Verna Wang Hannah Palmer CHEM 101-069 Lab 11-19-16 Stoichiometry and Limiting Reagents Lab Report Purpose: We are using the reaction of sodium hydroxide and calcium chloride to illustrate stoichiometry by demonstrating proportions needed to cause a reaction to take place. Background: Just like a recipe would call for a specific amount of one ingredient to a specific amount of another, stoichiometry is the same exact method for calculating moles in a chemical reaction. Sometimes, we may not have enough of or too much of one ingredient , which would be defined as limiting and excess reagent, respectively.
We isolated our crude yield while comparing 2 purification techniques: column chromatography and recrystallization. TLC, NMR, and IR spectroscopy were used throughout the process to identify ferrocene and acetylferrocene in addition to evaluating the levels of purity. Evidence: The objective of our experiments was to prepare acetylferrocene from ferrocene. The overall reaction was carried out using 6.1 equivalents of liquid acetic anhydride to 1.8 equivalents of phosphoric acid and concluded with an aqueous workup with NaOH.
In addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.
One of the reactions you observed resulted in this product: NaCl + H2O + CO2 (g)? What well did this reaction occur in? Describe how the observations for this reaction support your answer. B BoldI ItalicsU Underline Bulleted list Numbered list Superscript Subscript70 Words A reaction I observed in number 1.)
Although .7906 mg of phosphonium salt was added, this probably was not enough to complete the reaction. The only significant change throughout method was 1 was that the yellowish mixture became slightly lighter. However, it was found that after vacuum filtration, there was some white and yellow
In this test, primary halides precipitate the fastest while secondary halides need to be heated in order for a reaction to occur. Comparison of the rates of precipitation of the obtained product to standard 1° and 2° bromide solutions will show whether the product is a primary or secondary
TLC was used to identify the actual unknown product as well as other products/reactants present in the filtered solution. The procedure was conducted by placing a TLC plate in a developing chamber that is filled with a small amount of solvent. The solvent cannot be too polar because it will cause spotted compounds on the TLC plate to rise up too fast, while a very non-polar solvent will not allow the spots to move. The polarity of the spots also determines how far it moves on the plate; non-polar spots are higher than polar ones. After spots on the TLC form, the Rf values are calculated and used to analyze the similarity of the compounds.
Next, is the verification and determination of pure liquids. A clean and dry a 25mL graduated cylinder must be gathered from the lab cart, weigh the dry cylinder to the nearest mg and record the data. Add distilled water to the cylinder making sure the water level is at above the 20mL mark but below the 25mL mark. Determine and record the temperature of the water in the cylinder. Then, reweigh the cylinder to the nearest milligram.
Introduction: In this lab, of water in a hydrate, or a substance whose crystalline structure is bound to water molecules by weak bonds, is determined by heating up a small sample of it. By heating, the water of hydration, or bound water, is removed, leaving only what is called an anhydrous compound. Based on the percent water in the hydrate, it can be classified as one of three types: BaCl2O ⋅ 2H20, with a percent water of about 14.57%, CuSO4
The temperature in our experiment was not very high which didn’t result in denaturation of peroxidase. The temperature seemed to be a constant that didn’t affect the experiment. If the temperature was higher in pH 3 and low in pH 10, then it would cause pH 3 to denature even more which would make the pH 3 total about 4.0. Substrate concentration basically means the amount used for the substrate. The substrate in our experiment was 0.1% hydrogen peroxide.
The titrations were all a bit different and that was because they all contained different liquids. The first titration, acid into water, showed a noticeable drop in ph after approximately 5.5 mL of acid was added and was consisted in showing low numbers. This determined that the first hypothesis, stating that the pH would go up when acid was added into water, was false. Dissimilarly to the second titration, base into water, the pH showed a noticeable increase after around 10 mL of base was added and once again, remained consistently high in pH. The third titration, acid into liver homogenate, the pH decreased a bit at 8 mL of acid, but remained fairly consistent at 12 mL. The fourth titration, base into liver homogenate, opposite to the the previous graph, increased in pH slightly at 20 mL, but once again, stayed consistent from then on out.
What happens during this stage of the experiment showing visual change and acidic reaction that is becoming weaker as the molecules are deprotonated to become equal parts within the solution. So by finding the molar ratios we learned that acid to base are 1:1 when equally balance or concentrated. So therefore concentrations at stoichiometric end point can be found by plugging in the values to formulate a dilution equation as seen above. When expressing calculations I found when doing the Titration of an Unknown Acid I discovered that with .1 mL of Sodium Hydroxide and at least 10 mL Anthocyanin as/or acetic solution will produce an average molarity of 0.9 or higher according to my
The second step is about finding the theoretical yield, which will help to determine the correct amount of Ca(OH)2 can be made in chemical reaction. However, before doing this, it’s necessary to find whether CaCl2 or NaOH is a limiting reagent. For each test, the limiting reagent is found by multiplying the number of moles of the reactant by 1 mole of Ca(OH)2 and dividing then by a number of moles of reactant from the reaction. The lowest answer in each test will be the limiting reagent. To find a theoretical yield, the limiting reagent was multiplied by the molar mass of Ca(OH)2 and
Purpose The purpose of this experiment was to evaluate the stoichiometric relationship between the testing agents and to identify the products formed. The relationship was found by completing three acid and base neutralization reactions using phosphoric acid, which is a triprotic acid, with different volumes of sodium hydroxide. Introduction Procedure Phosphoric acid solution with a volume of 1.00 mL and a molarity of 6.00 M was transferred into a 125-mL Erlenmeyer flask using a volumetric pipette.