HELP! Chemistry emergency :( (1 Viewer)

lucywills24

New Member
Joined
Jan 3, 2021
Messages
8
Gender
Female
HSC
2022
So I haven’t studied for chem all summer holidays and I have forgotten so much content, so I have to start back at mod 5. Can anyone please help me with this question, the answer is D but I can’t figure out why. Thanks 😊

79B89FFC-CE94-4120-A586-EEB93DCE32D1.jpeg
 

jazz519

Moderator
Moderator
Joined
Feb 25, 2015
Messages
1,955
Location
Sydney
Gender
Male
HSC
2016
Uni Grad
2021
So I haven’t studied for chem all summer holidays and I have forgotten so much content, so I have to start back at mod 5. Can anyone please help me with this question, the answer is D but I can’t figure out why. Thanks 😊

View attachment 34828
For the 1st reaction:

K = [O2] [HCL]^4 / [Cl2]^2 [H2O]^2
4.0 x 10^(-4) = [O2] [HCL]^4 / [Cl2]^2 [H2O]^2


For the 2nd reaction:
K = [Cl2] [H2O] / [O2]^(1/2) [HCL]^2


We need to change the first expression into the 2nd one. This would involve flipping the fraction i.e.

1 / (4x10^-4) = [Cl2]^2 [H2O]^2 / [O2] [HCL]^4

and then taking a square root

sqrt( 1 / 4 x 10^-4) = [Cl2] [H2O] / [O2]^(1/2) [HCL]^2


Sub that into a calculator and it will give the answer
 

lucywills24

New Member
Joined
Jan 3, 2021
Messages
8
Gender
Female
HSC
2022
For the 1st reaction:

K = [O2] [HCL]^4 / [Cl2]^2 [H2O]^2
4.0 x 10^(-4) = [O2] [HCL]^4 / [Cl2]^2 [H2O]^2


For the 2nd reaction:
K = [Cl2] [H2O] / [O2]^(1/2) [HCL]^2


We need to change the first expression into the 2nd one. This would involve flipping the fraction i.e.

1 / (4x10^-4) = [Cl2]^2 [H2O]^2 / [O2] [HCL]^4

and then taking a square root

sqrt( 1 / 4 x 10^-4) = [Cl2] [H2O] / [O2]^(1/2) [HCL]^2


Sub that into a calculator and it will give the answer
Thank you so much that really helped, I appreciate your response! I was just wondering, why do you need to square root for the answer?
 

jazz519

Moderator
Moderator
Joined
Feb 25, 2015
Messages
1,955
Location
Sydney
Gender
Male
HSC
2016
Uni Grad
2021
Thank you so much that really helped, I appreciate your response! I was just wondering, why do you need to square root for the answer?
Because if you at the terms like [H2O]^2 which changes to [H2O] the only way to get rid of the power on the H2O is by taking a square root
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top