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Edexcel A Level Chemistry 2019 Paper 1 Unofficial Mark Scheme

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Reply 60
Avatar for TM37
TM37
5
I put D
Original post by Munrhe
Amazing. Thank you. Did you remember last MS? C or D?
For the electron affinity did anyone get -73
Reply 62
Avatar for TomasD
TomasD
12
SAME!! haha
Original post by Stormragexox
alot of people were like it was easy an i was the only one who found it hard:frown:
That was to with the change of pH form 7 at 298K but something lower at a higher temperature. Since it is lower at a higher temp, the conc of H+ has increased, so equilibrium has shifted to the right. The reaction must therefore be endothermic
Original post by Shimo
I think endothermic as neutralisation is exothermic, so it has to be opposite, I think
Original post by mupsman2312
I felt like there were a few curveballs in that paper. Does anyone agree with these numerical answers?

Born-Haber: -2277 kJ mol^-1
Gibbs free energy: -1010 kJ mol^-1
Formation of H2S: -20.1 kJ mol^-1

(Orange solution of Cr2O7^2-)

Buffer ratio: 10.47 (6-marker)

Kp: 27.2 atm^-1
(Second experiment at less than 1000 K)

Initial pH: 2.98
Final pH: 12.55
(And choose cresol blue, I think it was)

Rate constant: 2.0 (1.95) * 10^-5 dm^3 mol^-1 s^-1

Let me know if you think any are wrong! :smile:

wrong paper mate
Reply 65
Avatar for TomasD
TomasD
12
Yes I think so
Original post by mdearing
For the electron affinity did anyone get -73
Reply 66
Avatar for TM37
TM37
5
I’m not sure we did the same exam, was your first question on the paper what are the number of protons, neutrons and electrons in oxygen-18
Original post by mupsman2312
I felt like there were a few curveballs in that paper. Does anyone agree with these numerical answers?

Born-Haber: -2277 kJ mol^-1
Gibbs free energy: -1010 kJ mol^-1
Formation of H2S: -20.1 kJ mol^-1

(Orange solution of Cr2O7^2-)

Buffer ratio: 10.47 (6-marker)

Kp: 27.2 atm^-1
(Second experiment at less than 1000 K)

Initial pH: 2.98
Final pH: 12.55
(And choose cresol blue, I think it was)

Rate constant: 2.0 (1.95) * 10^-5 dm^3 mol^-1 s^-1

Let me know if you think any are wrong! :smile:
Original post by Anna MacKinnon
That was to with the change of pH form 7 at 298K but something lower at a higher temperature. Since it is lower at a higher temp, the conc of H+ has increased, so equilibrium has shifted to the right. The reaction must therefore be endothermic

Yeah that sounds right - was it 1 Mark I’m hoping I haven’t lost too many cos of that question
Original post by TM37
I’m not sure we did the same exam, was your first question on the paper what are the number of protons, neutrons and electrons in oxygen-18

Did everyone put C for that question?
Reply 69
Avatar for Shimo
Shimo
16
Original post by mupsman2312
EDIT: Sorry, wrong exam board! :redface:

I felt like there were a few curveballs in that paper. Does anyone agree with these Thanks answers?

Born-Haber: -2277 kJ mol^-1
Gibbs free energy: -1010 kJ mol^-1
Formation of H2S: -20.1 kJ mol^-1

(Orange solution of Cr2O7^2-)

Buffer ratio: 10.47 (6-marker)

Kp: 27.2 atm^-1
(Second experiment at less than 1000 K)

Initial pH: 2.98
Final pH: 12.55
(And choose cresol blue, I think it was)

Rate constant: 2.0 (1.95) * 10^-5 dm^3 mol^-1 s^-1

Let me know if you think any are wrong! :smile:

please tell me this isn't Edexcel because I don't remember anything about a rate constant
What did you guys say for how an increase in oxygen affects the number of SO2 particles while referencing Kp? I said the reaction quotient would become smaller than Kp so the equilibrium would shift to the right so the number of particles decreases, does that sound correct?
Reply 71
Avatar for Shimo
Shimo
16
Original post by mdearing
For the electron affinity did anyone get -73


I did but I changed it because I'm fickle, shoulda just went with my gut
Reply 72
Avatar for TomasD
TomasD
12
Think what you said is right, its to do with Kp staying constant so eq shifts to the right to increase products to keep Kp constants
Original post by azozarmen
What did you guys say for how an increase in oxygen affects the number of SO2 particles while referencing Kp? I said the reaction quotient would become smaller than Kp so the equilibrium would shift to the right so the number of particles decreases, does that sound correct?
Reply 73
Avatar for TomasD
TomasD
12
A...?
Original post by jp.lk12
Did everyone put C for that question?
Original post by azozarmen
What did you guys say for how an increase in oxygen affects the number of SO2 particles while referencing Kp? I said the reaction quotient would become smaller than Kp so the equilibrium would shift to the right so the number of particles decreases, does that sound correct?

Yeah Q decreases due to increase in reactant so equilibrium shifts to right to re-establish Kp
Original post by TomasD
A...?

I put A too - don’t tell me I didn’t get Q1 right
didn't it have to be C because you would have 3 peaks at the far right of all the same height, and then 2 peaks to the left of the same height?
Original post by TomasD
A...?
Reply 77
Avatar for enzii44
enzii44
1
it was definitely A
Original post by TomasD
A...?
Reply 78
Avatar for TomasD
TomasD
12
This is the question 2 or 1b I cant remember, I put the one with 2 peaks on the left and 3 peaks (the one in the middle being taller) to the right - I think D
Original post by jp.lk12
didn't it have to be C because you would have 3 peaks at the far right of all the same height, and then 2 peaks to the left of the same height?
Reply 79
Avatar for laca123
laca123
6
think they are talking about the oxygen mc question. I put A for the oxygen one btw
Original post by jp.lk12
didn't it have to be C because you would have 3 peaks at the far right of all the same height, and then 2 peaks to the left of the same height?

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