Question

A and B are two gases that are mixed together; 2.50 mol A is mixed with 0.85 mol B. If the final pressure of the mixture is 1.75 atm, what are the partial pressures of A and B?

Answer 1

partial pressure of A= 1.31atm
partial pressure of B= 0.44 atm

just did this chem assignment on edgenuty so i know this is right

Answer 2

Answer : Partial pressure of gas A is 1.31 atm and that of gas B is 0.44 atm.

Explanation :

The partial pressure of a gas in a mixture can be calculated as

`P_(i)= X_(i)* P`

Where Pi is the partial pressure ; Xi is mole fraction and P is the total pressure of the mixture.

Therefore we have
,

`P_(A) = X_(A) * P`

`P_(B) = X_(B) * P`

Let us find
`X_(A)` and
`X_(B)`

`X_(A) = (mol A)/(total moles) = (2.50 mol)/((2.50 + 0.85)mol) = (2.50 mol)/(3.35mol) = 0.746`

`X_(B) = (mol B)/(total moles) = (0.85 mol)/((2.50 + 0.85)mol) = (0.85 mol)/(3.35mol) = 0.254`

Total pressure P is given as 1.75 atm.

Let us plug in the mole fractions and P values to find partial pressures of gas A and B.

`P_(A) = X_(A) * P`

`P_(A) = 0.746 * 1.75`

`P_(A) =1.31 atm`

Partial pressure of gas A is 1.31 atm

`P_(B) = X_(B) * P`

`P_(B) = 0.254 * 1.75`

`P_(A) = 0.44 atm`

Partial pressure of gas B is 0.44 atm.

Therefore, partial pressures of gas A and B are 1.31 atm and 0.44 atm respectively.