Experiment 6_ Dehydration and GC

You obtain an Unknown Sample from the Stockroom.  You begin testing the solution through the steps outlined in the flowchart of the experiment’s PDF file.  You first add HCl and centrifuge your mixture.  You observe the formation of a white precipitate in the bottom of the test tube.   After pouring off the supernatant liquid, you add hot water to the white precipitate.  Addition of the hot water dissolves some of the precipitate, but some white precipitate still remains on the bottom of the test tube.   Which of the following is a valid conclusion to draw at this point?     Pb2+ is definitely present.   Hg22+ is definitely present.   Ag+ could be present, or Hg22+ could be present, or BOTH could be present.   Ag+ is definitely present

You obtain an Unknown Sample from the Stockroom.  You begin testing the solution through the steps outlined in the flowchart of the experiment’s PDF file.  You first add HCl and centrifuge your mixture.  You observe the formation of a white precipitate in the bottom of the test tube.   After pouring off the supernatant liquid, you add hot water to the white precipitate.  Addition of the hot water dissolves some of the precipitate, but some white precipitate still remains on the bottom of the test tube.  You pour off the supernatant liquid, and add ammonia (NH3) to the remaining precipitate.  You now observe the formation of a gray-black precipitate. Which of the following is a valid conclusion to draw at this point? Select one:     Hg22+ is definitely present.   Pb2+ is definitely present.   Ag+ could be present, or Hg22+ could be present, or BOTH could be present.   Ag+ is definitely present

You obtain an Unknown Sample from the Stockroom.  You begin testing the solution through the steps outlined in the flowchart of the experiment’s PDF file.  You first add HCl and centrifuge your mixture.  You observe the formation of a white precipitate in the bottom of the test tube.   After pouring off the supernatant liquid, you add hot water to the white precipitate.  Upon addition of the hot water, you have some white precipitate still at the bottom of the test tube, and the supernatant liquid is poured off.  To this liquid, potassium chromate (K2CrO4) is added.  Upon this addition of potassium chromate, you observe no formation of precipitate. Which of the following is a valid conclusion to draw at this point? (Choose one.)   Select one:   1. Hg22+ is definitely present.   2. Pb2+ is NOT present. 3. Ag+ is definitely present. 4. Pb2+ is definitely present.

Consider the following scenario: You obtain an Unknown Sample from the Stockroom.  You begin testing the solution through the steps outlined in the flowchart of the experiment’s PDF file.  You first add HCl and centrifuge your mixture.  You observe the formation of a white precipitate in the bottom of the test tube.   After pouring off the supernatant liquid, you add hot water to the white precipitate.  Addition of the hot water dissolves some of the precipitate, but some white precipitate still remains on the bottom of the test tube.  You pour off the supernatant liquid, and add ammonia (NH3) to the remaining precipitate.  You now observe the formation of a gray-black precipitate. Which of the following is a valid conclusion to draw at this point? Select one:   1. Hg22+ is definitely present.   2. Pb2+ is definitely present.   3. Ag+ could be present, or Hg22+ could be present, or BOTH could be present. 4. Ag+ is definitely present

Please help

You were tasked to separate the components of a mixture containing silica, sodium chloride and charcoal. TNāCI dissolves in water while silica and charcoal are not water-soluble. Only charcoal dissolves in carbon disulfide. a. Write a short experimental procedure to carry out the separation of the mixture. b. Given the following data, determine the percentage of charcoal, sodium chloride and silica. Mass (g) Mass of beaker 100.000 Mass of beaker + mixture 110.000 mass of evaporating dish 62.000 mass of evaporating dish + solid after evaporation of water 65.000 Mass of beaker + charcoal + silica after evaporation of excess water 117.000 mass of beaker + silica after decanting dissolved charcoal and drying 113.545

Why is fractional distillation more efficient than simple distillation when purifying liquid mixtures?

please highlight the correct answer

Using recrystallization techniques, a student attempts to purify 0.50 g of compound H. Based on the solubility of H in the chosen solvent at collection temperature, the maximum percent recovery is 82%. The student obtains 0.396 g of purified crystals. What is their percent recovery? Group of answer choices 41% 64% 79% 82% 97% none of these

