Consider four distinct physical properties: boiling point, melting point, solubility, and density. Which of these physical properties do you think allows thin layer chromatography (TLC) to work? Choose one then, explain your reasoning

You dissolve 14 g of Mg(NO,2 in water and dilute to 750 mL. What is the molarity of this solution? Show your work.

1. A wastewater sample has the following composition: NO3 = 37 mg/L as N CO3²-2.5 x 10 mol/L PO4³ = 10 meq/L Ca²+ = 75 mg/L as CaCO3(s) Express each of the above concentrations in mg/L, mol/L, meq (of charge)/L, and ppm. Make and list any necessary assumptions. Show your work and summarize the results in a table.

Calculate the concentration (Mdil) of potassium permanganate (KMnO4) when 600 mL (Vconc) of the potassium permanganate solution is added to 400 mL of water. Note: first add the potassium permanganate solution (choose dropper) in the absence of water, move the sensor over the solution, and determine the concentration of the solution prior to adding water (Mconc). Knowing these three pieces of data, you can now calculate (Mail), and enter this calculated number as your answer. You can also confirm your answer by adding 400 mL of water to your 600 mL of potassium permanganate solution and checking the concentration with the sensor (NOTE: the sensor concentration will likely be slightly off the calculated number since it's difficult to add exact volumes in the simulator). Please report your numerical answer only with three significant figures and NO units (eg., 1.23). Mdildil MconcVconc A R

Help with the following question. Ksp for Co(OH)2 is 5.02 x 10^-6

Which is correct?     Random errors affect accuracy and systematic errors affect precision.     An accurate result shows agreement with the true or accepted value.     Precise results can contain significant random error, but little systematic error.     The standard deviation is a good measure of accuracy.   Polydimethylsiloxane (PDMS) stationary phases have low polarities.  Which of the following statements is TRUE about gas chromatography using PDMS stationary phases?     The gas chromatography column is typically packed with silica microparticles.     An oven is used to control the column temperature because a constant temperature is always needed in gas chromatography     Octane (C8H18, boiling point: 126 ºC) is eluted later than dodecane (C12H26, boiling point: 216 ºC)     3-Pentanone ((C2H5)2CO, boiling point: 102 ºC) is eluted later than propanol (CH3CH2CH2OH, boiling point: 97 ºC)

A student obtains 0.95 g of crude 9-fluorenone and performs a recrystallization in cyclohexane (13 mL per 1 g crude 9-fluorenone). If the student recovered 0.57 of pure 9-fluorenone, what was the percent recovery of the recrystallization? Report your answer to no decimal places. Your Answer: Answer

We used tab water to extract caffeine from tea instead of using distilled water. How does it affect your result? Explain it scientifically. If you forgot to add anhydrous sodium sulfate, how does it affect your result? Explain it scientifically If you forgot to cap the TLC chamber, how does it affect your result? Explain it scientifically.

Effect of Particle Size on the Rate of Dissolving Time required for all NaCl to dissolve Sample Results after 2 minutes shaking Do you think the size of the crystal makes a difference in how fast the salt dissolves? Explain why the differences you observed and why they happened. Effect of Temperature on the Rate of Dissolving Time required for all NaCl to dissolve Sample Observations Do you think the temperature of the water makes a difference in the rate at which the NaCl dissolves? Explain why the differences you observed and why they happened. Page 3 of 6

You have a micro tube containing 1mL of a solution with 4.3x10^4 cells/mL and you are to produce a solution that contains 43 cells/mL. The most accurate way to do this is to preform a series of 1:10 dilutions (add 1mL of stock solution to 9mL of water to achieve a factor of 10 dilution). How many of these dilutions must you preform to achieve the desired solution?