Final answer:
To determine the number of atoms in 30.0 g of As (arsenic), we can use Avogadro's number and the molar mass of arsenic. By dividing the mass by the molar mass, we find the number of moles, which can then be multiplied by Avogadro's number to find the number of atoms.
Step-by-step explanation:
In order to determine the number of atoms in 30.0 g of As (arsenic), we can use Avogadro's number and the molar mass of arsenic. Avogadro's number is defined as 6.02 × 10^23 atoms per mole. The molar mass of arsenic is 74.92 g/mol.
To calculate the number of moles of arsenic in 30.0 g, we divide the mass by the molar mass: 30.0 g / 74.92 g/mol = 0.400 mol.
Finally, we can multiply the number of moles by Avogadro's number to find the number of atoms: 0.400 mol * 6.02 × 10^23 atoms/mol = 2.408 × 10^23 atoms.