OCR B (salters) A-level Chemistry paper 2 unofficial mark scheme (12/6/18)

Watch
brotherteresa256
Badges: 6
Rep:
?
#1
Report Thread starter 1 year ago
#1
Just posting questions that I can remember
Group two carbonate and acid added: HCl and BaCO3 converted to BaCl2
One of the pH questions was 4.2 I think
Concentration of HCl was 1.6x10-4 I think
Ionisation enthalpy was Mg(g) -> Mg1+(g) + e-
pH of NaOH/HCl was 10
For question about spectroscopic techniques I put H and C NMR both for the fact there are different environments involved
2As3+ + 3H2S -> As2S3 + 3H2
2As2O3 + 12H+ -> 2AsH3 + 6H2O

First question, Enthalpy of Solution was +4?? Or +47??

Cyclohexene provides evidence that Benzene has a deloclaised ring and the energy is less than three times the amount of the enthalpy of hydrogeneation of cyclohexene.
Cyclohexene and bromine - electrophilic addition
Benzene and bromine is electrophilic substitiution

Co2 is Linear

Sulfur forms disulfide bridges on proteins in the tertiary structure


More will be added over time
0
reply
Amanpreet1
Badges: 7
Rep:
?
#2
Report 1 year ago
#2
First question, Enthalpy of Solution was +4
2As3+ + 3H2S -> As2S3 + 3H2

Cyclohexene provides evidence that Benzene has a deloclaised ring and the energy is less than three times the amount of the enthalpy of hydrogeneation of cyclohexene.
Cyclohexene and bromine - electrophilic addition
Benzene and bromine is electrophilic substitiution

Co2 is Linear

Sulfur forms disulfide bridges on proteins in the tertiary structure
1
reply
Yoo18
Badges: 7
Rep:
?
#3
Report 1 year ago
#3
What did everyone put for the rate equation question of hydrogen peroxide ?
0
reply
black1blade
Badges: 19
Rep:
?
#4
Report 1 year ago
#4
Fairly sure it was 11 and a lot of people made a mistake, not considering the fact that volume was doubled therefore conc halved. So 20cm^3 5x10^-3 moldm^-3 HCl and 20cm^3 1x10^-2 moldm^-3 NaOH so you've got 1x10^-4 moles of OH- left after they react, therefore conc divide by 0.04dm^3 is 2.5x10^-3 moldm^-3. Therefore H+ conc is 4x10^-12 therefore pH 11.4. Maybe I just misread the question and the amounts involved, wouldn't be the first time XD.
1
reply
catfanny
Badges: 14
Rep:
?
#5
Report 1 year ago
#5
(Original post by black1blade)
Fairly sure it was 11 and a lot of people made a mistake, not considering the fact that volume was doubled therefore conc halved. So 20cm^3 5x10^-3 moldm^-3 HCl and 20cm^3 1x10^-2 moldm^-3 NaOH so you've got 1x10^-4 moles of OH- left after they react, therefore conc divide by 0.04dm^3 is 2.5x10^-3 moldm^-3. Therefore H+ conc is 4x10^-12 therefore pH 11.4. Maybe I just misread the question and the amounts involved, wouldn't be the first time XD.
I did that too!
0
reply
Yoo18
Badges: 7
Rep:
?
#6
Report 1 year ago
#6
(Original post by black1blade)
Fairly sure it was 11 and a lot of people made a mistake, not considering the fact that volume was doubled therefore conc halved. So 20cm^3 5x10^-3 moldm^-3 HCl and 20cm^3 1x10^-2 moldm^-3 NaOH so you've got 1x10^-4 moles of OH- left after they react, therefore conc divide by 0.04dm^3 is 2.5x10^-3 moldm^-3. Therefore H+ conc is 4x10^-12 therefore pH 11.4. Maybe I just misread the question and the amounts involved, wouldn't be the first time XD.
I did this too but I got 11.6 or something like that
0
reply
Sasha199910
Badges: 3
Rep:
?
#7
Report 1 year ago
#7
I got 7.5 for the pH of the hcl and naoh solution, and also ****ed the bond angle of trimethylarsine
0
reply
catfanny
Badges: 14
Rep:
?
#8
Report 1 year ago
#8
(Original post by Sasha199910)
I got 7.5 for the pH of the hcl and naoh solution, and also ****ed the bond angle of trimethylarsine
What did u put for the bond angle? I put 107 i think
1
reply
Alexandra00
Badges: 5
Rep:
?
#9
Report 1 year ago
#9
(Original post by catfanny)
What did u put for the bond angle? I put 107 i think
same I got 107
1
reply
M-AR
Badges: 3
Rep:
?
#10
Report 1 year ago
#10
(Original post by brotherteresa256)
Just posting questions that I can remember
Group two carbonate and acid added: HCl and BaCO3 converted to BaCl2
One of the pH questions was 4.2 I think
Concentration of HCl was 1.6x10-4 I think
Ionisation enthalpy was Mg(g) -> Mg1+(g) + e-
pH of NaOH/HCl was 10
For question about spectroscopic techniques I put H and C NMR both for the fact there are different environments involved
2As3+ + 3H2S -> As2S3 + 3H2
2As2O3 + 12H+ -> 2AsH3 + 6H2O

First question, Enthalpy of Solution was +4?? Or +47??

Cyclohexene provides evidence that Benzene has a deloclaised ring and the energy is less than three times the amount of the enthalpy of hydrogeneation of cyclohexene.
Cyclohexene and bromine - electrophilic addition
Benzene and bromine is electrophilic substitiution

Co2 is Linear

Sulfur forms disulfide bridges on proteins in the tertiary structure


More will be added over time
Am I the only one who forgot to put a sign in front of the enthalpy of solution? I just put 4
0
reply
joshbryanscre
Badges: 7
Rep:
?
#11
Report 1 year ago
#11
(Original post by brotherteresa256)
Just posting questions that I can remember
Group two carbonate and acid added: HCl and BaCO3 converted to BaCl2
One of the pH questions was 4.2 I think
Concentration of HCl was 1.6x10-4 I think
Ionisation enthalpy was Mg(g) -> Mg1+(g) + e-
pH of NaOH/HCl was 10
For question about spectroscopic techniques I put H and C NMR both for the fact there are different environments involved
2As3+ + 3H2S -> As2S3 + 3H2
2As2O3 + 12H+ -> 2AsH3 + 6H2O

First question, Enthalpy of Solution was +4?? Or +47??

Cyclohexene provides evidence that Benzene has a deloclaised ring and the energy is less than three times the amount of the enthalpy of hydrogeneation of cyclohexene.
Cyclohexene and bromine - electrophilic addition
Benzene and bromine is electrophilic substitiution

Co2 is Linear

Sulfur forms disulfide bridges on proteins in the tertiary structure


More will be added over time
you wouldnt have the OZ end of module test would you?
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

What factors affect your mental health the most right now? (select all that apply)

Lack of purpose or routine (276)
15.5%
Uncertainty around my education (279)
15.67%
Uncertainty around my future career prospects (177)
9.94%
Isolating with family (126)
7.07%
Lack of support system (eg. Teachers, counsellors) (79)
4.44%
Lack of exercise/ability to be outside (149)
8.37%
Loneliness (176)
9.88%
Financial worries (72)
4.04%
Concern about myself or my loved ones getting ill (163)
9.15%
Exposure to negative news/social media (126)
7.07%
Lack of real life entertainment (eg. cinema, gigs, restaurants) (158)
8.87%

Watched Threads

View All