In the first part, five 100 mL flasks of 5 mL ligand solution, 5 mL 2 M sodium acetate, 4 mL 3 M NH2OH, and 1-5 mL Fe2+ solution are diluted with water. The absorption spectrum for varying concentrations of Fe2+ are measured using a spectrophotometer and the data is graphed in Excel. The slope of the line is ε in the Beer-Lambart equation A = εcl. In the second part of the experiment, eleven flasks containing diluted stock solutions of Fe2+ and ligand are mixed with 5 mL 2 M sodium acetate and 4 mL 3 M NH2OH and diluted with water. The absorption spectrum is measured using a spectrophotometer and the data is graphed in Excel.
Calculate the molarity of the original vinegar solution and its concentration in gdm-3, given that it reacts with NaOH in a 1:1 ratio. 7. 2.5 g of a sample of ethanedioic acid, H2C2O4.nH2O, was dissolved in water and the solution made up to 250 cm3. This solution was placed in a burette and 15.8 cm3 were required to neutralise 25 cm3 of 0.1 moldm-3 NaOH. Given that ethanedioic acid reacts with NaOH
Zing Substances. For ionizing substances, such as NaCl , 1mosm is 1mmole times the number of ions formed when each molecule dissociates. One mmole of NaCl is 58 mg, but when it dissociates, it yields 1 mmole of Na+ (23mg) and 1mmole of Cl ( 35mg). Therefore , 58 mg of NaCl is 2 mOsm of NaCl is put into a beaker and distilled water added to make 1 liter, the osmolarity is 2mOsm/l. A) How many mosm solute will 1 gram of NaCl yield?
Part C: Density of Sodium Chloride (NaCl) Solution, a sample of NaCl was obtained and measured using a 100mL beaker and a 10mL pipet to determine the concentration of the solution. In order to obtain the appropriate result, a calibration graph and density measurement was used to determine the concentration of the sodium chloride solution. In conclusion, based on the water temperature of 21.8°C in part A’s graduated cylinder experiment obtained, it was determined that the average density was .0973g/mL with a percentage error of 2.5%. When graphed the measurement was equal to Y=0.988x. Part B: The graduated pipet’s average density at 22.3 °C was determined to be 0.9785g/mL with a percentage error of 1.89% shows the graduated pipet to be more accurate and precise.
Twenty drops of bromothymol blue was also added to the 150mL beaker. The pH was then obtained using the Vernier pH probe and it read 6.68. The 5mL pipet was then used to transfer 5mL of the green solution to the three 50 mL beakers. A 100mL beaker was obtained and filled with 1.0 M HCl solution and the pipet was used to acquire 1mL of the 1.0 M HCl solution. The 1mL of HCl was then transferred to one of the 50mL beakers turning the color of the solution to yellow.
Percent H2O in Hydrate is equal 0.34/2.33=14.6% 3. The general formula of barium chloride hydrate is BaClg-nHZO, where n is the number of water molecules. Calculate the theoretical percent water for each value of n—divide the sum of the atomic masses due to the water molecules by the sum of all the atomic masses in the hydrate, and multiply the result by 100. Complete the table. | BaCl2 | BaCl2•H2O | BaCl2•2H2O | BaCl•3H2O | Sum of atomic masses (BaCl2) | 208.23 | 208.23 | 208.23 | 208.23 | Sum of atomic masses (nH2O) | 0 | 18.02 | 36.04 | 54.06 | Sum of atomic masses (hydrate) | 208.23 | 226.25 | 244.27 | 262.29 | Percent water in hydrate (theoretical) | 0% | 7.96% | 14.75% | 20.61% | In this lab we used a Balance, centigram
From your three trials, calculate the average volume of Na2S2O3 needed for the titration of 25.00mL of diluted bleach. 3. Use the average volume and the molarity of Na2S2O3 to determine the molarity of the diluted bleach. (Find moles of Na2S2O3, convert to moles of NaClO, and divide by volume of dilute bleach that was titrated in each trial to get M). 4.
(0.050) (0.1) = 0.0083 moles b. Pour 8.3 mL of the stock solution to get the amount needed. c. Measure out 8.3 mL in a graduated cylinder 8. Exercise 8: a. 41.8 mL are used b. 0.00079 moles EDTA4- c. 0.00079 moles ZnI2 d. 0.0517 grams of ZnI2 are in the sample e. 0.0517/0.237= 21.8% f. Error Is 6.34% Lab Report: Part 1: In this lab we used the following supplies: * Zinc Iodide * Na2H2EDTA(s) * Calmagite indicator solution * pH 10 buffer solution * 6M Acetic Acid * Unknown Zinc Compound The main purpose for this part of the lab was to determine the amount of zinc ion in a sample of ZnI2 by titration.
Date 5/8/2013 Introduction to Organic and Biochemistry CHM 132 Unit 15 Lab (Body Fluids) Buffers Report Sheet Record the properties of each of the flasks on the table below: |Property |Flask 1 |Flask 2 |Flask 3 |Flask 4 | |Contents | | | | | |Initial pH |7.0 |7.0 |7.88 |7.88 | |pH after adding strong acid |2.32 | |6.16 | | |pH after adding strong base | |11.68 | |11.79 | 1. Compare what happen to the pH of flask 1 to what happened to the pH of flask 3 when HCl was added. The pH of flask 1 dropped much more than that of Flask 3. 2. Which substance, water or the buffer does a better job of maintaining pH when small amounts of strong acid are added?
The purpose of the experiment was to do a solution, which molarity is 0.20 mol/l, from water and an ionic compound. Our ionic compound was zinc sulfate (ZnSO4). Our task was to make one hundred milliliters (100 ml) of the solution. Materials To execute the experiment we used the following equipment: - a beaker - a volumetric flask - a plastic spoon - a scale - a pipette - a funnel - a cork cap We also used solid zinc sulfate (ZnSO4), and distilled and deionized water to make the solution. Calculations To figure out the amount of zinc sulfate that we had to add to the water, so that the molarity of the solution would be 0.20 g/mol, we did the following steps: First we calculated the amount of the zinc sulfate to add in moles.