1. Find the molar mass of CaCl₂:
* Ca: 40.08 g/mol
* Cl: 35.45 g/mol (x 2 for two chlorine atoms)
* Total molar mass = 40.08 + (35.45 x 2) = 110.98 g/mol
2. Convert grams to moles:
* Moles = (grams) / (molar mass)
* Moles = 654.5 g / 110.98 g/mol
* Moles ≈ 5.89 mol
3. Use Avogadro's number to find the number of molecules:
* Avogadro's number = 6.022 x 10²³ molecules/mol
* Number of molecules = (moles) x (Avogadro's number)
* Number of molecules ≈ 5.89 mol x 6.022 x 10²³ molecules/mol
* Number of molecules ≈ 3.55 x 10²⁴ molecules
Therefore, there are approximately 3.55 x 10²⁴ molecules in 654.5 grams of calcium chloride.
