A 1.000 mL aliquot of a solution containing Cu2 and Ni2 is treated with 25.00 mL of a 0.03443 M EDTA solution. The solution is then back titrated with 0.02270 M Zn2 solution at a pH of 5. A volume of 20.01 mL of the Zn2 solution was needed to reach the xylenol orange end point. A 2.000 mL aliquot of the Cu2 and Ni2 solution is fed through an ion-exchange column that retains Ni2 . The Cu2 that passed through the column is treated with 25.00 mL of 0.03443 M EDTA . This solution required 16.17 mL of 0.02270 M Zn2 for back titration. The Ni2 extracted from the column was treated witn 25.00 mL of 0.03443 M EDTA . How many milliliters of 0.02386 M Zn2+ is required for the back titration of the Ni2+ solution?

Which part of a feedback mechanism is able to monitor the conditions outside of cells and usually uses nerve cells to relay this information to an intergrating center

Astudent is given a sample of a blue copper sulfate hydrate. he weighs the sample in a dry covered porcelain crucible and got a mass of 23.875 g for the crucible, lid, and sample. the mass of the empty crucible and lid was found earlier to be 22.652 g. he then heats the crucible to expel the water of hydration, keeping the crucible at red heat for 10 minutes with the lid slightly ajar. on colling, he finds the mass of crucible, lid, and contents to be 23.403 g. the sample was changed in the process to very light clue anhydrous cuso4. if there are again 100.0 g of hydrate, how many grams of cuso4 are in it? how many moles of cuso4? (hint: molar mass of cuso4 = 159.6 g / mole. what per cent of the hydrate is cuso4? you may convert the mass of cuso4 to moles.)

Ageologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit. based on this information, the sample mineral has to be softer than a. orthoclase. b. fluorite. c. apatite. d. corundum.