Final answer:
To calculate the mass of fluorine in 425 grams of CaF2, one must determine the fraction of fluorine in CaF2 and multiply this by the mass of the sample, resulting in 206.76 grams of fluorine.
Step-by-step explanation:
Calculating the Mass of Fluorine in CaF2
To find out how many grams of fluorine are in 425 grams of CaF2, we need to use the molar mass of CaF2 and the molar masses of calcium (Ca) and fluorine (F). The formula mass of CaF2 is 78.08 amu. In one formula unit of CaF2, there is one calcium atom and two fluorine atoms. The molar mass of calcium is 40.08 amu, and the molar mass of each fluorine atom is 19.00 amu.
Firstly, calculate the fraction of fluorine in CaF2:
Molar mass of Ca: 1 × 40.08 = 40.08 amu
Molar mass of F: 2 × 19.00 = 38.00 amu
Total molar mass of CaF2: 40.08 amu + 38.00 amu = 78.08 amu
The fraction of fluorine is:
(38.00 amu fluorine)/(78.08 amu CaF2) = 0.4865 (fraction of fluorine in CaF2)
Multiply this fraction by the total mass of CaF2 to find the mass of fluorine in the sample:
(425 grams CaF2) × 0.4865 (fraction of F) = 206.76 grams of F
Thus, the sample of CaF2 contains 206.76 grams of fluorine.