How many grams of chlorophyll are needed to generate an osmotic pressure of 1.55 atm when dissolved in 216ml of an ethanol solution at 298k

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?

Element before carbon on the periodic table

If an atom has 12 protons and 13 neutrons