An amino acid mixture of phenylalanine, glycine and glutamic acid is to be separated by paper chromatography. The solvent is less polar than water. Which of these amino acids will have the highest Rf value and which the lowest? Explain.

You are preparing 1 Lt of TAE (Tris Acetate EDTA) gel running buffer from a 50x stock solution. How much 50 x TAE and how much water will you combine?

Lipids from an organic sample are extracted separately by column chromatography using the ff eluants: 1st eluant - chloroform: methanol: water (6:3:1) 2nd eluant - methanol: chloroform (9:1) 3rd eluant – petroleum ether: ethyl ether (1:1) Test results for each eluate are tabulated below. Identify the possible lipid present in each eluate. Test Reagents 1. KHSO4 2. HNO3,(NH4)3MoO4 3. CHCl3, acetic anhydride, conc. H2SO4 4. -naphthol, conc. H2SO4 5. Hydroxylamine HCl, FeCl3 6. ninhydrin reagent POSSIBLE LIPIDS: Triacylglycerol, cholesterol, sphingomyelin, lecithin

If I am making 500ml of a solution with 0.625ml ITS, 0.0035ml Linoleic acid, 20ml Nu-serum, 0.75g BSA, and DMEM:F12 as my solvent, how best would I make this solution and what tools would be the most accurate to use?

How would I calculate the amount of each component in each solution?  Stock solutions provided: 0.5 M EDTA, pH 8 10% bromophenol blue 10% xylene cyanol Sucrose powder Tris powder Glacial acetic acid  Solution A: 50 mL of 50x Tris Acetate EDTA (TAE) Buffer 2M Tris Base 50mM EDTA, pH 8 11.4% (v/v) glacial acetic acid Solution B: 1L of 1x TAE Buffer 40mM Tris-acetate 1mM EDTA Solution C: 5mL of 10x Loading Dye 0.25% (w/v) bromophenol blue 0.25% (w/v) xylene cyanol 66.5% (w/v) sucrose 100mM EDTA, pH 8

If a 250 ml solution of ethanol in water is prepared with 4 ml of absolute ethanol (100%), what is the dilution factor?

The ionization of p-nitrophenol is shown below (pKa = 7.0): a. Identify the weak acid and conjugate base. b. At pH 7, what are the relative concentrations of ionized and un-ionized p-nitrophenol? c. If enough concentrated hydrochloric acid is added to a solution of p-nitrophenol to lower the pH from 7 to 5, what will happen to the relative concentrations of the ionized and un-ionized forms? d. Ionized p-nitrophenol has a yellow color, while the un-ionized form is colorless.  The yellow color can be measured using a spectrophotometer at 400nm.  In order to determine the total amount of p-nitrophenol in a solution, would you perform the spectrophotometer reading at an acidic or basic pH?  Clearly explain why? e. A solution of p-nitrophenol at pH 7.95 was found to have an A400 of 0.255 .  What is the total concentration (in µM) of p-nitrophenol (ionized plus un-ionized) in the solution?  The molar extinction coefficient of p-nitrophenol is 18,500 M-1cm-1 and the pKa is 7.

A buffer solution is composed of 1.00 mol of acid and 1.75 mol of the conjugate base. If the pKa of the acid is 3.60, what is the pH of the buffer? pH=

If skin cleaning solution is to be diluted 1 teaspoon to 64 ounces of water, how much water would need to be added to a container containing 1/4 teaspoon of skin cleaning solution?

If equal portions of tretinoin gel, 0.1% w/w and 0.04% w/w are combined, what would be the resultant percentage strength?