The fraction of gas phase molecules is calculated by the division of final pressure to the initial pressure.
Fraction = [tex]\frac{P_{final}}{P_{initial}}[/tex] (1)
Here, initial pressure = 1.0 atm
final pressure = [tex]1.0\times 10^{-10} torr[/tex]
First, convert torr into atm
1 atm = 760 torr
final pressure = [tex]\frac{1.0\times 10^{-10}}{760}[/tex]
= [tex]1.316\times 10^{-13}atm[/tex]
Now, put the value of initial and final pressure in formula (1)
Fraction = [tex]\frac{1.316\times 10^{-13}atm}{1.0 atm}[/tex]
= [tex]1.316\times 10^{-13}[/tex]
Thus, fraction of the gas phase molecules = [tex]1.316\times 10^{-13}[/tex] [tex]\simeq 1.3\times 10^{-13}[/tex]
