Professional photographers most commonly use digital photography now. However, some photographers still prefer the quality of the image and the developing process of black and white film compared to digital images. A photographic stop bath is a chemical bath used in processing black and white film. When developing black and white film, a basic developing solution is used to have the pictures develop from the film. The stop bath solution is a dilute 1 to 2% acetic acid solution, and it is applied to the film to stop immediately the development of the film. If the electrical conductivity of the stop bath solution was tested, what degree of electrical conductivity would be expected? Explain MAMUT

Professional photographers most commonly use digital photography now. However, some photographers still prefer the quality of the image and the developing process of black and white film compared to digital images. A photographic stop bath is a chemical bath used in processing black and white film. When developing black and white film, a basic developing solution is used to have the pictures develop from the film. The stop bath solution is a dilute 1 to 2% acetic acid solution, and it is applied to the film to stop immediately the development of the film. If the electrical conductivity of the stop bath solution was tested, what degree of electrical conductivity would be expected? Explain MAMUT

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter8: Sampling, Standardization, And Calibration

Section: Chapter Questions

Problem 8.1QAP

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Because of the risk of lead poisoning, the exposure of children to lead-based paint is a significant public health concern. Thefirst step in the quantitative analysis of lead in dried paint chips is to dissolve the sample. Corl evaluated several dissolution techniques.24 In this study, samples of paint were collected and pulverized with a Pyrex mortar and pestle. Replicate portions of the powdered paint were then taken foranalysis. Results for an unknown paint sample and for a standard reference material, in which dissolution wasaccomplished by a 4–6-h digestion with HNO3 on a hot plate, are shown in the following table. (a) Determine the overall variance, the variance due to the method, and the variance due to sampling. (b) What percentage of the overall variance is due to sampling? (c) How might the variance due to sampling be decreased?
You want to make a solution of the primary standard sodium oxalate. It has a molecular mass of 133.999 g/mol (no error). Your analytical balance has an error of 0.2 mg. You add some weighing paper to the balance and it reads a mass of 0.23626 g. You then add sodium oxalate onto the weighing paper until the mass registers as 2.8539 g. You carefully transfer this to a 250.0 ml volumetric flask with an error of 0.1 ml and dissolve the sodium oxalate in a sufficient volume of water. What is the concentration of the oxalic acid (in M) and what is the absolute error (also in M).
You are preparing a 100.0 mL standard solution needed for titration analysis. The NaOH (40 g/mol) pellets are measured to be 0.5341 g in a balance with acceptable uncertainty of +0.001 g. Mass of the pellets is recorded after taring the container. The pellets are put in a beaker and added with 50 ml distilled water measured by a graduated cylinder. The solution is then quantitatively transferred to a 100-mL volumetric flask with uncertainty of ±0.08 mL and diluted to a 100-mL mark. What is the concentration (M) of the solution and estimate its uncertainty by propagation? Assumption: There is no uncertainty in molar mass. Express your answer as C+/- u M.
Ammonium sulfate is added to an unknown mixture of ions. A precipitate forms. The solution is centrifuged, and the remaining solutions is decanted. Ammonium oxalate is then added to the solution and no precipitate forms. Sodium monohydrogen phosphate and sodium hydroxide are added to the decanted solution, and no precipitate forms. Sodium hydroxide is added to a fresh sample of the unknown. A damp piece of litmus paper over the opening of the test tube remains red. Select the ions present. Question 5 options: Ba2+ Ca2+ Mg2+ NH41+
Ammonium sulfate is added to an unknown mixture of ions. A precipitate forms. The solution is centrifuged, and the remaining solutions is decanted. Ammonium oxalate is then added to the solution and no precipitate forms. Sodium monohydrogen phosphate and sodium hydroxide are added to the decanted solution, and no precipitate forms. Sodium hydroxide is added to a fresh sample of the unknown. A damp piece of litmus paper over the opening of the test tube turns blue. Select the ions present. Question 4 options: Ba2+ Ca2+ Mg2+ NH41+
