Consider the laboratory on hplc analysis of components in diet soft drinks. your standard solutions for caffeine were prepared from a stock solution of 0.40 mg/ml caffeine, from which you drew, 1.0, 2.0, 3.0, 4.0 and 5.0 ml and diluted each one to 50.0 ml. calculate the concentration of the most concentrated standard solution. for the same lab as in problem 1, suppose you plotted peak height (y-axis) vs. concentration in mg/ml (x-axis), and the slope was found to be 25.0 ml/mg. if the peak height for the unknown was 15.5, calculate the concentration in the unknown. assume the intercept was zero.

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.)

Identify the electromagnets with poles that are reversed from the electromagnet shown above

What is the molar mass of potassium nitrate, kno3