Which of the following gas samples contains the same number of molecules as 3.4 g of ammonia ( NH ₃ )?

Step-by-step solution

Molar mass of NH ₃ = 14 + 3 = 17 g/mol Number of moles of NH ₃ = 3.4 17 = 0.2 mol Number of molecules is directly proportional to the number of moles. We check the number of moles for each option: For H ₂ S , molar mass = 34 g/mol . Moles = 3.4 34 = 0.1 mol For O ₂ , molar mass = 32 g/mol . Moles = 8.0 32 = 0.25 mol For SO ₂ , molar mass = 64 g/mol . Moles = 12.8 64 = 0.2 mol For CO ₂ , molar mass = 44 g/mol . Moles = 4.4 44 = 0.1 mol Since 12.8 g of SO ₂ has 0.2 mol , it contains the same number of molecules as 3.