A 3.50-gram sample of Streptomycin powder was tested for its water content. If the water equivalence factor of the KF reagent was 4.6, what is the percentage water content of the sample if 9.2 ml of the KF reagent was used?

#7 Name: Date: Section: Prelaboratory Assignment: Determination of the Hardness of Water A 0.512 g sample of CaCO3 is dissolved in 12 M HCl and the mixture is diluted to 250 mL. a) How many moles of CaCO3 are used? moles b) What is the [Ca²+] in the 250 mL solution? b) How many moles of Ca²+ are in a 25 mL sample of the 250 mL solution? moles 4. mall amount of MgCl₂ solution is added to a 25 mL aliquot of the solution in problem with EDTA to the Eriachrome Black T end point. The mixed nd point. A similar amount of

Which of these acts as a buffer in embalming fluids?     sodium lauryl sulfate     EDTA     lanolin     calcium

A 1.43 x 10-4 L solution of 45.7 mg/mL protein was analyzed using the Kjeldahl procedure. After digestion of the protein, the liberated NH3 was collected in 9.80 mL of  0235 M HCl.  The unreacted acid required 10.75 mL of a standard solution of 0.0149 M NaOH for complete titration.  Calculate the weight percent of nitrogen in the protein.  (Molar mass N = 14.00674 g/mol)

Please help to calculate a dilution factor and the amount of mg in the vitamin. There are 1.13 ppm of iron. An unknown vitamin was dissolved in 25 ml of 6 M of HCl. Then brought up to 100 mL with DI water.  Dilute 5.00 mL of solution A to 100.0 mL in a 100.0-mL volumetric flask. This is Solution B.Transfer 10.00 mL of Solution B to a 100.0-mL volumetric flask.  Based on this dilution, the dilution factor is 200, so how many mg of iron is in vitamin?

How many grams of Ba(103)2 (487 g/mol) can be dissolved in 400 mL of water at 25°C. (Ksp of Ba(1O3)2 = 1.57 x 10-9) Ba(103)2 Ba2+ + 2103 O 0.298 g 0.122 g 0.221 g O 0.926 g O 0.143 g

Post-lab question #1: Ag2CrO4 (s) + 2 Ag* (aq) + CrO42- (aq) If the Ksp for Ag2CrO4 is 1.1 x 10-10, How many milligrams of Ag2CrO4 will dissolve in 10.0 mL of water? None of the above 100 mg 1.0 mg 10. mg

To determine the pKa of PNP, a student needs to prepare a solution of 18.0 µM PNP in 26.0 mM MES pH 6.3, with a total volume of 950 µL.  Stock solutions of 0.350 mM PNP and 100.0 mM MES pH 6.3 are available.  Calculate the volume of PNP required to make the solution (in µL).

Molar concentration of the bleach stock solution: .134 mol/L Solutions(Dilutions) Concentration% Experiment 1 0.25 Experiment 2 0.50 Experiment 3 1.0 Fill in the OCl- molar concentrations for each experiment. Solutions(Dilutions) OCl- Concentrationmol/L Experiment 1   Experiment 2   Experiment 3

A protocol calls for 1 liter of solution that is 1.5 % (w/v) NaCl, 5mM Tris (pH 8.0), 10% (w/v) Carnation Instant Milk (we really do use this in lab!), and 0.03% (v/v) Tween-20 detergent. How do you make this solution?