SAQ : What is the number of molecules in each of 32 g O2 and 44 CO2?

Question

What is the number of molecules in each of 32 g O₂ and 44 CO₂? [Ans. 6.022 × 10²³]

Answer

Given Mass of O₂ = 32 g

Gram Molecular (Molar) mass = 16 × 2 = 32 g

Number of Moles = 32\over 32 = 1

Number of molecules = Number of moles × Avogadro’s Number

= 1 × 6.022 × 10²³

∴ Number of molecules in 32 g of O₂ = 6.022 × 10²³ [Ans]

Given Mass of CO₂ = 44 g

Gram Molecular Mass of CO₂ = 12 + 16 × 2 = 44 g

Number of Moles = 44\over 44 = 1

Number of molecules = Number of moles × Avogadro’s Number

= 1 × 6.022 × 10²³

∴ Number of molecules in 44 g of CO₂ = 6.022 × 10²³ [Ans]