Understanding the Concept

* Mole: A mole is a unit of measurement for the amount of substance. It's like a "dozen" for atoms or molecules. One mole contains 6.022 x 10^23 particles (Avogadro's number).

* Formula Unit: A formula unit represents the simplest ratio of ions in an ionic compound. In the case of CaCl2, one formula unit consists of one calcium ion (Ca²⁺) and two chloride ions (Cl⁻).

Calculation

1. Start with the given moles: You have 2.50 moles of CaCl2.

2. Use Avogadro's number: Multiply the number of moles by Avogadro's number (6.022 x 10^23 formula units/mole) to find the number of formula units:

2.50 moles CaCl2 * (6.022 x 10^23 formula units/mole) = 1.51 x 10^24 formula units

Answer: There are 1.51 x 10^24 formula units present in 2.50 moles of CaCl2.