Chem Question (1 Viewer)

[undalay]

the output of a diesel generator, which contains a mixture of CO2 and H2O gases, is collected in a sealed vessel at 447K. as the mixture cools to 298K, the pressure falls from 3.0 atm to .8 atm.

What is the ratio of CO2 to H2O?

 

[xiao1985]

I shall assume gas does not increase in pressure when heated up (which is, obviously, incorrect) then the change of pressur eis 2.2 atm... and the change of pressure would be solely due to H2O, since H2O condenses at low temperature... so the ratio will be 2.2/0.8 = 11/4

in reality, you should use nRT = PV to solve this question... however, i would doubt in hsc, you would have learnt such equation...

 

[undalay]

Yeah i did use that PV = nRT and got somethign similar

However the answer is 3:2.

I don't understand how ...

Question is listed on the 2006 Chem olympiad NQE Q14

 

[Forbidden.]

never seen questions like these appear in HSC exams that are related to our current syllabus

Yeah i did use that PV = nRT and got somethign similar

However the answer is 3:2.

I don't understand how ...

Question is listed on the 2006 Chem olympiad NQE Q14

so its the chem olympiad.

i dont like extra-curricular stuff sometimes

 

[undalay]

dw guys i finally got it -__- lol

PV = nRT
3 = n 447
n = .0817
PV = nRT
.8 = n 298
n = .0327 (amount of CO2)
.0817 - .0327 = .049 ( amount of O2)
Time both by some nice 10's

32.7 = 49
approximately
33 = 50
approximately
2:3


It's not hard sigh took me ages lol

 

[HappyFeet]

I am not sure what you mean but all I did was assume that all the water has condensed back into a liquid at 298K and that 0.8 atm is from the carbon dioxide so you can calculate the moles of carbon dioxide and hence the moles of water.

 

[xiao1985]

re above: did you get the same ansewr though?

 

[TesseracT22]

Something in your working is a bit wierd coz when i do it i get exactly the correct ratio but yours are approx?