Answer: number of atoms is 5.21 · 10^24
Explanation: Atomic mass of Be is 9.012 g/mol.
Number of moles n = m/M = 78.0 g / 9.012 g/mol =
Multiply this with Avogadro number Na = 6.022*10^23 1/mol
25m³.
500mL = 500cm³
25m³ = 2,500cm³
5.5x9 = 49.5(cm³)
25m³ is the smallest among the others.
