Question

The carbon monoxide for use in the production of methanol may be formed by reacting
carbon dioxide with hydrogen.

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20(9701)/9701_s13_qp_23.pdf
Question 2 b)
Please ppl help!! i totally don't get it :(
Thank you!

Answer 1

here is the screenshot of the question

Answer 2

@Kainui

Answer 3

@aaronq

Answer 4

yes u're already on the question Mr.Kainui :D

Answer 5

ok ok

fine u complete the table.. !!!

initial - 0.7 0.7 0.3 0.3
no
reacted - (-x) (-x) +x +x

no
remaning (0.7-x) (0.7-x) 0.3+x 0.3+x

now use Kc formula.. tadaaa :D

Answer 6

and u think we didn't know the earlier part? -_-
It IS the Kc part we don't get!!

Answer 7

What we don't get is why x is = to 0.25

Answer 8

kc = [H2][Co2]/ [H20][CO]
substitude the values..

Answer 9

Oh lol.. use calculator xD

Answer 10

its a quadratic equation.. solve it :O

Answer 11

dear =_= @Mashy Kc= [product]/[reactant]
not the opposite

Answer 12

yea yea.. i took the reverse reaction :P.. sorry!

Answer 13

@Mashy the problem is that we cant solve it, we do know how to do it but the solving part is confusing T_T

Answer 14

take square root on both sides

Answer 15

so u get

(0.3 + x)/(0.7 -x ) = +1.2 0r -1.2
now solve them :P

Answer 16

omg im so stupid @Mashy
this square root was the only thing that didnt let us get the ans =_=

Answer 17

well.. in this case yea..
but in general.. u would expand it .. and then solve the quadratic equation ..

Answer 18

i dont get the answer when i do it as quadratic equation

Answer 19

you should.. show me ur work!

Answer 20

here is the work with taking root square as u told me

Answer 21

the quadratic one, its messy tho, i hope u get it

Answer 22

Your final equation is wrong..

0.7056 - 0.09 = 0.6156
you have put 0.6136 :P or thats what it looks like to me

if you solve that equation.. u get exactly 0.245 = 0.25 as one of the sane solution
other solution u can neglect!

Answer 23

i dont get it, i dunno how u r doing it but i have no idea how to do it T_T

Answer 24

use
\[ax^2 + bx + c = 0 \\ x = \frac{-b+-\sqrt{b^2-4.a.c}}{2a}\]

Answer 25

i know it =_=

Answer 26

so just plug in the values!

Answer 27

@Mashy look i did it this time till the end, and yes i do get the answer
but i have x1 and x2
how am i supposed to know that i should use x2 not x1?

Answer 28

cause x1 is absurd.. u started with 0.7 moles right?.. so you can't have 5.7 as the answer

u get 5.7 even when u take square root
remember root of 1.44 = + 1.2 or -1.2
so if u take -1.2 and do it, then u would get that 5.7 (which u skipped due to the joy of getting the answer :P )

Answer 29

lmao ok hhhh :D