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    (Original post by Anno007)
    H is not an R group. The 3.1-3.9 is for an ether group.
    R group can be hydrogen...Name:  image.png
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    why am I even on here when i have an F214 in a couple of days



    but seriously, screw chemistry. I'm just done with these silly questions, was hoping for nice buffer questions and a load of mechanisms but I get a 9 marker on NMR and 1 markers that took an average of 3 mins each to do
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    1st question Ph calc
    2nd question nucleophilic addition ethane12 diol
    3rd question Kc value 9.09x10-3 answer mol-1 dm6
    4th question electrophilic substitution
    5th amino acid hydrolyse medical stitches
    6 unsure
    7 rate iodine h+ graph tangent r=k(H+)
    8 8 marks for Naoh kcn hz Ni
    9 molecular formula proof using empirical formula and that 9 marker 12 marks here

    wat was question 6
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    O
    (Original post by Anno007)
    H is not an R group. The 3.1-3.9 is for an ether group.
    Plus what would the chemical shift of a CH2 next to an alcohol group be then?
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    CHEM5 is our only hope 😩


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    Attempting version 1 of the unoffical mark scheme, will keep quoting this for others to see, may even start a thread. Please contribute i will update frequently before i start studying for my bio exam day after tomorrow heh rip

    Equation representing ethanoic acid as a base with nitric acid:
    CH3COOH + HNO3 -> CH3CO+NO3- + H2O

    Advantage of using the polyester suture rather than the polyalkene?
    the ester bond in polyester can hydrolyse whereas polyalkene C-C, C-H bonds are too strong thus cannot. Therefore the former can dissolve naturally whereas the former would require manual removal.

    Identify what reagents are needed to distinguish between the two chlorine molecules, incl. observation. (Acyl chloride vs haloalkane (?))
    Reagent: water/AgNO3 (?)/named carbonate
    Observation: HCl fumes/White ppt./Effervescence -for the acyl chloride.

    Which Nitrogen acts as a stronger base a vs. b (where a is attached to the benzene, and b is a tertiary amine) and why?
    Nitrogen b due to the positive inductive effect of the carbons on the nitrogen, therefore making the lone pairs more available. Consequently nitrogen a is joined to a benzene so the lone pair delocalises into the benzene ring.

    Order of reactions:
    D 1 or 0 ??E 2

    Why is the initial rate of the reaction used to determine the order of the reactants rather than at any other point during the reaction? Or something
    Initial rate takes into account the initial concentration of the reactants which is more accurate since, as the reaction proceeds the concentrations of the different species change. (?)

    How do you calculate the initial rate of the reaction from a graph of concentration against time?
    Calculate the gradient of the tangent to the slope. (?)

    Organic synthesis to produce the branched primary amine:
    Structure: Same as previous however Br is substituted with CN
    Step 3: KCN w/ ethanol (?)
    Step 4: H2/Ni, LiAlH4

    What is a racemic mixture?
    Mixture containing equal quantities of each enantiomer.

    How to distinguish between the two:
    Expose to plane polarised light, rotates in opposite directions

    Chiral Carbon relationship:
    They are both mirror images of each other/enantiomers.

    Question 9 Notes (I don't even need to say the question, everyone knows this question by the number... eek)
    Potassium dichromate turns green, either a primary or secondary alcohol, or aldehyde
    O-H absorption in the Mass spec
    O-H in NMR spectrum, singlet obvs
    CH3-O present in NMR spectrum, singlet
    RCH2 in NMR spectrum, triplet ?
    R(CH3)2 in NMR spectrum, doublet ? uh pls halp don't remember values.
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    (Original post by Rob1245)
    hey guys, so it was definitely a worse paper than the past few years but do we have a estimation for grade boundaries? and would 70 realistically get a B? thanks and hope everyone does a bit better in chem 5
    I think it could be possible for 70 to be a B, as it was a hard paper and last year was 71
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    (Original post by FireBLue97)
    1st question Ph calc
    2nd question nucleophilic addition ethane12 diol
    3rd question Kc value 9.09x10-3 answer mol-1 dm6
    4th question electrophilic substitution
    5th amino acid hydrolyse medical stitches
    6 unsure
    7 rate iodine h+ graph tangent r=k(H+)
    8 8 marks for Naoh kcn hz Ni
    9 molecular formula proof using empirical formula and that 9 marker 12 marks here

    wat was question 6

    this helps, i'll remake it in this format, might remember a few
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    2015 it was 85 for an A* and 78 for an A.
    I'm certain this paper was much more difficult so I would imagine 83/ for an A* and 75 for an A. 120 ums being about 90 I reckon.
    Opinions on what you think?

