Question

At 20 degrees Celsius the vapor pressure of benzene (C6H6) is 75 torr, and that of toluene (C7H8) is 22 torr. Assume that benzene and toluene form an ideal solution.

a) What is the composition in mole fractions of a solution that has a vapor pressure of 45 torr at 20 degrees celsius.

b) What is the mole fraction of benzene in the vapor above the solution described in part (a)?

Why is the mole fraction of Toluene 1-x?

Answer 1

lies and slander!
(slander is also known as slendermen)

Answer 2

Useless responses are useless

Answer 3

@dumbcow can u help dall out?

Answer 4

I would if i knew chem.. sorry

Answer 5

you are a great example of one bahrom.

Answer 6

OHHHHHHHHHHH!!

Answer 7

now could we get back to the slenderman dallbencaer?

Answer 8

I don't think this is using the ideal gas law, instead using roultz law: \(P_{tot}=x_ap_a+x_b+p_b...\)
Knowing that x_a+x_b = 1
they have all the information, so they should be able to do this.

for part b, they can find the vapor presure from benzene using the same formula. find the mole fraction by dividing by total pressure.

Answer 9

Raoult's Law states that for an ideal solution the partial vapor pressure of a component in solution is equal to the mole fraction of that component times its vapor pressure when pure

ok, let's make the mole fraction of benzene be X
therefore, the mole fraction of toluene must be 1-X

75X + 22(1-X) = 37
75X + 22 - 22X = 37
53X = 15
X = 15/53 for benzene = 0.28
for toluene the mole fraction would be (53-15)/53 or 38/53 = 0.72

Answer 10

ya I should read it again

Answer 11

thanks

Answer 12

where did you get your numbers from @igotreported

Answer 13

(a) What is the composition in mole fractions of a solution that has a vapor pressure of 40. torr at 20°C?
Let X be the mole fraction of benzene in this ideal solution. Thus 1-X is the mole fraction of toluene in this ideal solution.
The following is given:
75X + 22(1-X) = 40, or:
53X = 18, and X = 18/53.
Benzene's mole fraction is 18/53, and toluene's mole fraction is 35/53.

(b) What is the mole fraction of benzene in the vapor above the solution described in part (a)?
(75*18/53)/40 = 63.7%

Answer 14

brain

Answer 15

LIES AND SLANDER!!!!!!!!!!!

Answer 16

lies and slendermen abb!

Answer 17

I don't see where 37 came from!! This is all lies and slander!!

Answer 18

work the problem

Answer 19

let me read on raoult's law brb before I get slandered

Answer 20

somethings happening to my eyes when i lokk at your profile pic nina

Answer 21

i think your profile pic has a curse, no joking

Answer 22

okay I am done reading it

Answer 23

and?

Answer 24

i kinda hurried on the my answer so im not surprised if im wrong

Answer 25

I think you missed some big parts

Answer 26

let me read your solution first

Answer 27

okay whats your answer

Answer 28

I am curious @igotreported
where did you get 37?

Answer 29

i showed steps... you guys should look at the steps first.

Answer 30

yeah, that's what I'm wondering wehre the 37 came from. Lol

Answer 31

Shouldn't it be 45. Lol

Answer 32

okay thats not funny.... i dont understand why you wrote lol....

Answer 33

lol = losers occasionally leave

Answer 34

interesting.. except for i didnt see myself a loser occasionally leaving.... please explain

Answer 35

oh and btw,, thanks for the medal:)

Answer 36

LMAO I am still lost as to how you all know that the mole fraction of toluene = 1-X?

If Ptot = (Pa)(Xa)+(Pb)(Xb)
Ptot = 45
Pa = 75
Xa = mol benzene/mol benzene+mol toluene
Pb = 22
Xb = mol toluene/mol benzene+mol toluene
thus
45 = (75)(a/a+b)+(22)(b/a+b)
and i got nothing from here

where is 1 coming from? Lies and Slander I say =-P

Night peeps, thanks for helping

Answer 37

btw if I was a teacher, I would totally know how to do this =-P

Answer 38

your right