Final answer:
There are 1.506 × 1025 atoms in 25.0 moles of calcium (Ca), calculated by multiplying the number of moles by Avogadro's number, which is 6.022 × 1023 atoms per mole.
Step-by-step explanation:
To calculate how many atoms are in 25.0 moles of calcium (Ca), we use Avogadro's number, which is 6.022 × 1023 atoms per mole. Multiplying the number of moles by Avogadro's number gives us the total number of atoms:
25.0 moles × 6.022 × 1023 atoms/mole = 1.506 × 1025 atoms of calcium.