Discussion Of Results
In order to discover the initial properties of the unknown compound, the group performed qualitative, quantitative, conductivity, anion, and cation tests. For the qualitative solubility test, solvents used were water, toluene, and acetone; the test helped determine if the compound was ionic or polar. The unknown dissolved in water, which had a pH of 7, therefore the compound was polar or ionic. The unknown did not dissolve in toluene or acetone, proving that the compound was not nonpolar. During the quantitative test, group members placed two grams of the unknown compound ten milliliters of water and measured how much compound would dissolve in a given volume of solution. Using an Erlenmeyer flask and a volumetric pipet, the students dissolved two grams of the unknown into ten milliliters of water and a precipitate
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was formed, which we later weighed. Next, the group determined the conductivity of the unknown substance using a voltmeter. The students tested the voltage of water, which was 0.22V, and the voltage of the unknown with water, which was 0.006V—proving that the compound is conductive. The group then performed five anion experiments with the unknown compound; experiments included testing for chloride, sulfate, acetate, nitrate, and carbonate. To begin, the group performed the tests on a known compound in order to later compare the results with the results of the unknown compound. During the chloride test, the unknown was mixed with HNO3 and AgNO3. The compound did not fully dissolved, but created a white precipitate. Next, the unknown was mixed with HCl + BaCl2 for the sulfate test. A white, thicker precipitate was formed, therefore the results were positive. For the acetate test, the unknown, H2SO4 , C2H6O were mixed together, however, a fruity smell was not present. The next test the students performed was for the presence of nitrate. The unknown, H2SO4, and FeSO4 were mixed together, but the results came out negative, as there was no brown bring to be seen. The final anion test was for carbonate, which is when the students mixed the unknown with HCl. The results were negative since there was no effervescing and nothing happened. After the test, the group realized the cation was either chloride or sulfate since the unknown reacted with AgNO3 and BaCl2. Finally, the lab group tested the unknown compound for cations using a flame test. A student dipped a metal wire in the unknown and held the wire over a Bunsen burner to check for flame coloration. The color appeared to be bright orange/yellow, signifying that the cation was sodium and had a high intensity. For the filtration test, 0.5 grams each for both the known and unknown substances were measured out. Then, the substances were each added to water and BaCl2 and stirred. Then, the mixtures were placed into the centrifuge for five minutes. The solutions were later placed through the vacuum filtration. From there, the filter papers were placed in the oven to dry out the precipitate. The fully dried precipitate was measured in order to find the mass. After performing the various experiments, the group concluded that their unknown compound was Sodium Sulfate. Though the group ran into some discrepancies, such as issues discovering the anion and misinterpreting the data, they went through the procedures multiple times to make sure the results were accurate. Scientific Explanation For the flame test, when an element is burned over a Bunsen burner, the electrons fall to different energy levels, as they become more excited.
The electrons then emit a photon of light. The light for the corresponding wavelength is determined by specific energy level of the certain element, resulting in different colors to appear. Due to sodium’s photons, a yellow and orange light is projected. For the chloride anion tests, the silver salts found in the unknown compound were insoluble, because a mixture between sulfate and silver is insoluble according to the solubility rules; therefore, when mixed with nitric acid and with silver nitrate, a precipitate was formed. The anion would only be chloride if the other four tests proved to be negative. The sulfate anion test also proved positive, as a white precipitant was formed when the unknown substance was mixed with barium chloride and hydrogen chloride; the mixture between barium and sulfate is also insoluble according to the solubility rules. For the acetate, nitrate, and carbonate tests, the results came out negative because there was no definite chemical reaction with the
unknown.
