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T Totals Coursework Mark Scheme Chemistry

12/3/18 Update: I, as per forum rules, will not be distributing the papers I acquired after my exams. However, if people sat them for a mock or otherwise attained them, and would like some worked examples I'd be more than happy to help if you send me a PM, granted I can find the papers when i return home from Uni at the end of this term (27/3/18).

I've had a second look at the paper. here's a few of my answers (not in order):

AlH4: 3 covalent bonds and one dative bond
NH4+ - Tetrahedral, 109.5
NH2- - non-linear, 104.5
NH3>PH3 because H bonds. AsH3>PH3 as more E's so more dipole-dipole interactions so stronger London forces.
Group 2 metals increase in reactivity as shielding increases, atomic radius increases, nuclear charge increase outweighed by inc. in radius and shielding so outer electrons less attracted by nucleus so easier to remove hence more reactive.

Ba(NO3)2(aq) + Na2SO4(aq) -> BaSO4(s) + 2NaNO3(aq) | Entropy decreases as solid formed which is more ordered
1/2 I2(s) -> I(g) | Entropy increases as gas formed which is less ordered/more disordered
Acid/base pairs: CH3COOH(B2) + H2FCCOOH(A1) -> H2FCCOO-(B1) + CH3COOH2+(A2)
Kp = p(CO)^4
Kc = [SO3]^2/([SO2]^2[O2]) dm^3mol^-1, 2.45 mol so3

pH = 4.50002 (this is right, 4.86 IS wrong.) pH is constant on dilution as [H+] = Ka ([HA]/[A-]) and conc's cancel out the volume.
-110.5Kj/mol for Hf of CO
690cm^3
first order, rate at t=0: 1.84*10^-3, k=7.7-8*10^-4 units: s^-1 or per second (range of answers as from graph) halflife was about 900ish. graph had weird jumps so ppl might have messed up.
962 Kelvin, 467KJ for at 25 degrees which > 0 hence not feasible.
Disproportionation is when one species is both oxidised and reduced: Cl reduced from +5 to -1. Cl oxidised from +5 to +7.
Potassium Chlorate(VII) [maybe they'll give potassium perchlorate but that isn't the systematic name afaik.]
[Cu(H2O)6]2+ : with HCl = [CuCl4]2-, with dropwise NH3 = Cu(oh)2 with excess NH3 = [Cu(NH3)4(H2O)]2+ and with KI was I2(brown solution) and CuI(white ppt)
named reactions for above: Ligand substitution and Redox.
Free Energy question: y = mx + c : G = -S(T) + H, explain grad = -S, y int is c = H
Le chatelier's principle: Forward reaction was endothermic so high temperature favors it, forward reaction was going to more moles of gas so a low pressure favors forward reaction. Actual conditions may vary as cost of maintaining high temperature and low pressure is high so a catalyst is used in favor of 'ideal' conditions.
0.753 for something.
Zn was best reducing agent, MnO4- was best oxidising

https://gyazo.com/b77d7fda10b60699b9873d28a6417ff8
All solutions 1mol/dm^3, 298K



last question: DISCLAIMER: 'en' is NH2CH2CH2NH2 just wrote en for speed
A = [Ni(en)3]cl2*2H2O
B = [Ni(en)3]cl2
C = [Ni(en)3]2+ - correct optical isomers drawn
D = en = H2NCH2CH2NH2

if you can remind me of any questions I might remember my answer. I know what I put for Multiple choice but not what letter they were.
PS: these are not canon - they are MY answers.

MY grade boundary predictions:
89 - A*
80 - A
72 - B
64 - C
56 - E


Topics to revise for paper 3:
Born Haber
Titration with I2/(S2O3)2- and MnO4-
Arrhenius Equation/temperature effect on Kc
Cation and Anion tests (Cr3+, Fe2+, Fe3+, Cu2+, Mn2+, NH4+ | CO32-, SO4^2-, Cl-, Br-. I-, order for anions is important!
Relative reactivity of Halogens (Cl>Br>I)
Enthalpy
Boltzmann
Calculating Kp from initial amounts + kp units

Беккер молча ждал выстрела, который должен оборвать его жизнь. ГЛАВА 89 Лучи утреннего солнца едва успели коснуться крыш Севильи и лабиринта узких улочек под. Колокола на башне Гиральда созывали людей на утреннюю мессу.

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