Question

The number of atoms in 52 g of He is

• A. 78.299 × 10²⁴ atoms
• B. 7.820 × 10^-24 atoms
• C. 7.829 × 10²⁴ atoms
• D. 78.234 × 10²⁵ atoms

Answer 1

Answer: (C)

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