9. Suppose two gases in a container have a total pressure of 1.20 atm. What is the pressure of gas B if the partial pressure of gas A is 0.75 atm?

1 Answer
anor277
Jan 26, 2017

#P_B=0.45*atm#

Explanation:

Dalton's Law of partial pressure holds that in a gaseous mixture, the pressure exerted by a component is the same as the pressure it would exert if it ALONE occupied the container. The total pressure is the sum of the individual partial pressure.

i.e. #P_"Total"=P_1+P_2+P_3.........#

And here #P_"Total"=1.20*atm=P_A+P_B=0.75*atm+P_B#,

i.e. #P_B=1.20*atm-0.75*atm=??*atm.#

Note that we can use this law to access the number of moles of each gas, given that #P=(nRT)/V#,

i.e. #P_"Total"=(RT)/V{n_1+n_2+...........n_n}#, where #n_i# is the number of moles of gas #i#.

And we can show that:

#P_i/P_"Total"=n_i/n_"Total"#,

i.e. partial pressure is equivalent to mole fraction.

Related questions
See all questions in Partial Pressure
Impact of this question
17766 views around the world
You can reuse this answer
Creative Commons License