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A chemist must prepare 550.0 mL of potassium hydroxide solution with a pH of 13.60 at 25 C. She will do this in three steps: Fill a 550.0 mL volumetric flask about halfway with distilled water. E Weigh out a small amount of solid potassium hydroxide and add it to the flask. Fill the flask to the mark with distilled water. ol Calculate the mass of potassium hydroxide that the chemist must weigh out in the second step. Round your answer to 2 2 significant digits. A lg xio 3 ?. A chemist must prepare 250.0 mL of nitric acid solution with a pH of 0.70 at 25 C. He will do this in three steps: Fill a 250.0 mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (6.0M) stock nitric acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated nitric acid that the chemist must measure out in the second step. Round your answ to 2 significant digits. | ml x10 5