Question

How many atoms are in 3.50 moles of calcium (Ca)?

Answer 1

there are always 6.02214 x 10^23 (Avogadros number) atoms in a mole. so times this by 3.5

Answer 2

1 mole of Ca has an Avogadro Number of atoms in it. = 6.02 × 10²³

3.5 moles would then have:    3.5 × (6.02 × 10²³)

                                            =   3.5 × 6.02 × 10²³ = 21.07× 10²³

                                            =  2.107×10²⁴ atoms.