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Chemistry edexcel 12 June paper 2

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10
Q1 free radical substitution, carbon, 2-methylpropan-1-ol, reforming

Q2 absorbed
Gaseous products are absorbed into honeycomb and collide more due to compact honeycomb, so more successful collisions that result in reaction
2NO + 2CO - - 2CO2 + N2

Q3 ninhydrin
Rf = 0.167 (3sf)
One amino not present, as all the other Rf values are too far away from the tripeptide (only two are relatively close) so other amino must be something not included in samples.

Q4 83 point something grams of NaN3 (using ideal gas equation)

SiO2 used, as it reacts with metal oxides to get rid of reactive metal oxides, and lower total gas volume so airbag can deflate?

Peak down and to the left


Q5 Haloalkane experiment:

-nucleophillic substitution with aqueous silver nitrate
-react haloalkane with aq, solid silver halide precipitate formed as well as alcohol.
-colour of precipitate indicated type of halide ion
-after fixed time, remove any precipitate by filtration
-recrystallisation for solid precipitate to purify, then weigh.
-higher rate = faster rate of hydrolysis

Iodo is most reactive as I is the largest atomic radius, C-I is weaker, heterolytic fission occurs more rapidly

6 marker:

-primary has negative transition state
-SN2 nucleophilic substitution
-two substances in rate determining step
-partial order of haloalkane and OH- is 1
-primary alcohol formes

-tertiary has positive carbocation
-SN1 nucleophillic substitution
-carbocation more stable due to hyperconjugation
-SN1 is quicker (carbocation is lower energy level)
-tertiary alcohol

Q6 and 7

Synthesis is benzene + ethanoyl chloride - - A, then reduce with LiAlH4 in dry ether - - B,
Then elimination with phosphiric acid - - final product

Phenol with bromine, drew free radical addition, but is it E substitution? Or could it be either?

Either way, lone pair on oxygen drawn into ring, more electron density than benzene, stronger nucleophile so faster

NO2 e substitution mechanism, for isomer just moved the OH and NO2 one position clockwise.

Can't remember 8

Last question (9)

Iodate is first order
Starch to show colour change and show when all I- has turned into I2

Rate constant was 393 something units are mol-1dm3 s-1

Messed up the rest of this question tbh

Quite tough, slightly harder than 1 imo
(edited 5 years ago)

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