2.77 × 10²³ Br Atoms
Mass of CH₂Br₂ = 39.9 g
M.Mass of CH₂Br₂ = 173.83 g.mol⁻¹
Step 1: Calculate Moles of CH₂Br₂ as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 39.9 g ÷ 173.83 g.mol⁻¹
Moles = 0.23 mol
Step 2: Calculate number of CH₂Br₂ Molecules,
As 1 mole of any substance contains 6.022 × 10²³ particles (Avogadro's Number) then the relation for Moles and Number of CH₂Br₂ Molecules can be written as,
Moles = Number of CH₂Br₂ Molecules ÷ 6.022 × 10²³ Molecules.mol⁻¹
Solving for Number of CH₂Br₂ Molecules,
Number of CH₂Br₂ Molecules = Moles × 6.022 × 10²³ Molecules.mol⁻¹
Putting value of moles,
Number of CH₂Br₂ Molecules = 0.23 mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of CH₂Br₂ Molecules = 1.38 × 10²³ CH₂Br₂ Molecules
Step 3: Calculate Number of Br Atoms:
As,
1 Molecule of CH₂Br₂ contains = 2 Atoms of Br
So,
1.38 × 10²³ Molecules of CH₂Br₂ will contain = X Atoms of Br
Solving for X,
X = (1.38 × 10²³ CH₂Br₂ × 2 Br) ÷ 1 CH₂Br₂
X = 2.77 × 10²³ Br Atoms
