Answer:
0.018 grams
Explanation:
The number of moles (n) in such number of atoms of Aluminum must be calculated by dividing the number of atoms (nA) by Avagadro's number i.e.
n = nA ÷ 6.02 × 10^23atoms
The number of atoms of Aluminum in this question has been given as: 3.99 x 10^20 atoms.
n = 3.99 x 10^20 ÷ 6.02 × 10^23
n = 3.99/6.02 × 10^(20-23)
n = 0.663 × 10^-3
n = 0.000663moles
Next, we convert the mole value to mass in grams by using the formula;
mole = mass/molar mass
mass = mole × molar mass
Molar mass of Al = 27g/mol
mass (g) = 0.000663 × 27
mass = 0.0179
mass of Aluminum is 0.018grams
