Final answer:
The correct number of formula units of FeF3 in 24.0 grams is 8.91 x 10^22, which is none of the provided answers but closest to option A.
Step-by-step explanation:
The question is asking for the number of formula units of FeF3 (iron(III) fluoride) in 24.0 grams of the substance. To find this, we need to use Avogadro's number (6.022 x 1023 formula units/mol) and the molar mass of FeF3. The formula mass of FeF3 is given as 162.2 amu, meaning its molar mass is 162.2 g/mol. By dividing the mass of the sample by the molar mass, we can find the number of moles of FeF3.
First, calculate the moles of FeF3:
Number of moles = Mass ÷ Molar mass
24.0g FeF3 ÷ 162.2g/mol FeF3 = 0.148 moles of FeF3
Next, calculate the number of formula units:
Number of formula units = Number of moles x Avogadro's number
0.148 moles FeF3 x 6.022 x 1023 formula units/mol = 8.91 x 1022 formula units
While none of the provided answers (A. 1.27 x 1023 formula units, B. 0.2105 formula units, C. 24.0 formula units, D. 113.85 formula unit) match the correct calculation, it is nearest to option A. It could be a typographical error in the answers or in the formula mass provided for FeF3.