Final answer:
To determine the number of moles in 3.43 × 10²³ formula units of CaBr₂, divide the number of formula units by Avogadro's number. The molar mass of CaBr₂ is needed to calculate the number of moles.
Step-by-step explanation:
To determine the number of moles in 3.43 × 10²³ formula units of CaBr₂, you need to use the molar mass of CaBr₂ and Avogadro's number.
Step 1: Calculate the molar mass of CaBr₂. The atomic mass of Ca is 40.08 g/mol and the atomic mass of Br is 79.90 g/mol. So, the molar mass of CaBr₂ is 40.08 g/mol + 2 * 79.90 g/mol = 199.88 g/mol.
Step 2: Divide the number of formula units given (3.43 × 10²³) by Avogadro's number (6.022 × 10²³) to get the number of moles. Therefore, the number of moles in 3.43 × 10²³ formula units of CaBr₂ is (3.43 × 10²³) / (6.022 × 10²³) = 0.570 moles.