A chemist must prepare 650.0 mL of potassium hydroxide solution with a pH of 13.70 at 25 °C. He will do this in three steps: Fill a 650.0 mL volumetric flask about halfway with distilled water. Weigh out a small amount of solid potassium hydroxide and add it to the flask Fill the flask to the mark with distilled water Calculate the mass of potassium hydroxide that the chemist must weigh out in the second step. Round your answer to 2 significant digits.