Question

Calculate the mass of 1 atom of silver and 1 molecule of carbon dioxide.

Answer 1

The atomic mass of silver is 108 u and molar mass of silver is 108 g/mol. This means there are 6.023 X 10²³ atoms of silver in 108 g of silver. Thus

6.023 X 10²³ atoms of silver = 108 g

1 atom of silver = 108 / (6.023 X 10²³) g

= 1.7931 X 10^-22 g

Thus the mass of an atom of silver is 1.7931 X 10^-22 g.

The atomic mass of carbon is 12 u while that of oxygen is 16 u. The chemical formula of carbon dioxide is CO₂, so the molecular mass of carbon dioxide is 12 + 2 X (16) = 44 u. The molar mass of carbon dioxide is 44g. This means there are 6.023 X 10²³ molecules of CO₂ in 44 g of CO₂. Thus

6.023 X 10²³ molecules of CO₂ = 44 g of CO₂

1 molecule of CO₂ = 44 / ( 6.023 X 10²³ ) g

= 7.305 X 10^-22 g

So the mass of a molecule of CO₂ = 7.305 X 10^-22 g