Given : Density of Bromine = 3.12 g/mL
Formula : Density = Mass / Volume
Part A :
Given Volume = 125 mL
Density = Mass / Volume
So, Mass = Density x Volume
= 3.12 x 125
= 390 grams
Part B :
Given mass = 85.0 gm
Density = Mass / Volume
So, Volume = Mass / Density
= 85 / 3.12
= 27.24 mL