2071 - make up - Recrystallization Thad Tatum

In a test tube, dissolve 10 drops of methanol in 3 ml. of water. Oxidize a copper wire spiral by passing it through a Bunsen burner. Plunge the red-hot wire into the alcohol solution several times, cooling the solution under the tap (faucet) so as not to evaporate too much of it. Next, add 1 drop of 0.5% resorcinol solution. Measure 2 ml. of concentrated sulfuric acid (CAUTION!) and pour this carefully down the sides of the test tube containing the mixture. Note the color of the zone intermediate between the acid and the solution.   RESULT:

4. You'll purify your aspirin product via recrystallization before you can weigh it. The Merck Index indicates that at room temperature, 300 mL of water - but only 5 mL of ethanol - will dissolve 1 gram of aspirin. But the water solubility of aspirin increases with temperature. At 37°C, 1 gram will dissolve in 100 mL of water. Note you'll use a MIXTURE of ethanol and water to recrystallize your aspirin product. a) Why is it essential that you NOT allow the ethanol-water recrystallization mixture to reach a boil? b) And why is it important not to use too large a volume of ethanol in your recrystallization?

Q1. Give three criteria for a good recrystallization solvent. Q2. You want to purify 10 grams of benzoic acid that has been contaminated with 0.2 g of salicylic acid. You are given the following data: Solubility in water at 20 °C Solubility at 100 °C (g/10 ml) Compound (g/10 ml) Benzoic Acid 0.029 0.680 Salicylic Acid 0.680 0.029 0.22 6.67 a) What volume of Boiling water is needed to dissolve the 10 g of benzoic acid? (show calculations) b) How much benzoic acid will crystallize after cooling to 20 °C (show calculations) c) Will any salicylic acid crystals form? Why or why not? (show calculations/ reason for answer) d) What is the maximum amount of benzoic acid that could be recovered in the first crop of this recrystallization? (Show calculations) e) How can you prove the purity and identity of the purified Benzoic acid?

A sample of rainwater was collected from four separate locations across theMetroplex. Each sample was measured once by two separate methods for the presence ofsulfate. Determine whether the two methods are equivalent with respect to giving thesame answer for [SO42-].

A group of third-year students, who had been growing chilli peppers at home, decided to bring samples to their Pharmacology practical where they would be measuring capsaicin, to determine which of them had grown the hottest peppers. The three students ground a sample of their peppers in 100 µl of distilled water, centrifuged the solution and then transferred the supernatant into a collection tube. One student used 70 % ethanol from a wash bottle on their bench instead of using distilled water as the extraction fluid. Samples of the collected supernatants were added to a 96 well test plate along with a range of serially diluted capsaicin standards. The students used a FlexStation which automatically added 20 µl aliquots of each supernatant onto separate wells containing 80 µl of cultured cells, which had been transfected with the capsaicin sensitive TRPV1 ion channel and preloaded with the ratiometric calcium indicator dye FURA-2 prior to the class. The FlexStation was programmed to…

A 20ml mixture contains 10% volume methanol and 90% volume water. Find the mole fraction of water and methanol

Part II. Determination of molecular weight for ethyl alcohol Freezing point, °C DTf   Mass of solute, g mass of solvent, kg Calculated molecular weight, g/mol -2.30 0C ΔTf = T0f – Tf 0.0 °C -(-2.30 °C) = 2.30 0C 6.202 g 0.1kg Click or tap here to enter text.

逐步解决 不使用人工智能出色完成工作 非常感谢您的支持 SOLVE STEP BY STEP IN DIGITAL FORMAT DON'T USE AI | DON'T USE AI | DON'T USE AI | DON'T USE AI | 2. An ethyl alcohol solution that is 75% alcohol by weight is to be used as a bactericide. The solution is to be prepared by adding water to a 95% ethyl alcohol solution. How many grams of each should be used to prepare 400 grams of the bactericide?

Data Sheet 4 ble gives the recommended mass of salt to dissolve in each of the four test tubes. Show a sample calculation for the solubility of KNO, using your actual mass from tube #1. Complete your graph on the back of this sheet. Solution # Recommended mass KNO3 Actual mass of KNO, (g per 5 mL H₂O) Solubility & KNO, 100 g H₂O Saturation temperature (°C) (g) 1 2.0 51.3 2.1971 2 62.5 4.0 11.1568 3 72.7 6.0 6.0112 83.6 4 8.0 806 Sample Solubility Calculation: Questions 1. According to your data, how does the solubility of KNO, change with increasing temperature? Does this indicate an endothermic or exothermic dissolving process? Explain. 2. Using your graph, indicate if each of these solutions would be saturated or unsaturated: a) 110 g of KNO3 in 100 g of water at 40 °C b) 60 g of KNO3 in 100 g of water at 70 °C c) 140 g of KNO3 in 100 g of water at 60 °C 3. According to your graph, what mass of KNO3 will dissolve in 100 g of water at 30 °C?

