Answer to Question #128562 in General Chemistry for Hannah Ruth

Question

Liquid bromine (Br2) has a density of 2.91g/mL. How many molecules of bromine are contained in a 8.50-mL sample of bromine?

Answer 1

m = V×ρ

m(Br₂) = 8.50 mL × 2.91 g/mL = 24.735 g

M(Br₂) = 159.808 g/mol

n = m/M

n(Br₂) = 24.735 g / 159.808 (g/mol) = 0.154 mol

One mole of Br₂ molecules contains 6.02×10²³ Br₂ molecules.

Number of molecules = n×6.02×10²³ = 0.154×6.02×10²³ = 9.27×10²² molecules.

Answer: 9.27×10²² molecules