Unknown White Compound Lab Report

1. Which reactants used in this experiment are flammable? Discuss the safety precautions that are necessary when working with flammable materials in the lab?

Suppose a household product label says it contains NaHCO3. How would you test this material for the presence of sodium bicarbonate?

1 Copper (II) Nitrate Crystals in vial, Copper Metal - 6-8 pc. in bag 2"x 3"

In a chemistry stockroom, a vial of an Unknown White Compound was found. In order to properly dispose of the substance, the substance has to be identified .The possible compounds has been limited to one of 15 different compounds. Also, approximately 5 grams of the Unknown White Compound (UWC) were available for testing. In order to determine the properties of the compound, a series of tests was conducted. These tests included a ph test, a conductivity test, a flame test, a sulfate test, a halide test, an ammonium test, a solubility test, and a carbonate test. Using the results of these experiments, it was hypothesized that the UWC is potassium chloride. To further confirm the hypothesis, a synthesis of potassium chloride was conducted.

To verify that CaCl2 was the compound that had been synthesized, the compound was tested with the flame test, solubility test, halide ion test, and pH test. CaCl2 was confirmed to be the synthesized compound as the results of these tests matched the results of the unknown white compound.Introduction

Based the data collected, the identity of the unknown #42 is lithium chloride. Because the unknown compound produced a bright red pinkish flame, shown in Table 1, the possible cations based on the CRC Handbook were lithium or strontium 1.The known 1M lithium chloride also produced the same colored flame as the unknown, suggesting that the unknown compound has lithium. Since lithium produces no precipitate with the compounds in Table 2 and strontium produces a precipitate with the same compounds, the observations in Table 2 indicate that the unknown’s cation is lithium 4. Using the solubility table, process of elimination, and the results in Table 3 the possible anions for the unknown compound were chloride and bromide4. The production of precipitate

The compound was tested for the presence of ammonium, carbonate, sulfate, chloride, and nitrate, as seen in Table 2. The nitrate test produced a precipitate, indicating the presence of the nitrate ion in the compound. At this point it was hypothesized that our unknown compound was calcium nitrate.

We repeated this for a total of 6 known substances and 3 unknown substances. We also made a table for each element showing the color of the flame that we saw,

Even though the compounds provided in this lab did not come with any information, one must use their knowledge and investigative skills to formulate their own justifications for the unknown substances through performing a wide variety of tests. To elaborate, these trials are crucial for solving the identity of these compounds as each of their characteristics that they exhibit (the outcome of the experiments) are directly connected to a specific chemical compound group, whether it be metallic, ionic, polar covalent, non-polar covalent or network covalent. Unknown compound #1 and #4: First of all, it is most certain that the first and fourth unknown compounds should be classified as an ionic since their qualitative and quantitative properties

An unknown sample was massed and put into three test tubes for three different trials. A gas transfer assembly was put together and hydrochloric acid was added to each sample in each test tube. A reaction between the carbonate sample and the acid occurred and the volume of carbon dioxide gas produced was recorded. This process was repeated three times. The mass

We used a Bunsen burner, Ni-Cr wire, and the eight different metal ions for this lab. We had to place several drops from one of the solutions on the end of the Ni-Cr wire, then one person holds the wire in the flame, and the others observe the colors of each solution through the spectroscope, then record data, and then repeat each step for the other solutions. When done, clean the wire and any spills and turn off the Bunsen burner. For the unknown substance (number 3), we found out that it was barium because when we did the flame test on barium, it’s flame color was yellow and it was yellow for the unknown too. Also, the unknown and barium had the same colors on the spectroscope reading and the three colors were close to being on the same number, and the unknown didn’t fit with any of the other solutions’

A unknown was assigned by the lab instructor which contained 4-aminobenzoate, Naphthalene, and Benzoic acid. The name of this unknown was Unknown B. This unknown was mixed with 2ml of methylene chloride which separated into an organic and an aqueous layer. The aqueous layer was on top.

One of the tests carried out in this investigation is a flame test. A flame test is crucial in order to be able to identify

Sodium hydrogen carbonate was added to the solution until it becomes neutral. Ph paper was used for this test to determine its ph value.

Perhaps had the lab been executed slightly differently, a different trend would have been found, or possibly the data would have supported the hypothesis. While only given one class period to complete this lab, it is possible that it was slightly rushed, resulting in different results. Additionally, it would have been beneficial to test each element more than once to ensure that the most accurate information was being gathered. This may have led to unexpected results as something may have gone wrong with the Spectrometer and its data collection. It is also a possibility that the Spectrometer was not given enough time to fully collect the data. Perhaps it was not close enough to the flame, or it was turned off before it was finished gathering information.