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    (Original post by ahsan_ijaz)
    Dude 15/20 marks dropped is like a. a* which world are you in?


    Posted from TSR Mobile
    yeah there is 0 change i could get an A* or even an A. . A* might be too much, but 3 hours and i could getan A easy.
    This sounds stupid and arrogant i know ; Im not some really smart person, just average really; but i mean i was honestly really ready for this exam, i understood every topic really well, did all past papers, and some from my school. I could answer every one, all the equations were easy, and what i found hard was the N.M.R questions where you have to draw the molecule, but i revise for it a lot, did every single past paper Q and after doing 2 , it clicked and i could do it . I honestly cant stress how ready i was for this exam, i knew how everything was made, the condition, reagents, I knew all the Buffer,Acid,Equal, question by heart, i havent failed a single one of those Q's. The kinetic my good, thats easy. In the exam it took me no time to do it . I honestly pissed, since this is the first time in my life, i went full on revision on an exam and was really ready for it, but i just flopped it so bad .. last year with last min revision i did better . I really wanted a A/ B min , and i put all the effort into it. Revised well before the exam, did every past paper, incase there a few werid Q's, did all teh work my teacher gave and got as much help as he would offer ..... I was ready for this and when i saw the exam, it looked easy enough, though some easy Q's from past paper werent there, E.G: water PH , Buffers .. where the **** were the 2 4/5 mark buffer Q's ? .. even then i wasn't really having any difficulty with the exam .. i just ran out of time, which is 100% my fault .. but this is the first exam ive done, where i ran out of time, usually i finish 10 mins early or more.
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    (Original post by bluhbluhbuh)
    Attempting version 1 of the unoffical mark scheme, will keep quoting this for others to see, may even start a thread. Please contribute i will update frequently before i start studying for my bio exam day after tomorrow heh rip

    Equation representing ethanoic acid as a base with nitric acid:
    CH3COOH + HNO3 -> CH3CO+NO3- + H2O

    Advantage of using the polyester suture rather than the polyalkene?
    the ester bond in polyester can hydrolyse whereas polyalkene C-C, C-H bonds are too strong thus cannot. Therefore the former can dissolve naturally whereas the former would require manual removal.

    Identify what reagents are needed to distinguish between the two chlorine molecules, incl. observation. (Acyl chloride vs haloalkane (?))
    Reagent: water/AgNO3 (?)/named carbonate
    Observation: HCl fumes/White ppt./Effervescence -for the acyl chloride.

    Which Nitrogen acts as a stronger base a vs. b (where a is attached to the benzene, and b is a tertiary amine) and why?
    Nitrogen b due to the positive inductive effect of the carbons on the nitrogen, therefore making the lone pairs more available. Consequently nitrogen a is joined to a benzene so the lone pair delocalises into the benzene ring.

    Order of reactions:
    D 1 or 0 ??E 2

    Why is the initial rate of the reaction used to determine the order of the reactants rather than at any other point during the reaction? Or something
    Initial rate takes into account the initial concentration of the reactants which is more accurate since, as the reaction proceeds the concentrations of the different species change. (?)

    How do you calculate the initial rate of the reaction from a graph of concentration against time?
    Calculate the gradient of the tangent to the slope. (?)

    Organic synthesis to produce the branched primary amine:
    Structure: Same as previous however Br is substituted with CN
    Step 3: KCN w/ ethanol (?)
    Step 4: H2/Ni, LiAlH4

    What is a racemic mixture?
    Mixture containing equal quantities of each enantiomer.

    How to distinguish between the two:
    Expose to plane polarised light, rotates in opposite directions

    Chiral Carbon relationship:
    They are both mirror images of each other/enantiomers.

