Atablet of pain be gone aspirin, which had a mass of 1.213 g, was pulverized and 1.159 g were dissolved in 10.0 ml of ethyl alcohol and 25.0 ml of di water. the titration of this solution with 0.1052 m naoh required 15.62 ml to reach the phenolphthalein endpoint. determine the moles of naoh that reacted with the acetylsalicylic acid.

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ

Generally, observed behavior that can be formulated into a statement, sometimes mathematical in nature, is called a(n): a. observation. b. measurement. c. theory. d. natural law. e. experiment.