Final answer:
The number of moles in 3.50 × 10²³ formula units of BaCl₂ is calculated by dividing the number of formula units by Avogadro's number, yielding approximately 0.58 moles, which is closest to option (a) 0.5 moles.
Step-by-step explanation:
To determine the number of moles in 3.50 × 10²³ formula units of BaCl₂, you need to use Avogadro's number, which is 6.022 × 10²³ formula units per mole. By dividing the number of given formula units by Avogadro's number, you can find the number of moles.
Number of moles = (Number of formula units) / (Avogadro's number)
Number of moles = (3.50 × 10²³) / (6.022 × 10²³ moles⁻¹)
Number of moles = 0.58 moles
The value 0.58 does not exactly match any of the answer choices given (a) 0.5 moles (b) 1 mole (c) 2 moles (d) 3 moles, therefore there might be a typo in the answer choices or in the question. However, the closest available answer to the actual value of 0.58 moles would be (a) 0.5 moles.