Answer to Question #169408 in Chemistry for Jamie Mayhugh

Question

Potassium bromide reacts with chlorine to produce potassium chloride and bromine. How Many grams of bromine are produced when 15.0 g of potassium bromide are used?

Answer 1

Solution:

The balanced chemical equation:

2KBr + Cl₂ → 2KCl + Br₂

According to the equation above: n(Br₂) = n(KBr)/2

Moles of KBr = Mass of KBr / Molar mass of KBr

The molar mass of KBr is 119.002 g mol^-1.

Hence,

n(KBr) = (15.0 g) / (119.002 g mol^-1) = 0.126 mol

n(Br₂) = n(KBr)/2 = 0.126 mol / 2 = 0.063 mol

Moles of Br₂ = Mass of Br₂ / Molar mass of Br₂

Mass of Br₂ = Moles of Br₂ × Molar mass of Br₂

The molar mass of Br₂ is 159.808 g mol^-1.

Hence,

Mass of Br₂ = (0.063 mol) × (159.808 g mol^-1) = 10.0679 g = 10.07 g

Mass of Br₂ = 10.07 g

OR (according to the equation):

(15.0 g KBr)×(1 mol KBr/119.002 g KBr)×(1 mol Br₂/2 mol KBr)×(159.808 g Br₂/1 mol Br₂) = 10.07 g Br₂

Answer: 10.07 grams of bromine (Br₂) are produced.