    Question 9 Notes (I don't even need to say the question, everyone knows this question by the number... eek)
    Potassium dichromate turns green, either a primary or secondary alcohol, or aldehyde
    O-H absorption in the Mass spec
    O-H in NMR spectrum, singlet obvs
    CH3-O present in NMR spectrum, singlet
    RCH2 in NMR spectrum, triplet ?
    R(CH3)2 in NMR spectrum, doublet ? uh pls halp don't remember values.

    did it ask how to distinguish between the two?
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    (Original post by FormlessBowl)
    It wasnt quite the same question though



    the OCR question specified 2 products, the AQA one didn't - I think the answer I gave is likely to be accepted but the one above will be the first answer
    You might be right then
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    (Original post by bluhbluhbuh)
    Attempting version 1 of the unoffical mark scheme, will keep quoting this for others to see, may even start a thread. Please contribute i will update frequently before i start studying for my bio exam day after tomorrow heh rip

    Equation representing ethanoic acid as a base with nitric acid:
    CH3COOH + HNO3 -> CH3CO+NO3- + H2O

    Advantage of using the polyester suture rather than the polyalkene?
    the ester bond in polyester can hydrolyse whereas polyalkene C-C, C-H bonds are too strong thus cannot. Therefore the former can dissolve naturally whereas the former would require manual removal.

    Identify what reagents are needed to distinguish between the two chlorine molecules, incl. observation. (Acyl chloride vs haloalkane (?))
    Reagent: water/AgNO3 (?)/named carbonate
    Observation: HCl fumes/White ppt./Effervescence -for the acyl chloride.

    Which Nitrogen acts as a stronger base a vs. b (where a is attached to the benzene, and b is a tertiary amine) and why?
    Nitrogen b due to the positive inductive effect of the carbons on the nitrogen, therefore making the lone pairs more available. Consequently nitrogen a is joined to a benzene so the lone pair delocalises into the benzene ring.

    Order of reactions:
    D 1 or 0 ??E 2

    Why is the initial rate of the reaction used to determine the order of the reactants rather than at any other point during the reaction? Or something
    Initial rate takes into account the initial concentration of the reactants which is more accurate since, as the reaction proceeds the concentrations of the different species change. (?)

    How do you calculate the initial rate of the reaction from a graph of concentration against time?
    Calculate the gradient of the tangent to the slope. (?)

    Organic synthesis to produce the branched primary amine:
    Structure: Same as previous however Br is substituted with CN
    Step 3: KCN w/ ethanol (?)
    Step 4: H2/Ni, LiAlH4

    What is a racemic mixture?
    Mixture containing equal quantities of each enantiomer.

    How to distinguish between the two:
    Expose to plane polarised light, rotates in opposite directions

    Chiral Carbon relationship:
    They are both mirror images of each other/enantiomers.

    Question 9 Notes (I don't even need to say the question, everyone knows this question by the number... eek)
    Potassium dichromate turns green, either a primary or secondary alcohol, or aldehyde
    O-H absorption in the Mass spec
    O-H in NMR spectrum, singlet obvs
    CH3-O present in NMR spectrum, singlet
    RCH2 in NMR spectrum, triplet ?
    R(CH3)2 in NMR spectrum, doublet ? uh pls halp don't remember values.
    order of D was 1
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    I wrote that that propanone would be considered a constant when the concentration is 100x more than iodine and Hcl, don't know what i was thinking
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    (Original post by Weeksy97)
    I think it could be possible for 70 to be a B, as it was a hard paper and last year was 71
    ok thank you! going through my paper near the end i was had done a lot worse than i first thought fingers crossed!!
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    (Original post by emma_1111)
    did it ask how to distinguish between the two?
    idk my brain is mush, did it? xD
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    (Original post by emma_1111)
    did it ask how to distinguish between the two?
    naa

    the question was 'what is the relationship between the two chiral compounds'
    ANSWER: They are non super imposable mirror images of each other
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    (Original post by bluhbluhbuh)
    acid base reaction with ethanoic acid and nitric acid?

    i got tertiary, crossed it out, then did whatever heh, hopefully i get working out marks.
    And **** my life i wrote NH3 ine xcess, completely forgot cyanide was added prior to it... **** **** ****
    your not the only one but I swear the final product had an extra CH2 below the CN?! or am I just imagining this
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    For Q8 I put H2 and a nickel catalyst for the reduction of the nitrile, would this be accepted?
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    I mistook the acyl chloride/haloalkane for aldehyde and ketone 😭😭😭 so I put tollens
 
 
 
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