RRB Group-D Model Paper 12 with answers for online practice

The Mole is the unit of the amount of substance.

• The amount of substance in a given sample of matter is defined as the number of distinct atomic-scale particles in it divided by the Avogadro constant ${\mathit{N}}_{\mathit{A}}$.
• The amount of substance is literally the sum of particles that make up the product.
• The Particles may be molecules, atoms, particles and electrons depending on the context.
• The value of Avogadro constant NA was defined as 6.02214076× ${10}^{23}{\mathrm{mol}}^{-1}$.
• From a purely atomistic point of view, 1 mol = 6.02214076 × ${10}^{23}$ particles and thus the conversion constant is simply ${\mathit{N}}_{\mathit{A}}$ = 1.
• The amount of substance is often referred to as the chemical amount.