Lab Summary

Why should curd and sour substance not be kept in brass and copper vessels.

A solution is made by the following steps. 1. 90.0 mg ± 0.2 mg of dye with molar mass 685.79 g/mol ± 0.02 g/mol is dissolved in a 100.00 mL ± 0.05 mL volumetric flask with water to make solution #1. 2. 25.00 mL of solution 1 is added 100.00 mL ± 0.05 mL volumetric flask with water to make solution #2. 3. 25.00 mL of solution 2 is added 100.00 mL ± 0.05 mL volumetric flask with water to make solution #3. A.) If you have available a 5.00 mL ± 0.01 mL, 10.00 mL ± 0.05 mL, and 25.00 mL± 0.15 mL. Describe how to use the pipettes and the directions above to make the most precise solution #3. Explain why this is the most precise method. B.) Determine the concentration ± absolute error of solution #3 in molarity. Explain the calculations you needed to do. C.) Using Beer's law (10% error), solution #3 is found to be 2.0 ✕ 10-5 M. Was solution #3 likely made within the expected error. Explain.

You're at the same pharmaceutical company, and they also make magnesium pills. You weigh out 5 tablets (3.2834 grams). And crush them with a mortar and pestle. You take a subsample of 384 mg and dissolve it in acid, making it to a final volume of 250mL. • You then take 50 mL and dilute it to 250mL volumetrically. • You further dilute the sample by taking 15 ml and diluting it to 250mL. • You run this on a varian AA with your standards and get the following response: Response (ABS) 0.546 1.134 2.135 1.634 ● ● Solution 1.0 ppm Mg 2.0 ppm Mg 4.0 ppm Mg Sample Calculate the amount of Mg in one pill. Line of best fit y = 0.5255x+0.0455

Describe how to prepare a 20.00-µg/mL iron solution from a 1000-mg/mL iron standard solution using 10-mL and 50-mL volumetric pipets and 500-mL and 1000-mL volumetric flasks.

Series 9. Mixtures Brass Sand + CuSO4• 5H2O White wine Series 9. Mixtures (continued) Water and BaSO4 Oil and water Vinegar

_4. Preservatives that are usually found in cured meats, bacon, ham, corned beef and hot dogs. A. Benzoates C. Sorbates В. Nitrates D. Acids 5. A type of additive that stabilizes foods through moisture control. A. Emulsifiers C. Humectants B. Flavor Enhancer D. Antioxidants 6. Additives that are usually powders added to baking mixtures which react chemically to release carbon dioxide. A. Raising Agents B. Thickeners C. Humectants D. Antioxidants

Write your complete solutions on yellow paper, round your answers to the appropriate number of significant figures, and box the final answer. The deadline for submission is at the end of the class. Note: You do not need to write your solutions for the items that can be derived from your calculators. 1. Three students (Saerom, Hayoung, and Jiwon) are asked to determine the ppm Ca in a drinking water sample by titration with EDTA. Each student performed five trials for the sample. The results in ppm Ca are the following: Saerom Hayoung Jiwon a. Get the mean, SD, and % RSD of each student's results. b. If the true value is 35 ppm, calculate the relative error of each student's results. c. Comment on the precision and accuracy of each student's results. The maximum % RSD and the relative error set by the lab is 5.0%. d. Use the following table to summarize your answers. Mean SD %RSD Relative Error Comment 31, 32, 33, 33, 32 35, 34, 34, 35, 34 35, 38, 33, 35, 37 Saerom Mean SD 95% CI…

Which of the following methods is used to determine "dissolved metals" in a water sample? O Digest the water sample and measure the metals in the digest Filter the water sample and measure the metals in the filtrate Filter the water sample and measure the metals in the particles in the filter Digest the water sample, filter the digest, then measure the metals in the filtrate

Please help me look for OINTMENTS that have precipitated sulfur as an active ingredient. I need the names of the products available today.

