The mass of C-12 and C-14 isotopes are found as 98% and 2% respectively. The number of atoms of C-14 in 12 g of sample are

To determine the number of carbon-14 (C-14) atoms in a 12 g carbon sample with isotopic abundances of 98% carbon-12 (C-12) and 2% C-14, follow these steps:

1. Calculate the mass of C-14 in the sample:
   • Since C-14 constitutes 2% of the total carbon mass:
     • Mass of C-14 = 2% of 12 g = 0.02 × 12 g = 0.24 g
2. Determine the number of moles of C-14:
   • The molar mass of C-14 is approximately 14 g/mol.
   • Number of moles of C-14 = Mass of C-14 / Molar mass of C-14
     • = 0.24 g / 14 g/mol
     • ≈ 0.01714 mol
3. Calculate the number of C-14 atoms:
   • Using Avogadro's number (6.022 × 10²³ atoms/mol):
     • Number of C-14 atoms = Number of moles × Avogadro's number
     • = 0.01714 mol × 6.022 × 10²³ atoms/mol
     • ≈ 1.032 × 10²² atoms

Therefore, the number of C-14 atoms in the 12 g carbon sample is approximately 1.032 × 10²² atoms.