is a method of purifying a compound by removing any 31. impurities that might be mixed with it. It is often used as a final clean-up step, after other methods that are effective at removing larger amounts of impurities, but that do not raise the purity of the final compound to a sufficiently high level. * Sublimation Recrystallization O Decolorization

is a method of purifying a compound by removing any 31. impurities that might be mixed with it. It is often used as a final clean-up step, after other methods that are effective at removing larger amounts of impurities, but that do not raise the purity of the final compound to a sufficiently high level. * Sublimation Recrystallization O Decolorization

Introductory Chemistry: An Active Learning Approach

6th Edition

ISBN:9781305079250

Author:Mark S. Cracolice, Ed Peters

Publisher:Mark S. Cracolice, Ed Peters

Chapter16: Solutions

Section: Chapter Questions

Problem 16.3TC

See similar textbooks

Similar questions

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?
2. An impure sample of compound D is contaminated with a number of impurities. The sample is to be purified by recrystallization. The solubility properties of three potential solvents are summarized below. Choose the best solvent and explain your answer. Include comments on each of the three solvents. Solubility of D at the boiling point Solubility of D at - 0°C of the solvent Solvent X 0.08g/mL 0.06 g/mL Solvent Y 0.67 g/mL 0.59 g/mL Solvent Z 0.63 g/mL 0.12 g/mL
During dilution process, what do you do if you add a bit too much solvent when filling the volumetric flask to the mark? O Calculate the equivalent amount of salt and add that to the solution O Remove the excess content of the flask until the volume matches the calibration mark O Start over, the solution cannot be saved OUse a distillation unit to evaporate the excess solvent
750 g Oral Saturated Solution 237 mL per Potassium iodide 950 g elemental iodine + 1.5 kgs potassium hydroxide potassium iodide 1 g per mL bottle IC. SYNTHESIS AND PACKAGING Balanced Chemical Reaction % composition by mass of each compound Mass to Mass Stoichiometry Calculation Limiting Reagent Excess Reagent Amount (g) in excess % Yield Number of dosage form and packaging that can be produced from stoichiometric calculation
Which of the following statements is true? A Liquids can be weighed using a weighing paper. B In weighing hygroscopic substances, containers should always be kept close when not in use. CAfter drying a sample in the oven, you can place it immediately inside the analytical balance. D Place solid reagents / precipitates directly on top of the balance pan.
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)
Explain and answer properly in recrystallization, after the crystals have formed (with cooling on standing), the solution can be cool with ice. why is this done ? a) To get the impurities to crystallize as well b) Less product is needed to saturate cold solvent so the yeild is higher c) The impurities are more soluble in cold solvent
_refers to the formation of a new, insoluble product by a chemical reaction; this product then precipitates out of the reaction 51. solution as an amorphous solid containing many trapped impurities. * Sublimation Crystallization Recrystallization O other:
A bbhosted.cuny.edu/webapps/assessment/take/take.jsp?course_assessment_id=_1... R Paused E Apps G Gmail O YouTube O Maps Home Take Test: Test #1 * Question Completion Status: A MOving to the next question prevents cnanges to tnis answer. Question 4 of 20 > Question 4 4 points Save Answer What is the density of a solid sample that increased the volume of 25.2 mL of water to 34.9 mL when placed in the graduated cylinder and weighs 13.34 g? O A. 0.52 g/mL O B. 0.38 g/mL OC. 1.37 g/mL O D.0.73 g/mL A Moving to the next question prevents changes to this answer. Question 4 of 20 13,846 MAR étv S esc F2 F3 F4 F5 F6 F7 @ %23 24 2 & Q W E R Y II
PAPER CROMATOGRAPHY • Define chromatography • Demonstrate an understanding of the process of chromatography • Describe the steps involved in a chromatography investigation Explanation Coloured inks are often made up of several different inks. Each colour of ink will get carried a different distance by the water, allowing you to see all of the different inks. Try this with different colours to see what actually goes into a colour. This technique is called chromatography and can be used in chemistry to find out what is in an unknown mixture. II. Materials .Felt tip pens (non-washable) . Kitchen roll .A bowl or cup . Water • Scissors III. Health and safety • Make sure that you thoroughly clean any equipment after the experiment before using for food IV. Procedure Method 1 1. Take a sheet of kitchen roll and draw a simple picture with a non-washable felt tip pen. 2. Place the sheet over an empty bowl. This is to keep the paper from getting too wet. 3. Carefully add a few drops of water…
The student dissolved 1.056 g of the given powder mixture (barium chloride + magnesium chloride) in water in a conical flask and added an excess of sulfuric acid. The mass of this white solid precipitate formed was 0.764 g, after filtering off, washing and drying it. a) Calculatethepercentage,bymass,ofmagnesiumchlorideinthepowder. (show all your calculations, units and significant figures are important)
A K2SO4 solution is prepared by weighing out a certain amount of the pure solid reagent,dissolving it to 500.0 mL in a volumetric flask. An aliquot was taken from this solution.of 25.00 ml and diluted to 500.0 ml. An aliquot of 5.00 was taken from this new solution anddiluted to 50.00 ml. A chemical analysis of this new solution showed a 0.100%(w/v)in K+. Calculate the weight of the pure solid K2SO4 used for the preparation of the original solution.and its concentration in each volumetric flask. The answer is 2.23x10^2g