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AS Chemistry 2016 Unofficial Mark scheme

Alright I've put together a couple questions I remember from the exam and the answers, put through your questions or answers you dont agree with!

1.) chromium ion, 1s2 2s2 2p6 3s2 3p6 3d3
2.)aluminium 1s2 2s2 2p6 3s2 3p1
which ion has the same structure as krypton with a 2+ charge- strontium
which compound has a ion with 2+ from argon and 3- from argon- Ca3P2
bromine mass spectrum- 50% at 158 and 50% at 162
5 marks on bromine and magnesium
6 marks on practical
find average titre value and use this to find moles of MHCO3 reacted- 0.102 conc of hcl 250cm3 in 25cm3 amounts. something .7 and the moles are 0.041
rmm is 149

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Chloride ions oxidation
2Cl- -> Cl2 + 2e-


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Reply 2
anyone know about the 6 marker?
Original post by nadeu01
anyone know about the 6 marker?


The volumetric solution one?

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Reply 4
Original post by DaVinciGirl
Chloride ions oxidation
2Cl- -> Cl2 + 2e-


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ah **** i didnt balance
Reply 5
Original post by DaVinciGirl
The volumetric solution one?

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yep
Reply 6
what did everyone think of the exam doe?:frown:
white precipitate was barium sulphate, percentage mass was 34. something, mass of ammonia was 0.697, volume in P was 340cm3
Reply 8
Original post by IntellectualBoss
Alright I've put together a couple questions I remember from the exam and the answers, put through your questions or answers you dont agree with!

1.) chromium ion, 1s2 2s2 2p6 3s2 3p6 3d3
2.)aluminium 1s2 2s2 2p6 3s2 3p1
which ion has the same structure as krypton with a 2+ charge- strontium
which compound has a ion with 2+ from argon and 3- from argon- Ca3P2
bromine mass spectrum- 50% at 158 and 50% at 162
5 marks on bromine and magnesium
6 marks on practical
find average titre value and use this to find moles of MHCO3 reacted- 0.102 conc of hcl 250cm3 in 25cm3 amounts. something .7 and the moles are 0.041
rmm is 149


What did you get for the MPC on equlibria?
Reply 9
Original post by IntellectualBoss
Alright I've put together a couple questions I remember from the exam and the answers, put through your questions or answers you dont agree with!

1.) chromium ion, 1s2 2s2 2p6 3s2 3p6 3d3
2.)aluminium 1s2 2s2 2p6 3s2 3p1
which ion has the same structure as krypton with a 2+ charge- strontium
which compound has a ion with 2+ from argon and 3- from argon- Ca3P2
bromine mass spectrum- 50% at 158 and 50% at 162
5 marks on bromine and magnesium
6 marks on practical
find average titre value and use this to find moles of MHCO3 reacted- 0.102 conc of hcl 250cm3 in 25cm3 amounts. something .7 and the moles are 0.041
rmm is 149


The first question is wrong. And so is the 3rd one. Surely the 4s subshells fills before the 3d one so its 4s1 3d2. Then the third one is Ca3P2. As you needed to get the ions and balance the charges.


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It was incredibly difficult and I got 93% in the specimen paper which everyone said was hard, I would expect grade boundaries to be around 70% for A.
Density of gold was 19.3

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Original post by Suffy
The first question is wrong. And so is the 3rd one. Surely the 4s subshells fills before the 3d one so its 4s1 3d2. Then the third one is Ca3P2. As you needed to get the ions and balance the charges.


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No in transition metals the 4s electrons are lost first then the d electrons
Original post by Suffy
The first question is wrong. And so is the 3rd one. Surely the 4s subshells fills before the 3d one so its 4s1 3d2. Then the third one is Ca3P2. As you needed to get the ions and balance the charges.


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Thats correct but when transition metals lose electrons they lose from their s shell first so its 3d3
I think this was a question
Mg2+ and Na+ which is has the smallest atomic radii?
I wrote Mg as it has same shielding, and number of electrons but has more protons. So more nuclear attraction between electron and nucleus.

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Original post by RoughER
What did you get for the MPC on equlibria?


exothermic and brown because pressure increase favours N202 and it made it paler so we can assume n202 is the colourless one and an increase in temperature made it darker so backward reaction is endothermic so forward is exothermic
Reply 16
Weren't the peaks at 158 and 162 ~75% and ~25%?
Which board and paper is this?
The equilibrium colour
NO2 was brown and forward reaction is exothermic

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Original post by Lemonpopsicle2
Which board and paper is this?


Aqa

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