Question

periodic table
calcium fluoride (caf₂) is a major component in human teeth. calculate the percent composition of calcium fluoride.
a 48.7% ca, 51.3% f
b 40.1% ca, 59.9% f
c 33.3% ca, 66.7% f
d 51.3% ca, 48.7% f

Explanation:

Step1: Calculate the molar mass of \(CaF_2\)

The atomic mass of \(Ca = 40.08\space g/mol\), and the atomic mass of \(F=19.00\space g/mol\).
The molar mass of \(CaF_2\), \(M = 40.08+(2\times19.00)=40.08 + 38.00=78.08\space g/mol\)

Step2: Calculate the mass percentage of \(Ca\)

The mass percentage of \(Ca\), \(w_{Ca}=\frac{40.08}{78.08}\times100\%\approx51.3\%\)

Step3: Calculate the mass percentage of \(F\)

The mass percentage of \(F\), \(w_{F}=\frac{38.00}{78.08}\times100\%\approx48.7\%\)

Answer:

D. \(51.3\%\text{ Ca}, 48.7\%\text{ F}\)