1. Convert nanograms to grams:
* 1 nanogram (ng) = 1 x 10⁻⁹ grams (g)
2. Calculate the number of moles of uranium:
* Molar mass of uranium (U) = 238.03 g/mol
* Moles = mass (g) / molar mass (g/mol)
* Moles of uranium = (1 x 10⁻⁹ g) / (238.03 g/mol) ≈ 4.20 x 10⁻¹² mol
3. Calculate the number of atoms:
* Avogadro's number = 6.022 x 10²³ atoms/mol
* Number of atoms = moles x Avogadro's number
* Number of uranium atoms = (4.20 x 10⁻¹² mol) x (6.022 x 10²³ atoms/mol) ≈ 2.53 x 10¹² atoms
Therefore, there are approximately 2.53 x 10¹² atoms of uranium present in 1 nanogram of uranium.
