Which of the following contains the greatest number of atoms?

A - 1g of butane

B - 1g of Nitrogen

C - 1g of silver

D - 1g of water

Answer

A - 1g of butane

Explanation: 

Molecular mass of Butane (C ₄ H ₁₀ ) is 58g/mol

There are 14 atoms in the molecule

So, 1g of butane means 1/58 moles = 0.0172 moles

Total number of atoms = 14 x 0.0172 x 6.022 x 10 ²³ = 1.45 x 10 ²³ atoms

Molecular mass of Nitrogen (N ₂ ) is 28g/mol

There are 2 atoms in the molecule

So, 1g of nitrogen means 1/28 moles = 0.0357 moles

Total number of atoms = 2 x 0.0357 x 6.022 x 10 ²³ = 0.43 x 10 ²³ atoms

Molecular mass of Silver (Ag) is 108g/mol

There are is 1 atom in the molecule

So, 1g of silver means 1/108 moles = 0.0092 moles

Total number of atoms = 0.0092 x 6.022 x 10 ²³ = 0.054 x 10 ²³ atoms

Molecular mass of Water (H ₂ O) is 18g/mol

There are 3 atoms in the molecule

So, 1g of water means 1/18 moles = 0.055 moles

Total number of atoms = 3 x 0.055 x 6.022 x 10 ²³ = 1.003 x 10 ²³ atoms

Thus 1g of butane has greatest number of atoms