Final answer:
To find the number of atoms in 8.38 g of krypton, divide the mass by the molar mass to get the moles, then multiply by Avogadro's number, yielding approximately one-tenth Avogadro's number of atoms.
Step-by-step explanation:
To calculate how many atoms are contained in a sample of krypton (Kr) that weighs 8.38 g, we use Avogadro's number and the molar mass of krypton. Krypton's atomic mass is approximately 83.8 amu, making its molar mass 83.8 g/mol. The number of moles of krypton in the sample is found by dividing the sample's mass by the molar mass: (8.38 g) / (83.8 g/mol) = 0.1 mol approximately. Each mole contains Avogadro's number of atoms, so the number of atoms in the sample is 0.1 mol multiplied by Avogadro's number (6.02×10²³ atoms/mol).