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OCR Chemistry A Exam Thread (Breadth - May 27 2016 and Depth - June 10 2016) Watch

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    (Original post by jasonrose98)
    Someone may have mentioned this before, but for the electrontic config was it an Mg atom or ion? I was like 99% sure it was atom but loads of people from my college said they changed it to ion at the last minute
    It was deffo atom! I checked
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    Guys, did you draw the activation energy?
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    (Original post by asinghj)
    Guys, did you draw the activation energy?
    No, I think it said you did not have to. Did you put in delta H and the axes labels (or were these given?)
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    ****. I got 68.9% for the percentage yield...

    Will I get full marks or lose a mark or two?
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    for the enthalpy profile diagram. did u put N2 (g) and O2(g) as the reactants and N2O2 (g) as product.
    and +82kjmol-1 was the enthalpy change right
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    for the difference between sigma and pi bond. I put sigma bond has a higher electron density than the pi bond. do u guys think i got a mark here
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    (Original post by 11...)
    it is methylpropanoic acid actually guys. it said that it was a secondary carbocation
    The answer is 2-methylpropanoic acid. Reasons being if you google 2-methylpropanoic acid mass spectrum and butanoic acid mass spectrum, you will see that the 2-methylpropanoic acid spectrum matches the one found in the paper
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    (Original post by 11...)
    for the difference between sigma and pi bond. I put sigma bond has a higher electron density than the pi bond. do u guys think i got a mark here
    Nah I think you have to talk about the sigma bond being spherical shaped and the pi bond being dumbbell shaped
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    (Original post by asinghj)
    Guys, did you draw the activation energy?
    I'm certain it said you do not need to draw activation energy on it.
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    I said sigma bond is made from overlap of s orbital.
    Pi bond is made from sideways overlap of P orbitals.
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    (Original post by Feisal_2374)
    Nah I think you have to talk about the sigma bond being spherical shaped and the pi bond being dumbbell shaped
    the s orbital is spherical and the p orbital is dumbbell shaped not the bonds
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    (Original post by 11...)
    the s orbital is spherical and the p orbital is dumbbell shaped not the bonds
    Damn lol messed up
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    what mark do you guys think you got??? by the way where is the unofficial mark scheme. pls tell me the link for it if there is one
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    Hoping for 100/140 for a B
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    what do you think an A would be out of 140. hope it is 110/140
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    For the last question I reached the correct answer and clearly drew out the structure of Compound C and everything. Got fragment ions and everything.
    Only thing is, I didn't name it. Will I lose marks?
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    nobody did an unofficial mark scheme
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    I think I got 61/70 on that paper.
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    (Original post by Kienzan)
    For the last question I reached the correct answer and clearly drew out the structure of Compound C and everything. Got fragment ions and everything.
    Only thing is, I didn't name it. Will I lose marks?
    I don't think so. It just said identify compound C not name it. so I think you will get all the marks, unless ocr decides to be so specific
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    (Original post by Questioness)
    I'm certain it said you do not need to draw activation energy on it.
    It said something along the lines of you are not expected to know the activation energy, so I did the curve from reactants to products and labeled Ea but put no value
 
 
 
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