Solid A was identified to be sodium chloride, solid B was identified to be sucrose, and Solid C was identified to be corn starch. Within the Information Chart – Mystery White Solid Lab there are results that distinguishes itself from the other 4 experimental results within each test. Such as: the high conductivity and high melting point of sodium chloride, and the iodine reaction of corn starch. Solid A is an ionic compound due to its high melting point and high electrical conductivity (7), within the Information Chart – Mystery White Solid Lab there is only one ionic compound which is sodium chloride, with the test results of Solid A, it can be concluded that is a sodium chloride. Solid B was identified as sucrose due to its low electrical
The purpose of the Unknown White Compound Lab was to identify the unknown compound by performing several experiments. Conducting a solubility test, flame test, pH paper test, ion test, pH probe test, conductivity probe test, and synthesizing the compound will accurately identified the unknown compound. In order to narrow down the possible compounds, the solubility test was used to determine that the compound was soluble in water. Next, the flame test was used to compare the unknown compound to other known compounds such as potassium chloride, sodium chloride, and calcium carbonate. The flame test concluded that the cation in the unknown compound was potassium. Following, pH paper was used to determine the compound to be neutral and slightly
The unknown bacterium that was handed out by the professor labeled “E19” was an irregular and raised shaped bacteria with a smooth texture and it had a white creamy color. The slant growth pattern was filiform and there was a turbid growth in the broth. After all the tests were complete and the results were compared the unknown bacterium was defined as Shigella sonnei. The results that narrowed it down the most were the gram stain, the lactose fermentation test, the citrate utilization test and the indole test. The results for each of the tests performed are listed in Table 1.1 below.
Compress the safety bulb, hold it firmly against the end of the pipette. Then release the bulb and allow it to draw the liquid into the pipette.
The primary goal of this laboratory project was to identify an unknown compound and determine its chemical and physical properties. First the appearance, odor, solubility, and conductivity of the compound were observed and measured so that they could be compared to those of known compounds. Then the cation present in the compound was identified using the flame test. The identity of the anion present in the compound was deduced through a series of chemical tests (Cooper, 2009).
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
A spectrum is a group of light wavelengths that are ordered in relation to their wavelength length. The electromagnetic spectrum consists radio waves, microwaves, infrared, visible, ultraviolet, X-rays and gamma rays. (1)Specifically, this lab looks at the visible light part of the spectrum because one of the colors in the visible light spectrum is shine through the sample. The visible light spectrum consists of colors of red, orange, yellow, green, blue, indigo, and violet. The color chosen to be shine through the sample is affected by the color of sample when mixed with the indicator Ammonium Vanadomolybdate (AMV). The color on the color wheel that is opposite of the solution’s color is the color that is shined through the
the ones that contains ppt in half, then add 6M NH3 to one set of them
1-Butanol with intermediate polarity was soluble in both highly polar water and non polar hexane as 1-butanol can be either polar or non polar compound. 1-Butanol was polar based on the general rule of thumb stated that each polar group will allow up to 4 carbons to be soluble in water. Also, 1-butanol can be non polar due to their carbon chains, which are attracted to the non polarity of the hexane.
By doing this experiment, I can know the physical and chemical properties of these samples. After I get my results about the physical and chemical properties of these samples, I can compare my results with the information given by the past student and identify the 5 unknown samples, finding out which sample is which substance. Hypothesis = ==
Solubility is defined as the maximum amount of a substance that will dissolve in a given amount of another substance at constant temperature and pressure. Solubility is typically expressed in terms of maximum volume or mass of the solute that dissolve in a given volume or mass of a solvent. Traditionally the equilibrium solubility at a given pH and temperature is determined by the shake flask method. According to this method the compound is added in surplus to a certain medium and shaken at a predetermined time. The saturation is confirmed by observation of the presence of un-dissolved material. Saturation can also be reached if the solvent and excess solute is heated and then allowed to cool to the given temperature. After filtration of the
1. The labels have fallen off of three bottles thought to contain hydrochloric acid, or sodium chloride solution, or sodium hydroxide solution. Describe a simple experiment which would allow you to determine which bottle contains which solution.
boiling point, density and solubility. We also had to see if it had an odor and
The actual, theoretical, and percent yield of sodium chloride was found. Sodium Carbonate was mixed with hydrochloric acid and the liquid was boiled until there was nothing left. The result was the production of salt, or sodium chloride.
Examining the Effects of pH Level on Lead Concentration Dr. Couper Azzara Nincevic 5 October INTRODUCTION PURPOSE The purpose of this experiment is to investigate how the pH of a solution affects the lead concentration of that solution after a lead sinker is submerged for 24 hours. The independent variable is the pH of each solution group; the dependent variable is the lead concentration of the solution after 24 hours. BACKGROUND RESEARCH The element lead has atomic symbol Pb and atomic number 82 (Gagnon, n.d.).