Question

A 250 mL flask initially contains argon at a pressure of 2.0 atm. Neon is added to the flask until the total pressure reaches 5.0 atm. What is the mole fraction of neon in the final mixture

Answer 1

Answer: The mole fraction of neon in the final mixture is 0.6

Step-by-step explanation:

According to Dalton's law, the total pressure is the sum of individual pressures.

`p_(total)=p_A+p_B`

Given :
`p_(total)` =total pressure of gases = 5.0 atm

`p_(Ar)` = partial pressure of argon = 2.0 atm

`p_(Ne)` = partial pressure of Neon = ? atm

`5.0atm=2.0atm+p_(Ne)`

`p_(Ne)=3.0atm`

According to Raoults law, the partial pressure of a gas is equal to its mole fraction mulitiplied by the total pressure.

`p_(Ne)=\chi_(Ne)* p_(total)`

`\chi_(Ne)` = mole fraction of Neon

`3.0=\chi_(Ne)* 5.0`

`\chi_(Ne)=0.6`

Thus mole fraction of neon in the final mixture is 0.6