Question

What fraction of the gas phase molecules initially present for 1.0 atm in the chamber are present at 1.0×10−10 torr?

Answer 1

The fraction of gas phase molecules is calculated by the division of final pressure to the initial pressure.

Fraction =
`(P_(final))/(P_(initial))` (1)

Here, initial pressure = 1.0 atm

final pressure =
`1.0* 10^(-10) torr`

First, convert torr into atm

1 atm = 760 torr

final pressure =
`(1.0* 10^(-10))/(760)`

=
`1.316* 10^(-13)atm`

Now, put the value of initial and final pressure in formula (1)

Fraction =
`(1.316* 10^(-13)atm)/(1.0 atm)`

=
`1.316* 10^(-13)`

Thus, fraction of the gas phase molecules =
`1.316* 10^(-13)`
`\simeq 1.3* 10^(-13)`