Question

Calculate the number of aluminum atoms in 3.42 g of Al₂(SO₄)₃. The molar mass of Al₂(SO₄) is 342.14 g/mol.

o 6.02 x 10²⁵ atoms
o 6.02 x 10²¹ atoms
o 1.81 x 10²² atoms
o 1.20 x 10²² atoms
o 3.01 x 10²¹ atoms

Answer 1

To find the number of aluminum atoms in 3.42 g of Al₂(SO₄)₃, convert the mass to moles using the molar mass, then multiply the moles of aluminum by Avogadro's number to get approximately 1.20 × 10²² atoms.

Step-by-step explanation:

To calculate the number of aluminum atoms in 3.42 g of Al2(SO4)3, first you need to know how many moles of the compound you have. Using the molar mass of Al2(SO4)3, which is 342.14 g/mol, you can calculate the moles of compound:

Number of moles = mass (g) / molar mass (g/mol) = 3.42 g / 342.14 g/mol = 0.01 mol

Since each formula unit of Al2(SO4)3 contains 2 atoms of aluminum, you will have 0.02 mol of aluminum atoms.

Now, convert moles of aluminum atoms to number of atoms using Avogadro's number (6.022 × 1023 atoms/mol):

Number of aluminum atoms = 0.02 mol × 6.022 × 1023 atoms/mol = 1.2044 × 1022 atoms

The closest answer to our result is 1.20 × 1022 atoms.