The Student Room Group
<a https://www.thestudentroom.co.uk/showthread.php?t=7467335'> Year 12s: what will be the first way you research your future options? >>
<a https://www.thestudentroom.co.uk/showthread.php?t=7467335'> Year 12s: what will be the first way you research your future options? >>
<a https://www.thestudentroom.co.uk/showthread.php?t=7467335'> Year 12s: what will be the first way you research your future options? >>

AS level chemistry help pls

So for this question i managed to do pv=nrt which i got 174

yet there's another answer underneath this which says 69.6

why is that there , what does it mean and how do i figure it out

thanks :smile:
chemistry.png132.3KB
what do you mean answer underneath? :smile:
Original post by mansnothot
what do you mean answer underneath? :smile:


where did 69.6 come from

chemistry 2.png
Original post by Ray_Shadows
So for this question i managed to do pv=nrt which i got 174

yet there's another answer underneath this which says 69.6

why is that there , what does it mean and how do i figure it out

thanks :smile:


I don't know what you did, but I also used pV=nRTpV = nRT and got 7.59 mol.

These moles are for both nitrogen monoxide and steam, so find the mole fraction of NO by dividing the stoichiometric molar ratio of NO by the total stoichiometric molar ratio (this would be 410\frac{4}{10}), and then multiply the moles of gas by the mole fraction; I got 3.04 mol of NO.

Could you please explain what you did? I don't know if I'm right by the way, so I'm not saying you're wrong :smile:
(edited 5 years ago)
Original post by Kian Stevens
I don't know what you did, but I also used pV = nRT[\latex] and got 7.59 mol.

These moles are for both nitrogen monoxide and steam, so find the mole fraction by dividing the stoichiometric molar ratio of NO by the total stoichiometric molar ratio (\frac{4}{10}[\latex], and then multiply the moles of gas by the mole fraction to get 3.04 mol of NO.

Could you please explain what you did? I don't know if I'm right by the way, so I'm not saying you're wrong :smile:


i did

n=(100000 x 4.31)/(8.31 x 298)

which was 174 (as shown on the mark scheme)

where did the answer underneath it (69.6) come from
So basically the moles of gas produced in reaction 1 in total is 10. Thats where the 174 comes from. You want 4 moles of this as this is moles of NO. So divide 174 by 10 and x 4.
Original post by mansnothot
So basically the moles of gas produced in reaction 1 in total is 10. Thats where the 174 comes from. You want 4 moles of this as this is moles of NO. So divide 174 by 10 and x 4.


oh ok then , that makes sense

i did it the other way around , thank you very much
Original post by Ray_Shadows
oh ok then , that makes sense

i did it the other way around , thank you very much


Meh, I did the exact same thing as you but my calculator gave me the wrong answer... Sorry about that :tongue:
Original post by Kian Stevens
Meh, I did the exact same thing as you but my calculator gave me the wrong answer... Sorry about that :tongue:


it's fine i got my answer , thanks anyway :smile:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you