5.0 mL of 1-butanol was mixed with 10 mL of HCl. The reaction was put on an ice bath and 4 mL of concentrated sulfuric acid was added. This mixture was refluxed for 45 min and then the product was co-distilled with water using a simple distillation apparatus. Water and the product are immiscible. 1-butanol has a molar mass of 74.12 g/mol, a density of 0.810 g/mL, and a boiling point of 118 C. The product has a molar mass of 92.57 g/mol, a density of 0.880 g/mL, and a boiling point of 78 C. What is the nucleophile in this reaction? What is the role of H2SO4 in this reaction? Calculate the theoretical yield for this reaction. Give your answer in grams.  Select the following statements that can be said about the reaction shown.

Can I get detailed explanation for this table , mentioning the apparatus and when’s the timer is started ? What happens next

List and describe two methods that can used to improve the separation of a liquid mixture by fractional distillation

Line equation?

Part C Fe(NO3)(aq) and HCl(aq) Express your answer as a balanced net ionic equation. Identify all of the phases in your answer. Write "NR" if no reaction occurs. ΑΣφ 四-? Submit Request Answer Part D HNO3 (ag) and Bi(OH)3(s) Express your answer as a balanced net ionic equation. Identify all of the phases in your answer. Write "N.R." if no reaction occurs. ΑΣφ A chemical reaction does not occur for this question. Submit Request Answer

Oral rehydration salts are stated to contain the following components:   Sodium Chloride 3.5g   Potassium Chloride 1.5g   Sodium Citrate 2.9g   Anhydrous Glucose 20.0g   8.342 g of oral rehydration salts are dissolved in 500 ml of water. 5 ml of the solution is diluted to 100 ml and then 5 ml is taken from the diluted sample and is diluted to 100 ml. The sodium content of the sample is then determined by flame photometry. The sodium salts used to prepare the mixture were:   Trisodium citrate hydrate (C6H5Na3O7, 2H2O) MW 294.1 and sodium chloride (NaCl) NW 58.5.   Atomic weight of Na = 23.   The content of Na in the diluted sample was determined to be 0.3210 mg/100 ml. Determine the % of stated content of Na in the sample. The stated should be 104.5, how??

Q15 and Q16 and Q17 please

Graph data with Concentration on the x-axis and Absorbance on the y-axis. Find the line of best fit for your data points. Record the respective formula in y=mx+b.

What is the purity test of synthesized aspirin and commercial aspirin?

3) Propagation of uncertainty. Every measurement has uncertainty. In this problem, we'll evaluate the uncertainty in every step of a titration of potassium hydrogen phthalate (a common acid used in titrations, abbreviated KHP, formula CsH5KO4) with NaOH of an unknown concentration. The calculation that ultimately needs to be carried out is: concentration NaOH 1000 x mass KHP × purity KHP molar mass KHP x volume NaOH Measurements: a) You use a balance to weigh 0.3992 g of KHP. The uncertainty is ±0.15 mg (0.00015 g). b) You use a buret to slowly add NaOH to the KHP until it reaches the endpoint. It takes 18.73 mL of NaOH. The uncertainty of the burst is 0.03 mL.. c) The manufacturer states the purity of KHP is 100%±0.05%. d) Even though we don't think much about them, molar masses have uncertainty as well. The uncertainty comes from the distribution of isotopes, rather than random measurement error. The uncertainty in the elements composing KHP are: a. Carbon: b. Hydrogen: ±0.0008…

A. Calculate the solubility of PbI2  (Ksp = 1.5 x 10-8) in moles per liter. Ignore any acid–base properties. B. Calculate the solubility of CdCO3 (Ksp = 5.1 x 10-12) in moles per liter. Ignore any acid–base properties. C. Calculate the solubility of Sr3(PO4)2 (Ksp = 1.5 x 10-31) in moles per liter. Ignore any acid–base properties.