Unknown 3 Lab Report

The hypothesis is correct. Potassium chloride mixed with silver nitrate creates a white precipitate. Barium

Metal is responsible for the colour produced in the flame test for that salt. All salts contain

My unknown organism #6 is Morganella morganii, which is a gram-negative bacillus rods commonly found in the environment and also in the intestinal tracts of humans, mammals, and reptiles as a normal flora. (3, 5) This bacterium Morganella morganii, was first discovered in the 1906 by a British bacteriologist named H. de R. Morgan. (2) Despite its wide distribution, it is an uncommon cause of community-acquired infection and is most often encountered inpostoperative and other nosocomial settings. (2, 3) Morganella morganii infections respond well to appropriate antibiotic therapy; however, its

2. If the mineral is non-metallic, decide if it is light or dark in color.

In part 1, the precipitate that forms is a aluminum hydroxide and in part 2 it is magnesium hydroxide. A precipitate is an insoluble solid that emerges from a liquid solution. When the emergence of the insoluble solid from solution happens, it is called precipitation. The property change in the reactants of the lab are when the water, alum, ammonia, react and create the aluminum hydroxide. When the precipitate is formed, it is an endothermic reaction because the change in the product, aluminum hydroxide, decreases in temperature. This is a chemical reaction because different elements rearrange themselves to form a new substance and while they do so, they either absorb heat or give it

An unknown sample is identified using the relationship between the mass of the product and mass of the reactant in a balanced chemical equation using the involved species molar mass.

In well 4A there was a chemical reaction between the sodium chloride and silver nitrate. There was a white precipitate formation which proves there was a chemical reaction.

Purpose: The purpose behind this unknown project is to help us determine the identity of the liquid culture we have selected. With the freedom we’ve been granted, we are permitted to use any of the tests that we have performed in our previous labs to assist us with identifying the organism. This project is intended to push us to use the knowledge we have acquired, using proper staining techniques and thorough understanding of testing techniques and results to draw conclusions.

The lab performed required the use of quantitative and analytical analysis along with limiting reagent analysis. The reaction of Copper (II) Sulfate, CuSO4, mass of 7.0015g with 2.0095g Fe or iron powder produced a solid precipitate of copper while the solution remained the blue color. Through this the appropriate reaction had to be determined out of the two possibilities. Through the use of a vacuum filtration system the mass of Cu was found to be 2.1726g which meant that through limiting reagent analysis Fe was determined to be the limiting reagent and the chemical reaction was determined to be as following:-

CH 204 – Introduction to Chemical Practice Experiment 1 – (Qualitative Analysis of Cations) Sania Razzak Luis Andres Gonzales TA: Jose Enriquez February 11, 2016 RESULTS & DISCUSSION The purpose of the experiment was to identify two cations in an unknown solution using qualitative analysis. The unknown solution contained metal nitrate salts.

In this experiment, I saw that the product of Tin (ll) Chloride mixed with Potassium Dichromate is different from the product that resulted from Tin (lV) Chloride when mixed with the same reactant that was used with Tin (II) Chloride, Potassium Dichromate. They both resulted with different colours and smell. Tin (II) Chloride resulted with a light green colour, whereas Tin (IV) Chloride resulted with bright yellow colour. Similarly, Iron (llI) Chloride had a different product when mixed with Sodium Hydroxide, Ammonium Chloride added with Aqueous Ammonia, and Potassium Ferrocyanide compared to the product of Iron (ll) Sulfate, when mixed with the same reactants that was used to react with Iron (III) Chloride. And also same for Copper (ll) Thiocyanate

The purpose of this experiment was to apply the understanding of basic solubility principles and precipitation reactions to identify two unknown cations in a given solution. The first two processes involved adding various acids and basis to the unknown solution to observe different precipitation reactions. The unknown solution contained either silver or lead and either barium or calcium. For unknown solution one, adding a sample of hydrochloric acid to the unknown solution started the experiment. This was imperative because it triggered a precipitation reaction, creating PbCl2 or AgCl. HCl was an ideal acid that was used because it was soluble to Calcium or Barium but atleast partially insoluble to Ag and Pb, allowing for the Calcium or Barium to have remained in solution, become isolated in a new test tube, and set aside for later use.1 The chloride ions are much more attractive to the silver and lead ions compared to the calcium or barium, which allowed some to precipitate while others to have remained in solution.2

The cations in both the known and unknown samples were identified by using qualitative analysis, of which were determined to be acidic, basic, or neutral by using litmus paper. Acid-base reactions, oxidation-reduction reactions, and the formation of complex ions are often used in a systematic way for either separating ions or for determining the presence of specific ions. When white precipitate formed after adding hydroxide, aluminum ion was determined to be present in the solution. However, nickel was determined to test positive when the solution changed to a hot pink color after adding a few drops of dimethylglyoxime reagent and iron was present when the solution was a reddish brown color when sodium hydroxide was added to the mixture at the very beginning of the experiment. Qualitative analysis determines that ions will undergo specific chemical reactions with certain reagents to yield observable products to detect the presence of specific ions in an aqueous solution where precipitation reactions play a major role. The qualitative analysis of ions in a mixture must add reagents that exploit the more general properties of ions to separate major groups of ions, separate major groups into subgroups with reactions that will distinguish less general properties, and add reagents that will specifically confirm the presence of individual

The experiment used qualitative analysis to determine two cations in an unknown solution. In Part A, identified either silver or lead that was interfused into the metal nitrate salts solution. In Part B, calcium or barium would appear. In Part C, another method of qualitative analysis was performed by cation flame tests. The various metal chloride solutions would be used to observed and recorded the colored flame of each species. The goal was to practice qualitative strategies to be able to precipitate, separate and identify the unknown cations in the solution by used lab equipment such as the centrifuge, disposable pipette, and Bunsen burner.

The colour of the precipitate was black and were quite small in size, so it was a bit hard to distinguish between the zinc powder present and the copper formed by the displacement reaction because copper formed should be reddish brown is colour – which is also a dark colour and thus two dark colours were hard to be distinguished.