Answer:
3.93 × 10²¹ molecules
Step-by-step explanation:
Convert 1.98 grams of PbSO₄ to molecules.
Step 1: Given data
Mass of PbSO₄: 1.98 g
Step 2: Calculate the number of moles corresponding to 1.98 g of PbSO₄
The molar mass of PbSO₄ is 303.26 g/mol.
1.98 g × 1 mol/303.26 g = 6.53 × 10⁻³ mol
Step 3: Calculate the number of molecules in 6.53 × 10⁻³ moles of PbSO₄
To convert moles to molecules, we need a conversion factor: Avogadro's number. There are 6.02 × 10²³ molecules of PbSO₄ in 1 mole of molecules of PbSO₄.
6.53 × 10⁻³ mol × 6.02 × 10²³ molecules/1 mol = 3.93 × 10²¹ molecules