What is meant by atomicity of a molecule?

LokeshCBSE · April 4, 2019, 11:09am

- What is meant by atomicity of a molecule? Give one example of triatomic molecule.
- Sodium carbonate (Na₂CO₃ . 10H₂O) is an important industrial chemical. Calculate its atomic mass. [Atomic mass of Na = 23 u, C = 12 u, O = 16u and H = 1 u]
What is the number of zinc (Zn) atoms in a piece of zinc weighing 10 g?

LokeshCBSE · April 4, 2019, 11:20am

- Atomicity of a molecule is defined as the number of atoms present in a molecule. e.g. Ozone (O₃) is a triatomic molecule.
- Atomic mass of sodium carbonate (Na₂CO₃ . 10H₂O) = 2Na + 1C + 3O + 10(2H + 10)
  = 2 x 23 + 12 + 3 x 16 + 10 (2 x 1 + 16)
  = 46 + 12 + 48 + 180 = 286 u
Number of moles of zinc (Zn)
1 mole of zinc contains 6022 x 10²³ atoms