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In addition to the separation techniques used in this lab (magnetism, evaporation, and filtering), there are other commonly used separation techniques. Some of these techniques are:Distillation – this process is used to separate components that have significantly different boiling points. The solution is heated and the lower boiling point substance is vaporized first. The vapor can be collected and condensed and the component recovered as a pure liquid. If the temperature of the mixture is then raised, the next higher boiling component will come off and be collected. Eventually only non-volatile components will be left in the original solution.Centrifugation – a centrifuge will separate mixtures based on their mass. The mixture is placed in a centrifuge tube which is then spun at a high speed. Heavier components will settle at the bottom of the tube while lighter components will be at the top. This is the technique used to separate red blood cells from blood plasma.Sieving – this is…

You are attempting to purify a compound via recrystallization. You prepare the process through the following method: 1) Dissolve the material in a minimal amount of hot EtOH. 2) Slowly add hot water until the compound is slightly cloudy. 3) Add a small amount of EtOH until the solution is just clear (still hot). 4) Cool to RT. Upon cooling to RT you notice that the compound is not precipitating out of solution. You decide to boil off some ethanol. Upon completing this step and cooling to RT you notice that the compound is precipitating out as desired! In which solvent is your compound the least soluble? Ethanol O Water O The ethanol water mixture Insoluble in all of these solvents

Place 2.4 grams of sulfanilic monohydrate in a 125 ml Erlenmayer flask and dissolve it in 25 ml of 25% aqueous sodium carbonate by boiling. Cool the solution in the flask with running water before adding 0.95 gram of sodium nirite with stirring to dissolve the solid. Pour the solution into a 50 ml Erlenmayer flask containing 12.5 grams of ice and 2.5 ml of concentrated hydrochloric acid. Within a few minutes the white diazonium sulfonate inner salt should form a suspension. Transfer half of it to a 100 ml beaker, and keep both containers cold until each is used in later steps.  Reagents used are ___________ MOA _____________ Product ____________ Visible result ____________

chools.schoology.com/common-assessment-delivery/start/4573067641?action%3Donresume&submissionld%3547892539 150 140 130 120 110 100 NANO 90 80 70 60 NH C Ka Náci 50 40 30 20 KCIÓ, 10 Cez(so 10 20 30 40 50 60 70 80 90 100 Temperature (C) The compound with the least solubility at 50 °C is OKI O NANO3 O KNO3 O NH3 O NH&CI O KCI O NaCI O KCIO3 O Cex(SOa)a DELL & Grams of solute

Part C: Determination of the alcohol content of unknown liquor Stretien Volume (mL) Sample ТИШТИНА 0.00% alcohol 10.0% alcohol 20.0% alcohol 40.0% alcohol 50.0% alcohol Unknown Mass (g) 1o podina ko 9.8919 9.7899 9.600 9 9.420 д % Alcohol content of the liquor_ 9.2155 9.5089 2VLELA CVOLION EAEK EVI OK DRA IVBOKY LOBAN ocen 10.00 10.00 10.00 10.00 10.00 10.00 Density (g/mL) 0.00% alcohol calculation: ися → о 0.99 во 0.99 Ano 7 si dotaW 120.00 supirmbest sdi na LANG 411 be: [scpoidas: 0.97 0.94 in oil to notisalarisi 0.92 0.95

DAY 1 Preparation of Aspirin Using tap water, set up a boiling water bath in a 400ml beaker. Residual solubility. The solubility of acetylsalicylic acid is 0.25 g per 100 ml of water. Keep track of how much DI water is added to the aspirin during filtration and recrystallization. Mix the starting materials and heat. Using the electronic balance, weigh about 2 g (± 0.01 g) of salicylic acid (caution: this is a skin irritant) in a 125 – ml Erlenmeyer flask. Cover the crystals with 4 – 5 ml of acetic anhydride. (caution: acetic anhydride is a severe eye irritant --- avoid skin and eye contact). Swirl this reaction flask to wet the salicylic acid crystals. Add 5 drops of conc H2SO4 to the mixture and gently heat the reaction flask in a hot water bath (60-70oC) for 5 – 10 minutes. (caution: H2SO4 causes severe skin burns). Set up an ice water bath in a 250ml beaker. Cool to crystallize the aspirin. Remove the reaction flask from the hot water bath and add 10 ml of deionized ice…

Calculate the solubility of PbCO3 in water at 25°C . You'll find Ksp data in the ALEKS Data tab. Round your answer to 2  significant digits.

REPORT FOR EXPERIMENT 9 (continued) NAME F. Solubility vs. Temperature; Saturated and Unsaturated Solutions Data Table: Circle the choices which best describe your observations. NaCl 1.0 g +5 mL water 1.0 g +5 mL water +1.4 g dissolved completely? yes/no saturated or unsaturated? dissolved completely? yes/no saturated or unsaturated? 2.4 g +5 mL water +heat dissolved completely? yes/no saturated or unsaturated? 2.4 g +5 mL water after cooling dissolved completely? yes/no saturated or unsaturated? NHC dissolved completely? yes/no saturated or unsaturated? dissolved completely? yes/no saturated or unsaturated? dissolved completely? yes/no saturated or unsaturated? dissolved completely? yes/no saturated or unsaturated? G. Ionic Reactions in Solution 1. Write the word and formula equations representing the chemical reaction that occurred between the barium chloride solution, BaCl,(aq), and the sodium sulfate solution, Na SO (aq). Word Equation: Formula Equation: 2. (a) Which of the…

How does the heat or enthalpy of the reaction (ΔHrxn) change when the concentration of a Strong acid (HCl) is increasing and the concentration of strong base (NaOH) is kept constant in a solution mixture? plz answer showing the steps to solve quantatiavely using hess's law. ive also attached images of my lab data for reference

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