One series of emission lines for the hydrogen atom, called the Pfund series, occurs in the infrared region. It results when an electron changes from higher energy levels to a level with n = 5. Calculate the wavelength and frequency of the lowest energy line of this series. n=1 is ground The lowest energy line in this series occurs for an electron falling from n = 6 to n = 5. State %3D AE = -2.662x10-20 J 2 = 7.462x106 m v = 4.018x1013 1/s (Hz)

A pool contains 4500 gallons of 1.4% chlorine solution, which means that 1 4% of the liquid in the pool is actially chlorine: the rest is water. The goal is to find how many gallons of chlorine would need to be added to increase the concentration in the pool to 3%. Round your answer to the nearest gallon. ___ gallons would need to be added to increase the concentration in the pool to 3%

Note: The explanation of this work would be we did a work on the process of preparing diverse solution sets and regarding that these are the following sets of questions.  PART: 2 What happens to the solution's concentration when you add more solute to the same volume of solvent? How to raise the concentration of an aqueous solution? When is the ppm concentration applied? What do you conclude from this lab? Was your hypothesis confirmed or not? Explain your answer.

Please help I'm not sure how to solve these.  A solution is prepared by dissolving 20g of NaCl (f.w.= 58.44 g mol^-1), a nonvolatile solute, in enough water (m.w. = 18.02 g mol^-1) to result in exactly 1 L of solution at 25 C. The density of the solution is 1 g mL ^-1.   How do you calculate freezing point of the solution as well as vapor pressure and the osmotic pressure? I understand boiling point.