Procedure: Step 1: Pipet 25 mL of prepared sample solution, which has been prepared into a 250 mL Erlenmeyer flask. Step 2: Add 3-5 drops of phenolphthalein indicator solution to the sample solution in the 250 mL Erlenmeyer flask. Step 3: Rinse the buret with three 10 mL portions of standardized 0.1 M HC1 acid solution, before fill this acid solution into the buret and record the initial volume of this acid solution in the burette. Step 4: Titrate the sample solution with the standardized 0.1 M HC1 to the endpoint and record the final volume of this acid in the burette. (Note: phenolphthalein endpoint is from pink color to colorless) Step 5: Repeat the titration for two more times. Step 6: Repeat the same procedure from step 1 to step 5 by using methyl orange as an indicator rather than phenolphathelein. (Note: methyl orange endpoint is from orange to red color). Calculate the alkalinity of the sample for both the indicators and potentiometric method using the following equation: [Alk]…
A water sample was analyzed for iron content using the iron-phenanthroline method. Using the set of data from Question 15 (as presented below), Reagent Blank Absorbance Absorbance (au) Reagent Blank Absorbance 0.003 Concentration of Stock Solution: 10 ppm Volume of Stock Solution (mL) Total Volume of Standard Solution (mL) 0.50 10.00 1.00 10.00 2.00 10.00 3.00 10.00 4.00 10.00 5.00 10.00 Volume of Trial Unknown Solution (mL) 1 5.00 2 5.00 3 5.00 find the true concentration of Fe2+ of the original sample. A) 5.12 ppm B) 2.56 ppm 2.52 ppm D) 5.05 ppm Concentration of Standard Solution (ppm) Total Volume of Unknown Solution (mL) 10.00 10.00 10.00 Absorbance (au) 0.012 0.132 0.267 0.349 0.428 0.560 Absorbance (au) 0.289 0.296 0.281
A water sample was analyzed for the total hardness through the reaction between the sample and EDTA. The data obtained from the experiment are presented below (MM CaCO3 = 100.0869 g/mol): Table 1. Standrdization of the EDTA solution mass of CaCO3 used 0.4567 g Initial burette reading 8.20 mL Final burette reading 15.65 mL Volume consumed 7.45 mL Table 2. Determination of Hardness of Water Volume of water sample 50.00 mL Initial burette reading 15.65 mL Final burette reading 24.85 mL Volume consumed 9.20 mL O 12,390 ppm O 990 ppm O 11,270 ppm O 10,290 ppm
0.3414 grams of sample (crushed aspirin tablet) was weighed and dissolved in 25 mL ethanol. This solution was transferred into a 100 mL volumetric flask and filled to the mark with deionized water. 20 mL of the solution was filtered through a 0.22 μm pore filter and 503 μL of the filtered sample solution was diluted so, that the final volume of the solution was 12 mL. This sample solution and calibration solutions with known concentration of acetyl salicylic acid (ASA) were injected (injection volume 20 μL) into a HPLC and the following peak areas were measured (expressed as averages from three separate chromatographic runs): Solution Cal 1 Cal 2 Cal 3 Cal 4 Cal 5 Sample Structure of ASA: C(ASA) (mg/L) 0 OH B 53.5 105.9 140.9 195.4 247.4 Average weight of the tablet was estimated as 591.9 mg. What is the mass of ASA in one tablet? Please give the answer with 4 significant digits. Be sure you present the result with units! Peak area (mA.s) 4995 9953 12941 17271 22179 10467.3
A student determined fluoride in a toothpaste sample using ion chromatography. A toothpaste sample of mass 0.100 g was dissolved in type I water and then quantitatively filtered through a Whatman #1 filter paper into a clean 100 ml volumetric flask. The flask was then made up to volume with type I water and mixed thoroughly.A portion of the solution was filtered through a 0.45 um filter into a sample vial for analysis. Analysis of the sample gave a fluoride concentration of 1.60 mg/l Calculate the % w/w fluoride in the original toothpaste sample. (Give your answer to 3 decimal places please)
ASSAY Calibration solutions Calibration solutions of naproxen in the range 5 – 25 μg/mL were prepared. Sample preparation 20 tablets weighing 12.3819 g were crushed to a fine powder. A portion of the powder (145.4 mg) was shaken with approximately 150 mL of acetic acid (0.05 M) for 5 min and then made up to volume in a 250 mL volumetric flask (stock solution). Approximately 50 mL of the stock solution was filtered and a 25 mL aliquot was diluted to 100 mL in a volumetric flask. 10 mL of the resulting solution was further diluted to 100 mL with acetic acid (0.05 M). Analysis The standards and sample solutions were analyzed by HPLC under the following conditions: Column: octadecylsilyl (ODS), 4.6 mmx150 mm, mobile phase: acetonitrile : 0.05 M acetic acid (85:15), flow rate: 1 ml/min, UV detection at 243 nm. Results: A calibration curve of concentration versus peak area was constructed for the standard solutions and gave the straight-line equation: y = 3555.6x + 85, r = 0.9999 The area…
Six clean, dry, 18 x 150mm test tubes 1-6 was labeled. 5.00 L of 2.00 x 10-3 M Fe(NO3)3 solution was pipeted in each tubes. Then 1.00,2.00,3.00,4.00, and 5.00 mL of 2.00 x 10-3 M of 2.00 x 10-3 M NaSCN solution was then added to test tubes 2-6 respectively. 5.00, 4.00 ,3.00,2.00 and 1.00 mL of 0.10 M HNO3 was then further added to test tubes 1-6 respectively. The total volume in each test tube is 10 mL. a) what is the concentration of Fe(NO3)3 in 0.10 M HNO3? b) what is the concentration of NaSCN in 0.10 M HNO3 solution?