Final answer:
To determine the number of oxygen atoms in 6.50 g of Al₂(SO₄)₃, the substance's molar mass is used to convert the mass to moles. This quantity is then multiplied by Avogadro's number and the number of oxygen atoms per mole of the substance, yielding a result of 1.37 × 10²² oxygen atoms.
Step-by-step explanation:
To find out how many oxygen atoms are in 6.50 g of Al₂(SO₄)₃, we must first determine the molar mass of Al₂(SO₄)₃ to convert grams to moles. The molar mass of Al₂(SO₄)₃ is derived by adding the molar masses of its constituent elements: 2xAl (26.98 g/mol), 3xS (32.07 g/mol), and 12xO (16.00 g/mol). The molar mass of Al₂(SO₄)₃ is then calculated to be approximately 342.15 g/mol.
Next, we use the molar mass to convert 6.50 g of Al₂(SO₄)₃ to moles:
(6.50 g / 342.15 g/mol) = 0.0190 moles of Al₂(SO₄)₃
Since each formula unit of Al₂(SO₄)₃ contains 12 oxygen atoms, we multiply the number of moles by Avogadro's number (6.022 × 10²³ atoms/mol) and by 12:
(0.0190 moles) × (6.022 \u00d7 10²³ atoms/mol) × (12 oxygen atoms/mole Al₂(SO₄)₃) = 1.37 × 10²² oxygen atoms
We express our final answer in scientific notation with two decimal places: 1.37 × 10²² oxygen atoms.