A chemist must prepare 700.0 mL of potassium hydroxide solution with a pH of 12.00 at 25 °C. She will do this in three steps: • Fill a 700.0 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. ☐ x10

Consider the following data on some weak acids and weak bases: name acetic acid hydrofluoric acid acid solution 0.1 M KCH3CO₂ 0.1 M CH3NH3Br 0.1 M NaI 0.1 M NaF Ka formula HCH3CO₂ 1.8 x 10 HF 6.8 × 10 Use this data to rank the following solutions in order of increasing pH. In other words, select a '1' next to the solution that will have the lowest pH, a '2' next to the solution that will have the next lowest pH, and so on. X -4 pH choose one choose one choose one choose one base Ś Kb formula methylamine CH3NH₂ 4.4 x 107 CHN 1.7×10 9 name pyridine

A chemist must prepare 450.0 mL of nitric acid solution with a pH of 1.60 at 25 °C. He will do this in three steps: • Fill a 450.0 mL volumetric flask about halfway with distilled water. • Measure out a small volume of concentrated (5.0M) 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 answer to 2 significant digits. ||mL x10 ?

A chemist dissolves 815. mg of pure barium hydroxide in enough water to make up 110. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Be sure your answer has the correct number of significant digits. 0 x10 ×

A chemist must prepare 800.0 mL of potassium hydroxide solution with a pH of 12.90 at 25 °C. She will do this in three steps: • Fill a 800.0 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.

Calculate the pH values of the following solutions. All solutions are prepared in water at 25 oC unless noted otherwise. Kw = 1.0 × 10−14 = [H3O+]×[OH−] at 25 oC. The neutral pH of pure water is 7.00 at 25 °C. If the Kw is 1.47×10−14 at 40 °C, calculate the neutral pH of pure water at 40 °C. A neutral pH means the pH of a solution when [H3O+] = [OH−]

A chemist dissolves 204. mg of pure barium hydroxide in enough water to make up 170. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Round your answer to 3 significant decimal places. 0 x10 X Ś

A chemist dissolves 215. mg of pure sodium hydroxide in enough water to make up 190. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Round your answer to 3 significant decimal places. ☐ x10 G

A chemist must prepare 600.0mL of nitric acid solution with a pH of 0.90 at 25°C. He will do this in three steps: Fill a 600.0mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (9.0M) 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 answer to 2 significant digits.

A chemist must prepare 400.0 mL of hydrochloric acid solution with a pH of 1.20 at 25 °C. He will do this in three steps: • Fill a 400.0 mL volumetric flask about halfway with distilled water. • Measure out a small volume of concentrated (8.0M) stock hydrochloric acid solution and add it to the flask. • Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrochloric acid that the chemist must measure out in the second step. Round your answer to 2 significant digits. |mL x10