the importance of the nature of light in the gaining of understanding of the quantum mechanical model of the atom

How do scientists think that gravity affected the formation of our solar system?

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?

What are the coefficients to balance the following equation? ba+br2=babr2