I thought it was an easy paper compared to the old spec, but cause it's a new spec might be slightly lower than usual, so probably similar to previous years imo
I thought it was an easy paper compared to the old spec, but cause it's a new spec might be slightly lower than usual, so probably similar to previous years imo
For the non polar molecule question I put E-2,3-dichlorobut-2-ene as this was the only molecule where the resultant dipole was right in the middle of the molecule
Hard to tell, totally depends on what the mark scheme says, it could say either
How many marks was the copper coin one i put it to 4 sig figs... did you have to write the x10^22 bit or did it already have it there and you just put the 3.whatever in?
Here's my attempt at an unofficial mark scheme, it is for the OCR Chemistry A, new spec, breadth in chemistry paper, really can only put the maths questions down, but if there are written ones I can remember I will put them down. This is only really for comparison of numbers, and general ideas
Multiple choice: BCDACBBDCBCBBCBDDBBD (if anyone happened to store their multiple choice answers on there calculator, please post them below to compare)
Same number of protons and electrons, different number of neutrons
Relative atomic mass: 63.62 No of atoms in 5.00g coin: 3.98 x 10^22 (3sf) Percentage error of water removed mass: 1.72% Volume of H2SO4 required to neutralise NaOH: 24.3cm^3 Enthalpy change of reaction: -58.5 kJmol^-1 Concentration of KI required: 3.3 moldm^-3 Concentration in equilibrium question: 0.876 moldm^-3
Homologous series: alkenes General formula: CnH2n
Electron configuration of bromide ion: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6
Equilibrium question: The equilibrium position will shift to the right, as the forward reaction is exothermic, in an attempt to reduce the effect of the temperature decrease. The equilibrium position will also shift to the right as there are fewer gas molecules in the products of the forward reaction, in an attempt to reduce the effect of the pressure increase. This may vary to the actual conditions as low temperature reduces rate of reaction, and it's expensive to have a high pressure.
Ways to reduce percentage uncertainty: use a larger mass of crystals to get larger mass of water removed, reducing % error
Last question: step 1 reagent, Br2, step 2 reagent, NaOH
If anyone remembers the written answers, please post and I'll add them, Any incorrect (although I don't think there are) please tell and I'll correct
Also, post about how you found the exam, as this will give a good idication of grade boundaries
You cannot use Br2 because you will make a dihaloalkane and you cannot make an alcohol from dihaloalkane. You had to use HBr to make haloalkane and then NaOH to make alcohol.
How many marks was the copper coin one i put it to 4 sig figs... did you have to write the x10^22 bit or did it already have it there and you just put the 3.whatever in?
No, you had to put the x 10^22, and also I don't think significant figures was specified in the question