Answer:
4.03 × 10²² particles of beryllium sulfide.
Step-by-step explanation:
The formula to find the number of particles is:
Number of particles/atoms = number of moles × (6.02 × 10²³)
6.02 × 10²³ = Avogadro's number
But first, we will have to find the number of moles. This can be found using the formula:
Number of moles = mass ÷ Mr
Mr of BeS = 9 + 32.1 = 41.1
Number of moles = 2.74 ÷ 41.1 = 0.067 mol
Now that we know the number of moles, we can find the number of particles.
Number of particles = 0.067 × 6.02 × 10²³
∴ Number of particles = 4.03 × 10²²