You are asked to prepare 500. mL 0.200 M acetate buffer at pH 4.90 using only pure acetic acid ( MW=60.05 g/mol, pKa=4.76), 3.00 M NaOH, and water. How many grams of acetic acid will be needed to prepare the 500. mL buffer? Note that the given concentration of acetate refers to the concentration of all acetate species in solution.

Explain what happens at the saturation point when adding salt to water at room temperature.

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?

Before it was launched, a helium-filled balloon had a pressure of 201 kpa at a temperature of 27°c. at an altitude of 15,000 m, the pressure had decreased to 2.5 kpa and the temperature had dropped to -14 °c. the volume of the balloon increased to 59.3 m3. what is the original volume of the balloon? 13 m3 0.85 m3 0.077 m3 1.17 m3