Answer: The number of molecules of ethinyl estradiol present in one pill are [tex]7.71\times 10^{16}[/tex]
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of ethinyl estradiol = 0.038 mg = [tex]3.8\times 10^-5}g[/tex] (Conversion factor: 1 g = 1000 mg)
Molar mass of ethinyl estradiol [tex](C_{20}H_{24}O_2)=[(20\times 12)+(24\times 1)+(2\times 16)]=296g/mol[/tex]
Putting values in above equation, we get:
[tex]\text{Moles of ethinyl estradiol}=\frac{3.8\times 10^{-5}g}{296g/mol}=1.28\times 10^{-7}mol[/tex]
According to mole concept:
1 mole of a compound contains [tex]6.022\times 10^{23}[/tex] number of molecules
So, [tex]1.28\times 10^{-7}mol[/tex] of ethinyl estradiol will contain = [tex](1.28\times 10^{-7}\times 6.022\times 10^{23})=7.71\times 10^{16}[/tex] number of molecules
Hence, the number of molecules of ethinyl estradiol present in one pill are [tex]7.71\times 10^{16}[/tex]
