All Leaving Cert Chemistry posts
  • avatar image

    Paper discussion ddp.cronin

    I personally thought that was the hardest Chem so far. Usually titration is simple and straight forward. Found this one hard. Anyone get 4.8% for w/v

    1. avatar image

      Chris241197

      yes whooooo got 4.8

    2. avatar image

      shannon8

      I got that too! I thought the paper was so hard, I was hoping for an A, got a B2 in the DEB, I'll be lucky to get that after that paper

    3. avatar image

      ddp.cronin

      What did you get for instanteneous rate at 4min

    4. avatar image

      MAYYAMIMI

      I got something like 7. .... I don't clearly remember but it was in the sevens

    5. avatar image

      Bengee

      What did you get for the Kc?

    6. avatar image

      Insa333

      Guys I got 48%. I reanalysed the paper and I don't think I'm wrong because they mentioned ORIIGINAL vinegar as opposed to DILUTED vinegar!!

    7. avatar image

      Chris241197

      pretty sure you'd be dead with 48% v/w in vinegar :) , but maybe you are right time will tell

    8. avatar image

      shannon8

      I think 8.something for the instantaneous rate. I think they asked for the diluted vinegar no?

    9. avatar image

      Chris241197

      no its original

    10. avatar image

      Bengee

      Googled it ... "optimum amount of acetic acid in vinegar is between 4 and 5 percent by weight." 4.8% sounds right

    11. avatar image

      ddp.cronin

      its 4.8%. Its 48% in the orginal but thats per L. You have to write it per 100cm

    12. avatar image

      1282

      4.8%

    13. avatar image

      conor6842

      w/v is per litre and i got 4.8% were we suppose to know the makeup of arsine?

    14. avatar image

      ddp.cronin

      it gave it in the question. As with 3 hydrogen atoms

    15. avatar image

      conor6842

      ahh fuck i couldent find it in the peroidic table too late now

    16. avatar image

      Longbottoms

      What did people get for the KC value in question 7?

    17. avatar image

      Aisling21

      For Kc I got 12.25 but think it's wrong.. I got loads of different answers and wasn't sure which to put down, went with this in the end

    18. avatar image

      Aisling21

      Which titrations are used to standardise sodium hydroxide?

    19. avatar image

      ddp.cronin

      I said anhydrous sodium carbonate to standardise HCl and then HCL to standardise sodium hydroxide ?

    20. avatar image

      Aisling21

      Ah yeah thanks that sounds right

    21. avatar image

      Fjfj

      I got something like 3920 for the Kc definitely wrong lol

    22. avatar image

      Longbottoms

      I got 196000

    23. avatar image

      Longbottoms

      for the KC

    24. avatar image

      what.the.matter.is.the

      KC was 196000

    25. avatar image

      what.the.matter.is.the

      I got like 7.5 or something in the instantaneous rate.

    26. avatar image

      what.the.matter.is.the

      I got around 7.5 in the instantaneous rate.

    27. avatar image

      Aisling21

      Agh I originally got that for Kc but thought it was wrong as there was a two at the start of the equation

    28. avatar image

      Sinott

      Different values of Kc probably came from whether moles were divided by the 50Litre volume of the container, which I believe was to be divided before subbing into the Kc expression.

    29. avatar image

      orlaithdd

      There was a misprint on the ordinary paper, HCL titration had the wrong chemical equation I think?

    30. avatar image

      laylalushni

      the kc i got had 4 numbers, but i converted the grams to moles, found the moles at equilibrium and divided by 50 then I used the formula to find the kc

    31. avatar image

      Insa333

      If 4.8% is the answer then I messed up in a place where I wrote 0.8 instead of 0.08. This meant my other answers further down were also affected by this. How many marks will I lose for this? Will I only be marked down for the initial slip or will marks be taken away from the other answers as well?

    32. avatar image

      michael.ryan.712714

      I am hoping that they will account for slips. They would hardly be that cruel

    33. avatar image

      michael.ryan.712714

      to take off marks for the remainder for the question

    34. avatar image

      momo5478

      Having done LC would you advise getting grinds if one only gets 74% in their summer house exam

    35. avatar image

      Insa333

      I am a firm believer, when it comes to subjects like chemistry and biology, that one will only waste money on grinds. Let alone the fact that I had great teachers in these subjects, I feel that the textbooks are so comprehensive and easy to follow. Working hard on each chapter and understanding the material is vital and this is made easy by the great layout of information in the textbooks.

    36. avatar image

      maria.pachowicz

      I got 4.8% for the concentration too, and 196,000 for Kc. My instantaneous rate was somewhere around 8 or 9 but they generally accept a range of values for that!

      Regarding grinds, I agree with Insa333 - I don't think any grinds teacher could explain the material better than the textbooks do! It takes time and work but it all clicks eventually

    37. avatar image

      Me

      Share files from your computer
      loader

Going to College