Q54 / 180 · AIIMS 2014 · Chemistry

The number of atoms in $52 \mathrm{~g}$ of $\mathrm{He}$ is

  • A
    $78.299 \times 10^{24}$ atoms
  • B
    $7.820 \times 10^{-24}$ atoms
  • Correct answer
    C
    $7.829 \times 10^{24}$ atoms
  • D
    $78.234 \times 10^{25}$ atoms

Solution

Number of atoms $=\frac{N_A \times \text { mass }}{\text { At. mass }}$ $=\frac{6.023 \times 10^{23} \times 52}{4}=7.829 \times 10^{24}$ atoms

Hence, the correct answer is option: 'C'.

More Some Basic Concepts of Chemistry Questions