If anything was added out of order the color change would not happen. The titrant used was NaOH. The indicator for both parts of the experiment was phenolphthalein. Phenolphthalein is an indicator that changes color depending on the pH of the solution it is in.3 Specifically, phenolphthalein is colorless when the pH of a solution is acidic or neutral, but when the solution becomes slightly basic, phenolphthalein turns slightly pinkish, and then darker pink as the solution becomes more basic.3 This allows for a clear understanding of when the reaction has been
The anthraquinone dye experiment has the purpose to identify the anthraquinone dyes from unknown mixture by using thin layer chromatography (TLC) of the unknown fraction. An anthraquinone is an aromatic organic compound obtained by the oxidation of anthracene. To separate the compounds in the mixture, column chromatography and thin layer chromatography uses portioning of a sample between a stationary solid phase and a liquid mobile phase. As the stationary phase, they use either silica gel or alumina, and organic solvents as the mobile phase. In order to accomplish the experiment, an unknown which is a solution of at least two anthraquinone dyes will be used.
Purpose: The purpose of this lab is to titrate an unknown solid acid (KH2PO4) with a standardized sodium hydroxide solution. After recording and plotting the data, the acid’s equivalence point will be recorded once the color changes. Using the equivalence point, the halfway point will be calculated, which is used to determine the acid’s equilibrium constant. The acid’s calculated equilibrium constant will be compared with the acid’s established pKa value. Eventually using the NaOH and the acid’s consumed moles, the equivalent mass will be determined.
The purpose of this experiment was to synthesize a Grignard reagent with 1-bromobutane and homogenized magnesium in anhydrous diethyl ether. This solution was refluxed in a flask connected to condenser and drying tube. As seen in the mechanism, maintaining a dry condition is important to avoid the Grignard reagent from attacking water, which will result in loss of the bromine. It is important to reduce the amount of moisture and water vapors to avoid destroying the Grignard reagent, which is essential to the synthesis of 2-methylhexanol. Hence, a calcium chloride and cotton were filled inside a drying tube.
Water will act as initial solvent for caffeine extraction. This is due to water that slowly soluble with caffeine at ambient temperature but highly soluble when temperature is at 100°C. Then, methylene chloride is chosen as the extraction solvent, due to its miscibility with caffeine and immiscibility with water. As mentioned above, the immiscible pair is chose for the extraction part because to allow the aqueous and organic layers to be separated. Basically, the bottom layer is the aqueous layer while the upper layer is the organic compound.
Titration curve of NaCl and an unknown amino acid titrated with 2M HCl (blue), along with the NaCl blank (red). The graph shows the exact amount of HCl added in ml and the decrease of pH recorded during the titration. Figure 2: Titration curve of NaCl and an unknown amino acid titrated with 2M NaOH (blue), along with the NaCl titration with 2 M NaOH (red). The graph shows the exact amount of NaOH added in ml and the increase of pH recorded during the titration. It also shows that the same amount of NaCl base was used to titrate the blank.
The Benedict’s test is useful for reducing sugars. Reducing sugars are a carbohydrate that can either be straight chains with an aldehyde group at the end or as ring forms with a ketone group (Hill, 1982). Monosaccharides and most disaccharides will reduce copper (II) sulfate. The Benedict’s solution contains cupric ions and the aldehyde groups at the end of the sugars will reduce the cupric ions to cuprous ions (Cu+). There will be a precipitate of copper (I) oxide when the cuprous ions combine with oxygen (Hill,
Inoculate the test agar medium: There are two types of inoculation that can be done. Phenol Red Broth – Glucose, Lactose, Sucrose The test results are as follows: for glucose, lactose, and Unknown 361 tested A/-, meaning that acid was produced, but no gas and it tested K for sucrose meaning that there was alkaline production. Procedure: 1. Obtain one tube for each sugar, usually one for glucose, lactose, sucrose, mannitol. Do not get them confused, they look the same, it is suggested that they be labelled immediately if they are not already labelled.
Danielle Pitter CHEM 137 Professor D’Amelia 3/1/17 Extraction of a Neutral Compound from Acid and Base Impurities Discussion: The diethyl ether solvent is nonpolar; therefore, based on the expression like dissolves like, other nonpolar molecules will dissolve in it. The 9-fluorenone is a nonpolar molecule; therefore, it will dissolve in the nonpolar diethyl ether. The benzoic acid has a polar carboxyl group; however, the ring is nonpolar. The nonpolar ring in the benzoic acid is what makes it soluble in the diethyl ether. The ethyl-4-aminobenzoate is similar to benzoic acid, in that it has a nonpolar ring and has polar attachments.