Observations: 1. The first step had to be repeated due to not following proper instructions. I did not grease the screw, so as I was shaking the mixture, solids were forming around the screwpart of the separatory funnel. 2. When adding 5.0 mL of NaOH to the unknown mixture and shaking it for about 30 seconds, layers had formed. 3. Upon adding 20 drops of NaOH, a white precipitate was formed signifying acidic impurity. In the second NaOH mixture, about 20 drops were administered and no precipitate formed indicating that the ample is more pure than before. Data: Weight of flask = 75.10 grams Weight of the flask with solids = 75.33 grams Weight of the unknown = 0.23 grams Calculation : 75.33-75.10/0.36x100 = 63.8 % recovery Melting point of
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The converse was true for the 5% NaCl solution without Elodea and the 5% solution with Elodea (table 1). A comparative observation revealed that the beaker with Elodea in salt solution required more NaOH than did the beaker with Elodea in tap water (figure 1). Table 1. The number of drops of NaOH in each beaker Beaker Name Number of Drops Tap Water
Next, about 10 mL of both solutions, Red 40 and Blue 1, were added to a small beaker. The concentration of the stock solution were recorded, 52.1 ppm for Red 40 and 16.6 ppm for Blue 1. Then, using the volumetric pipette, 5 mL of each solution was transferred into a 10 mL volumetric flask, labelled either R1 or B1. Deionized water was added into the flask using a pipette until the solution level reached a line which indicated 10 mL. A cap for the flask was inserted and the flask was invented a few times to completely mix the solution. Then, the volumetric pipette was rinsed with fresh deionized water and
The purpose of the “Titration of the Unknown Acid” lab is to determine how much of a given material known as concentration is in a substance or mixture. In this lab, the student also learns the technique of using titration. The concentration of the acid we used in class will be sampled with a standardize solution such as sodium hydroxide with an environmentally indicator to show the physical change of color that occurs to the solution by the acid. The equipment necessary for the titration experiment follows: 0.1M NaOH, Acid solution, Anthocyanin (which is found in red cabbage leaves) indicator, Burets, Ethanol 95% and DI water. First Professor Greenberg assign a labeled unknown acid solution, then we recorded the solution’s identity and bottle code.
The purpose of this experiment was to use a pH meter to graphically determine a stoichiometric point, to determine the molar concentration of a weak acid solution and the molar mass of a solid weak acid, and to determine the pKa of a weak acid. In part A of the experiment, the unknown named Luke Skywalker was used during the experiment. Throughout the experiment the experimenter collected measurements such as the number of moles of NaOH to stoichiometric point (0.00115 mol, 0.00105 mol) and the molar concentration of the unknown acid (0.046 M, 0.042 M) during part A of the experiment. During Part B of the experiment the experimenter collected buret readings of NaOH and determined the stoichiometric point and volume of NaOH dispensed. Based
Nevertheless, the recovery of the product does make sense because it is lower than 100% which means impurities were removed. The lost amount of product was about a third of the original mass. The increase melting point range of 52-60 to 59-64 for the product shows that impurities were removed because a pure product has a higher melting point range. The melting point of the product is slightly higher but still, falls around the melting point ranges of two possibilities.
The hypothesis for the different experiments is that with each of the different substances and mixtures will be different depending on what they are. II Equipment The late nite lab was used to conduct this experiment. The product used were a balance, a graduated cylinder, water, Ethanol, and unknown liquid, Iron and an unknown metal. III Procedure
The volumetric flask was then filled up to its 100 mL mark with deionized water. The buret was washed out with dionized water and then with the strong base NaOH before being filled up with NaOH. About 20 mL of the unknown weak acid was pipetted into a beaker. The starting volume of the NaOH in the buret was recorded before about 4 mL of the strong base was titrated into the weak acid solution. The final volume was recorded.
I noticed that all 3 different substances provided had a different density. When I put about a ½ inch of the solution “H” it was very thick almost like a jelly consistency. In addition we added another unknown solution “M” into the same test tube that contained the substance “H” we observed that the substance slinked to the bottom of substance “H” and it started creating its own layer. The two layers of solution both did not mix together and was separated by some type of density suspension. Furthermore we introduced another unknown substance “G” This was the densest liquid sinking to the bottom.
10 mL of deionized water was added and stirred until fully dissolved. 5.0 mL of 3.0 M of hydrochloric acid was slowly pipetted into the mixture and stirred. The pH was checked to be less than two. The solution was placed into an ice bath to decrease the temperature to 10°C. A vacuum filtration apparatus was built with an Erlenmeyer flask with a vacuum arm and connected to a vacuum source and secured for safety using a ring hoop.
The experiment for this report is 5, 6, and 7. In experiment 5 there are given a Sodium Hydroxide which is 4.126 g when it is weighted and a KHP also with the NaOH there’s two other experiment that are used to find the titration of molarity in the three chemical balances. In exp. 6 and 7 there using the NaOH to find titration in an acid and vinegar by going through three trails to see how much sodium hydroxide is pick in it until it turns light pink, however if it turns dark pink there’s an error in the trail.
At the start of the experiment, an unknown acid, the solute, was dissolved in DI water, the solvent, diluting the concentration of the acid. Phenolphthalein, an acid-base indicator--or a weak acid that changes color when the equivalence point is reached--was added to the solution. The solution was then titrated, a process by which a solution with a known concentration, NaOH, is added to an unknown solution, the acid, in order to determine its concentration. The reaction consisted of an unknown weak acid and NaOH, a strong base, making the reaction a weak acid-strong base reaction. Because NaOH is a strong base, the pH of the reaction--or the measure of the acidity of the solution by taking the negative log base ten of the hydronium concentration--would increase when titrating the unknown acid.
Based on the R2 values from your graphs, do you think that density trends on the periodic table are linear relationships? What rationale could you offer to explain your answer? The R2 value established from the group 4 graph demonstrates a linear relationship with a steady increase. The period IV graph provided a very low value of R² = 0.0028 on the linear trendline and presents nearly any correlation at all.
In this experiment, each of the unknown solutions were tested for the presence of chloride, nitrate, and acetate. For unknown 2, there was no precipitate formed during the chloride test, concluding that it did not contain chloride. Unknown 2 also produced a negative for the nitrate test, since a brown ring did not form, indicating that it did not contain any nitrate ions. The last test, the acetate test, was not conducted on unknown 2 due to the results from the cation tests. For unknown 4, the chloride test also produced a negative result, indicating the absence of any chloride ions.
The equation of the reaction between sodium hydroxide and ethanoic acid is as follows: CH3COOH + NaOH → CH3COONa + H2O We can measure the end point of titration process and we can also measure the amount of reactants. The concentration of ethanoic acid in the vinegar can be determined through stoichiometric calculations, Using the values obtained from the titration, and also the chemical equation as a reference. Phenolphthalein indicator is used in this acid-base titration Equipment and materials:
That caused a new initial reading of NaOH on the burette (see Table1 & 2). The drops were caused because the burette was not tightened enough at the bottom to avoid it from being hard to release the basic solution for titrating the acid. The volume of the acid used for each titration was 25ml. The volume of the solution was then calculated by subtracting the initial volume from the final volume. We then calculated the average volume at each temperature.