNO3 (10%) solution were added. This created an off-white creamy precipitate. In order to be sure that this was not a false positive, three drops of nitric acid (6 M) were added. As the precipitate did not dissolve this meant that the unknown anion had a halide. To confirm which halide it was, a fresh solution of the salt was created and acidified with a few drops of HNO3 (6M). This was accompanied by 1ml of chloroform, an organic solvent. The addition of a few drops of NaOCl solution, swirled gently as the drops made contact with the unknown created a brown-yellow

To test the anion present in the compound, the investigators mixed the unknown with other known compounds and observed the resulting reactions. The first anion test was performed by mixing the unknown solution and silver nitrate and then adding in ammonium. No precipitate was formed from that reaction so the unknown compound could not be bromide or iodide. The second anion test was performed by mixing the unknown solution with barium chloride. A milky white precipitate formed from that mixture so the anion present in the unknown compound was sulfate.