Final answer:
The number of molecules in 923 grams of CaF2 is 7.12 x 1024 molecules.
Step-by-step explanation:
To determine how many molecules are in 923 grams of CaF2, we first need to calculate the number of moles of CaF2. The formula mass of CaF2 is given as 78.08 amu (atomic mass units), which is equivalent to 78.08 g/mol. Using dimensional analysis, we set up the calculation:
923 g CaF2 x (1 mol CaF2 / 78.08 g CaF2) = 11.82 moles of CaF2
Now, we use Avogadro's number, which is 6.022 x 1023 molecules/mol, to find the total number of molecules:
11.82 moles of CaF2 x (6.022 x 1023 molecules/mol) = 7.12 x 1024 molecules of CaF2