how many molecules are present in 8g of oxygen gas??
Molar mass of oxygen is 16 g
Molecular mass of O2 = (16 +16) g per mole.
⇒ Molecular mass of O2 = 32 g per mole.
Which means mass 1 mole of di oxygen is equal to 32 g
As 1 mole contains 6.022 × 1023 particles.
Therefore, 32 g contains → 6.022 × 1023 molecules of di oxygen.
1 g contains → 6.022 × 1023 / 32 molecules of di oxygen.
⇒ 1 g contains → 0.188 × 1023 molecules of di oxygen.
∴ 8 g contains → 0.188 × 8 × 1023 molecules of di oxygen.
Hence 8 g of oxygen gas contain 1.505 × 1023 molecules