Question

Which of the following formulae is/are correct to calculate the number of moles?

• A. Number of moles = $\text{Number of particles}\times \text{Avogadro number}$
• B. Number of moles of gas at STP = $\frac{\text{Volume in STP (litre)}}{\text{22.4 L}}$
• C. Number of moles of molecules = $\frac{\text{Mass in gram}}{\text{Gram molecular mass}}$
• D. Number of moles of atoms = $\frac{\text{Mass in gram}}{\text{Gram atomic mass}}$

Answer 1

Answer: (B), (C), (D)

Number of moles of atoms = $\frac{\text{Mass in gram}}{\text{Gram atomic mass}}$

The correct formulae are:

• Number of moles of atoms = $\frac{\text{Mass in gram}}{\text{Gram atomic mass}}$
• Number of moles of molecules = $\frac{\text{Mass in gram}}{\text{Gram molecular mass}}$
• Number of moles = $\frac{\text{Number of particles}}{\text{Avogadro number}}$
• Number of moles of gas at STP = $\frac{\text{Volume in STP (litre)}}{\text{22.4 L}}$