Number of He atoms = number of moles $\times N_A$
4 g of He: $\frac{4}{4} \times 6.022 \times 10^{23} = 6.022 \times 10^{23}$ atoms
2.271098 L at STP: $\frac{2.271098}{22.4} \times 6.022 \times 10^{23} \approx 0.61 \times 10^{23}$ atoms
4 mol of He: $4 \times 6.022 \times 10^{23} = 24.088 \times 10^{23}$ atoms
4 u of He: 1 atom
So the highest number of He atoms is in 4 mol of helium.
ConceptComparing number of atoms across different mole-based quantities
Mole Concept and Avogadro Number in past papers
2 questions from this chapter have appeared across 2 exam years.
