Question

Which contains the greatest number of moles of oxygen atoms? 

1. 1 mol of ethanol 

2. 1 mol of formic acid 

3. 1 mol of H₂O

Answer 1

1. 1 mol of ethanol 

C₂H₅OH (ethanol) – Molar mass

 = 24 + 6 + 16 

= 46 

46 g of ethanol contains 1 × 6.023 × 10²³ number of oxygen atoms.

2. 1 mol of formic acid. 

HCOOH (formic acid) – Molar mass 

= 2+12 + 32 

= 46 

46 g of HCOOH contains 2 × 6.023 × 10²³ number of oxygen atoms.

3. 1 mol of H₂ O 

H₂O (water) – Molar mass 

= 2 + 16 

= 18 

18 g of water contains 1 × 6.023 × 10²³ number of oxygen atoms. 

∴ 1 mole of formic acid contains the greatest number of oxygen atoms.