1. A stock solution of I2 is standardized using a 0.1430 g sample of pure ascorbic acid. The titration to the starch endpoint required 25.45 mL of the I2 solution. Calculate the molarity of the I2 solution. 2. A vitamin C tablet was divided into three equal mass portions. One portion was crushed into a fine powder, dissolved in water, and titrated with the standardized solution from question 2 (above). The titration to the endpoint required 27.60 mL of the I2 solution. Calculate the number of milligrams of vitamin C that are in the original tablet.

Dilute the stock solution: Using the solutions in the burets, carefully measure the following quantities of Co(NO3)2 solution and water into 5 large test tubes, to a total of 5.00 mL in each test tube. Yes, the optional video says to make 10.00 mL total, but 5.00 mL is sufficient at this time and generates less waste. Use the buret to measure the cobalt solution and the water. Test tube No. 1 2 3 4 5 mL Co2+ Soln 1.00 2.00 3.00 4.00 5.00 mL H2O 4.00 3.00 2.00 1.00 0.00 Total mL 5.00 5.00 5.00 5.00 5.00   Mix each test tube thoroughly: hold the top of the tube and mix the bottom well. Transfer a portion of each diluted sample into a clean, dry sample cuvette.  fill the concentration table and do calculations please

A Mn2* substock solution was prepared by pipetting 6.00 mL of the stock solution into a 200.00 mL volumetric flask, and diluting to the mark with 0.18 M HNO3. Calculate the concentration of the Mn2 substock solution in ppm O 6.10 ppm 1.52 ppm 24.4 ppm 75.0 ppm 14.4 ppm Messages

4. Calcium in a 200-ul serum sample is titrated with 1.87 x 10-4 M EDTA solution, requiring 2.74 mL. What is the calcium concentration in the blood sample in mg/dL?

Q4 | What is the purpose of conducting the recrystalization process of the product ?

O Macmillan Learning A chemist needs to create a series of standard Cu² +(aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 25.00 mL of a 2.71 M Cu²+(aq) stock solution to a 500.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 20.00 mL of the second solution to a 100.0 mL volumetric flask, and he adds enough water to dilute to the mark. Calculate the concentration of the Cu² (aq) solution in the 100.0 mL volumetric flask. concentration: M

Which of the statements given below is correct? A. Iodometry is a method in which 12 solution is used as a titrant and the substances that can reduce iodine to iodine can be determined. B. Starch indicator is added to the medium at the beginning of the titration. C. All metal salts other than alkali salts dissolved in water cause hardness properties. D. 1 German hardness is the hardness of water containing cation equivalent to 1 mg CaCO3 per 100 mL.

A solution is made by the following steps.  1.) 90.0 mg ± 0.2 mg of dye with molar mass 685.79 g/mol ± 0.02 g/mol is dissolved in a 100.00 mL ± 0.05 mL volumetric flask with water to make solution #1.  2.) 25.00 mL of solution 1 is added 100.00 mL ± 0.05 mL volumetric flask with water to make solution #2.  3.) 25.00 mL of solution 2 is added 100.00 mL ± 0.05 mL volumetric flask with water to make solution #3.  Describe how to use the pipettes and the directions above to make the most precise solution #3. Explain why this is the most precise method.

Part A Consider the following reaction: Enter the complete ionic equation for this reaction. Express your answer as a complete ionic equation. Identify all of the phases in your answer. ΑΣΦ A chemical reaction does not occur for this question. Submit Request Answer Part B Complete previous part(s) Provide Feedback ? 2HI(aq) + Ba(OH)2 (aq) → 2H₂O(1) + Bal₂(aq)

A student determined the concentration of copper by ion exchange. He obtained the following results: (4.2180x10^1) mL of (9.64x10^-2) M NaOH solution was required to titrate the eluate (HCI solution) from the column. He used a 15.0 mL sample of copper chloride solution initially. Calculate the concentration of Cu*2 in the original solution. Your answer should be in correct scientific notation (that is what the red text in BrightSpace means.) Note: Your answer is assumed to be reduced to the highest power possible. Your Answer: |x10 Answer

