How many formula units are in 302.48 grams of zinc chloride?

To find out how many formula units are in 302.48 grams of zinc chloride (ZnCl₂), we need to perform the following steps:

Step 1: Calculate the molar mass of ZnCl₂. - The molar mass of zinc (Zn) is approximately 65.38 grams/mole. - The molar mass of chlorine (Cl) is approximately 35.45 grams/mole. Since there are two chlorine atoms in zinc chloride, we multiply this by 2. - Add the molar masses together to get the molar mass of ZnCl₂: Molar mass of ZnCl₂ = (1 × 65.38) + (2 × 35.45) = 65.38 + 70.90 = 136.28 grams/mole.

Step 2: Convert the mass of ZnCl₂ to moles. - Use the formula: Moles = Mass / Molar mass. Moles of ZnCl₂ = 302.48 grams / 136.28 grams/mole ≈ 2.219 moles.

Step 3: Convert the moles of ZnCl₂ to formula units. - 1 mole of any substance contains Avogadro's number of formula units, which is approximately 6.022 × 10²³ formula units/mole. - Multiply the moles of ZnCl₂ by Avogadro's number to get the number of formula units: Formula units = Moles × Avogadro's number = 2.219 moles × 6.022 × 10²³ formula units/mole ≈ 1.336 × 10²⁴ formula units.

Therefore, there are approximately 1.336 × 10²⁴ formula units of ZnCl₂ in 302.48 grams.