Which refers to the number of wavelengths that pass a fixed point in a second? HURRY

An aqueous solution of potassium hydroxide is standardized by titration with a 0.194 m solution of hydrobromic acid. if 25.2 ml of base are required to neutralize 24.2 ml of the acid, what is the molarity of the potassium hydroxide solution? m potassium hydroxide

If 1.63 times 10 negative 4 of helium dissolves in 100.0g of water, what is the concentration in parts per million

If a plot weight (in g) vs. volume (in ml) for a metal gave the equation y= 13.41x and r^2=0.9981 what is the density of the metal?