A stock solution whose concentration is 25.00 mg/mL was provided. A primary standard solution was then prepared by transferring 5.00 mL of the stock solution into a 50.00 mL volumetric flask. The primary standard solution was used to prepare three standard solutions of different concentrations by taking different volumes of aliquots into three 25.00 mL volumetric flasks: Standard Solution #1 #2 #3 Amount of Primary Solution (mL) 5.00 10.00 15.00 Three 25.00 mL volumetric flasks were then diluted to mark with water. Questions #1 What is the concentration of the primary standard solutions, expressed in units of mg/ml? #2 Re-write the concentration of the primary standard solutions obtained from Q#1 in units of μg/mL. #3 Determine the concentrations of three standard solutions in units of µg/mL. #4 What is a requirement for a "blank" solution used in calibration in spectrophotometry? Page 5 (Experiment #3)

A student performed an acid-base titration in the lab and recorded the results as shown below. Look very carefully at the results and answer the questions which follow. 7. 演定結果 21 3. 346 27.40 00 36 終結摘定管讀數(cm) 開始定管數(Cm 所需演定州的積(cm) 44 標 (a) Why do we perform acid-base titrations in our labs? (b) In the titration performed by the student, what was the net ionic equation for the chemical reaction occurring?

A student needs 50.0 mL of 5.74×10 -4 M FD&C Blue Dye No. 1 solution. If the student has 2.00 mM FD&C Blue Dye No. 1 stock solution to work with, how much of the 2.00 mM solution should be added to the 50.0 mL volumetric flask? Hint, 2.00 mM is 0.00200 M.     14.35 mL     0.06971 mL     3.485 mL     12.85 mL     6.971 mL

Ba(NO3)2 + Na2CO3 → Mg(NO3)2 + K2CRO4 → Ca(NO3)2 + K2CrO4 → Sr(NO3)2 + K2CrO4→ -> Ba(NO3)2 + K2CRO4→

A chemist was asked to determine the molecular weight of Compound J.  They created a solution with 20 percentage w/w concentration from solid Compound J, with a density of 1.40 g/mL. From this solution, a 10 μL aliquot was taken and mixed with 190μL of reagent and water. This was then analyzed and had 5.0 e-4 M compound J. What is the concentration in molarity of the 20% w/w solution? How do you determine the molecular weight of said compound?

It takes 91 mm2 of overall surface area, in the form of a calcium-based substrate sheet, (CaCO3 density=D2.7 g/cm³) to neutralize acidic runoff coming from a factory. How much CaCO3, in mg/ml, does it take to neutralize this acid water?

5) Define, classify and briefly describe what is detergent.

A solution is contaminated with traces of copper, nickel, and zinc. Which option would be the safest way to make it safer for human consumption? Ksp OH co,?- s2- Cu2+ 4.8x10-20 2.3x10-10 бх10-37 Ni2+ 6.0x10-16 1.3x10-7 Зx10-20 Zn2+ 3.0x10-16 1.0x10-10 2x10-25 raise the pH to about 12 bubble CO2 into the solution lower the pH about 2 increase the sulfide level

1. Copper metal and aqueous iron (III) chloride were made to react to reduce iron to Fe²+ while oxidizing copper to Cu²+. What mass (in g) of copper metal is needed to react with 50 mL of 20.5 wt.% iron (III) chloride (solution density is 2.9 g/mL)?

You were assigned to assay a product sample of milk of magnesia. A 0.600-g sample was reacted with 25.00 mL 0.10590 N H2SO4 . The excess unreacted acid in the solution required 13.00 mL of 0.09500 N NaOH when titrated to reach the methyl red end point. Determine the dosage strength of the product in terms of % Mg(OH)2 content. Type your answer in 2 decimal places, numbers only.

A colored solution of concentration 0.0344 mol/L has an absorbance of 0.481. What is the concentration a solution of the same solute with an absorbance of 0.651? Assume that the same sample celf is used for both readings. Report your answer to 3 significant figures.

If the copper standard solution has a concentration of 25 μg/mL, what is the concentration of a prepared solution with 4 mL of the standard solution with 2 mL 10% hydroxylamine hydrochloride, 5 mL 10% ammonium acetate, and 5 mL of 0.1% bathocuproine prepared in a 25 mL volumetric flask?

In a few lines, describe the IMMENENT IMPORTANCE of “Green Chemistry" and its importance to Society.