Answer:
4.3 × 10²¹ atoms
Explanation:
Step 1: Calculate the moles corresponding to 0.24 g of CaCO₃
The molar mass of CaCO₃ is 100.09 g/mol.
0.24 g × (1 mol/100.09 g) = 2.4 × 10⁻³ mol
Step 2: Calculate the moles of oxygen in 2.4 × 10⁻³ moles of CaCO₃
The molar ratio of CaCO₃ to O is 1:3. The moles of O are 3/1 × 2.4 × 10⁻³ mol = 7.2 × 10⁻³ mol
Step 3: Calculate the number of O atoms in 7.2 × 10⁻³ moles of O
We will use Avogadro's number: there are 6.02 × 10²³ atoms of O in 1 mole of atoms of O.
7.2 × 10⁻³ mol × (6.02 × 10²³ atoms/1 mol) = 4.3 × 10²¹ atoms
