Answer:
2.047 × 10^22 atoms.
Step-by-step explanation:
To calculate the number of atoms (nA) in AlCl3, we first need to find the number of moles in the compound, AlCl3.
Molar mass of AlCl3 = 27 + 35.5(3)
= 27 + 106.5
= 133.5g/mol
Using mole = mass/molar mass
mole = 4.5/133.5
mole = 0.034moles
number of atoms in a substance (nA) = number of moles (n) × Avagadros number or constant (6.02 × 10^23 atoms)
nA of AlCl3 = 0.034 × 6.02 × 10^23
nA = 0.2047 × 10^23
nA = 2.047 × 10^22 atoms.