ELN Vacuum filtration.docx

blue ink from three different pens appears to be the exact same color. explain how to determine whether the dyes are identical

An oil sample had its iodine number determined using the pyridinium tribromide method. The sample and reagents used are as follows: Oil sample: 0.19 mL, density: 0.954 g/mL Pyridinium tribromide: 0.472 g Na2S203: 0.1 M, endpoint 27.68 mL %3D What is the approximate Bromine Number? O 138 89 O 120 O 200

You wash a separatory funnel with soap and water to ensure it is clean before extracting an aqueous solution with dicholormethane. You should take the time to make sure there are no drops of water left inside the separatory funnel. Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a True False

1.Toxicity Characteristic Leaching Procedure (TCLP) 2.Effect within minutes or days after exposure 3.Colorless gas used for the production of methanol 4. Mesothelioma 5. Combustion product that is associated with burning tire smell 6. Oral lethal dose in grams of a chemical with an LD50 of 1500 mg/kg for a 105 kg person 7. Effect several years after exposure 8. Product causes long-term chronic effects 9. Toxic pollutant that is associated with atmospheric haze 10. Federal drinking water standard for lead Match with the following answer .    a)157.5 g, b) Carbon monoxide c) Sulfur dioxide d) CPSC Toxicity Criteria e) Chrysotile f) RCRA Toxicity g) 15 µg/L h) Acute health effect i) 71.6 g j) Latent health effect k) Nitrogen oxide

Color BEFORE adding Color AFTER adding Intensity of color AFTER adding FeCl3 Test Tube # FeCl3 FeCl3 #1 (salicylic acid) clear lilac 100% #2 (commercial aspirin A) clear slightly pink 50% #3 (commercial aspirin B) clear lilac 95% #4 (aspirin from your clear pink 20% synthesis above) #5 (control) clear clear 0% Based on this data and the melting point of Aspirin, how pure is the synthesized product?

PART ONE: Preparation of FECNS* Solution Prepare the two solutions in table 1 by accurately measuring the required volumes of distilled water and CNS into two labeled test tubes. The absorbance of the solutions must be measured soon after adding the Fe" solution from a buret. TABLE 1 Fe 5 ml 5S mL Solution Distilled Water CNS 2 mL Total Volume 3 ml 2 ml 10 ml 3 mL 10 ml In this part of the experiment you are to explore what the above quote means. As a PRELIMINARY Exercise, formulate a hypothesis as to what would happen under each of the following circumstances: 1. 1ml of 0.0020 M CNS' solution is added to the unused portion of solution 1 in the test tube 2. One drop of 0.20 M CNS solution is added to the unused portion of solution 2 in the test tube.

Is there any difference between post-processing and post-treatment?

Calculate the volume of NaOH used in each trial. Use sig figs.

If an analytical method relies on a measurable property of an analyte that can be correlated with the amount of the said analyte, what type of analytical method is it?   Oxidative methods   Instrumental methods   Blank Correction methods   Classical methods

Table 1. Data on EDTA Standardization Weight of CaCO3 (g): 0.2003g Trial Volume of EDTA (mL) Molarity of EDTA (M) 1 8.60 2 8.50 8.55 Average Molarity of EDTA (M)

. Given the following drugs in a urine specimen: Cocaine alkaloid Secobarbital (a derivative of barbituric acid) Carisoprodol (a neutral drug)      Devise an analytical flow chart that will be used to separate these substances from a urine specimen. The separation will be liquid extraction methods. Choose appropriate solvents and reagents based on the properties of the materials to be separated.

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10.0456g of butter are analyzed using our procedure and the titrant above. The burette volumes were 0.57 mL and 28.96 mL. Calculate the % NaCl of the butter. Keep in mind the butter is extracted with 250 mL of Water and only 20 mL is titrated.

19. What is thin layer chromatography (TLC) LEAST useful for from the list below? A) To determine if crystallization or distillation may be more effective for a separation B) To determine the number of components in a mixture C) To determine the appropriate solvent for column- chromatographic separation D) To monitor the progress of an organic synthesis reaction 14. The solubility of salicylic acid in water is 7.8g/100ml at 100°C and 0.25g/100ml at 25°. Estimate how much water is needed to recrystallize a 19g sample of salicylic acid? A) 150ml B) 250ml C) 300ml D) 400ml

PART 3- LABORATORY EQUIPMENT EQUIPMENT NAME FUNCTION To hold test tubes. Attaches to a retort stand to support glassware being heated. To pour liquid from a large container into a small container. To provide a flame during an experiment. ones To light the Bunsen burner. To attach test tubes to a retort stand. To clean substances out of a test tube. To hold a hot crucible or flask. To hold a hot test tube. To place on the lab bench to prevent burning or to use with ring clamp. To transfer small amounts of liquid. To grow bacteria or contain small experiments. To hold liquids. To measure liquids. To contain experiments (a stopper can be used to close the flask). To hold a hot beaker. To perform an experiment with a different substance in each well. To hold chemicals and perform experiments in. To scoop and transfer small amounts of substances, To stir during experiments that involve mixing or dissolving.

Atomic weights are not provided, but please use rounded-off values to the nearest whole number.(examples: 24.305, use "24"; 107.8682, use "108"; 1.00784, use "1"; 15.999, use "16") Final answer in 3 decimal places 1. A fat sample with combination free fatty acids required 8mL and 5mL of standard hydrochloric acid for blank and sample titration, respectively. The normality of the standard hydrochloric acid is 0.93N and the weight of the sample is 3 grams. Calculate the saponification value. 2. A 500mg oil sample is taken from a conical flask and is dissolved in 50mL distilled alcohol. An indicator is added and is then titrated against 0.112N KOH until a slight pink color appears. It took 17.6mL of the titrant to reach the endpoint. What is the sample’s Acid Value?

Tom, an analytical chemist, bought a bag of decaffeinated coffee from a grocery store. However,Tom suspected that he might have received regular coffee and therefore decided to analyze hiscoffee for caffeine. In the lab, he took 0.5 mL of the brewed coffee and diluted it in water tomake a 100.0 mL solution. He performed four analyses and found the concentrations to be 4.69,3.99, 4.12, and 4.50 mg/L, respectively. (Assume the density of all solutions is 1.000 g/mL,1oz= 28.35 mL).(a) Report the concentration (in mg/L) of caffeine in the brewed coffee using the format asaverage ± standard deviation. (Note this is not the concentration in the diluted solution.)(b) Look up the caffeine content of regular vs. decaffeinated coffee. Do you think that Tom wasgiven the wrong type of coffee?(c) Caffeine intake of 300 mg per day reportedly has no adverse effects in the vast majority ofthe adult population. If Tom drinks 3 cups (8 oz/cup) of this coffee daily, is his intake withinthis known safe…

How do you separate sodium hydroxide from the crude mixture?

Nitrous Acid Test Procedure: Make a solution of  4 grams NaNO3 in 16 mL water. Put 2 mL of concentrated hydrochloric acid into a 10x75-mm test tube and add 0.5 ml of amine. Cool the solution in a water-ice slush to zero degrees celcius. Add the nitrile solution slowly, dropwise, until a drop of the reaction mixture gives a blue spot on starch-iodide paper.  The following should be tested: (NOTE: Include the observations and reaction equation) A. PRIMARY ALIPHATIC AMINES (Like Butylamine of Cyclohexylamine) B. PRIMARY AROMATIC AMINES I. Aniline + nitrous acid; then heat. II. Aniline + nitrous acid; then B-Napthol.

What was the purpose of adding the n-hexanes to the crude oil?