How many moles of br2(l) (mm = 159.80 g/mol) are in 13.9 ml of liquid bromine? the density of br2(l) is 3.12 g/ml?

             Moles  =  0.271 mol

Solution:

Step 1: Calculate Mass of Br₂ as;

                               Density  =  Mass  ÷  Volume

Solving for Mass,

                               Mass  =  Density  ×  Volume

Putting values,

                               Mass  =  3.12 g.mL⁻¹  ×  13.9 mL

                               Mass  =  43.36 g

Step 2: Calculate Moles of Br₂ as;

                               Moles  =  Mass  ÷  M.Mass

Putting values,

                               Moles  =  43.36 g ÷  159.80 g.mol⁻¹

                              Moles  =  0.271 mol

it is stable as it is in group 0 which have full outer shells of electrons