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    Can someone explain this question and answer to me? its about enthalpy and calorimetry. "Give reason, other than hear loss, why the value obtained from student's results are less exothermic than a data book value?" The answer is incomplete combustion but why?
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    Less energy is released when co or c are made instead of co2 (aka incomplete combustion) so if less energy is released this will make the enthalpy value less exo
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    (Original post by black321)
    Less energy is released when co or c are made instead of co2 (aka incomplete combustion) so if less energy is released this will make the enthalpy value less exo
    (Original post by logicmaryam)
    Can someone explain this question and answer to me? its about enthalpy and calorimetry. "Give reason, other than hear loss, why the value obtained from student's results are less exothermic than a data book value?" The answer is incomplete combustion but why?
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    (Original post by logicmaryam)
    Can someone explain this question and answer to me? its about enthalpy and calorimetry. "Give reason, other than hear loss, why the value obtained from student's results are less exothermic than a data book value?" The answer is incomplete combustion but why?
    Hi

    Incomplete combustion will lead to soot, carbon monoxide and water.
    It is less exothermic than complete combustion, due to less heat energy being emitted.
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    (Original post by logicmaryam)
    Can someone explain this question and answer to me? its about enthalpy and calorimetry. "Give reason, other than hear loss, why the value obtained from student's results are less exothermic than a data book value?" The answer is incomplete combustion but why?
    The values in the book are average/mean values. Whereas the values attained by the student are under specific conditions.
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    Could somebody tell me what it would mean if a cream precipitate forms, and then dissolves when nitric acid is added? I understand that nitric acid removes carbonate ions, but i was under the impression that carbonate ions form a white precipitate? Thanks!
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    When you heat under reflux is it a open or closed top?


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    (Original post by Supermanxxxxxx)
    When you heat under reflux is it a open or closed top?


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    Open

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    (Original post by jadys10)
    Anyone have any tips on good ways to revise chemistry? I'm really struggling. Plain reading the book isn't working and with making notes I tend to waste a lot of time getting it all neat and pretty and end up not getting much in my head, plus it's really quite late stage to be making notes now. I also didn't want to do papers till later because there aren't many so I want to save them. What do I do???
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    I actually haven't even learnt the majority of the content either :cry: I'm selfstudying it and left it soooo late I know
    It's ok, this is me in Chemistry and Physics...sigh. What I've learnt that's working for me is to use the specification as a checklist. Literally, it tells you things to expect- what definitions you need to learn as only certain things you will be asked on. On Physics maths tutor- he has a page with past papers listed by the contents which helped me as after going over a chapter of for example moles- I found past paper questions only on moles from 2009-2013. So you're still doing the past papers, only by content each. I literally have so much to learn and probably wouldn't finish everything due to Physics as Physics right now :'( it's sad. But if worst coms to worst- there are also notes you can use on Physics maths tutor for Chemistry or anywhere. Then watch videos to understand the content. This seems to be going ok so far for me but everything at the moment is taking too much time lol. Don't worry, I'm sure I'm in a worse position that you x
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    (Original post by jadys10)
    Anyone have any tips on good ways to revise chemistry? I'm really struggling. Plain reading the book isn't working and with making notes I tend to waste a lot of time getting it all neat and pretty and end up not getting much in my head, plus it's really quite late stage to be making notes now. I also didn't want to do papers till later because there aren't many so I want to save them. What do I do???
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    I actually haven't even learnt the majority of the content either :cry: I'm selfstudying it and left it soooo late I know
    Type/write notes in your own words. Then do every single past paper.

    Make a Microsoft Excel document with all of your exam marks, and have a column for each chapter, where you can add notes for things you do not understand. It really helps.

    Like this:

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    (Original post by johnnypong)
    You can use the papers from the old A level to revise too. Most of the syllabus is the same...just a few tweaks that you can ignore (eg Friedel-Crafts methylation of a benzene ring). The papers are arranged differently, but the questions are very similar.

    try this site...

    http://pastpapers.org/chemistry-as-papers
    Thanks for the link
    But honestly, if someone purely used past papers without learning or reading the content from the book- what grade could they receive as these questions seem almost recycled. Say if I did 20 past papers- could I get maybe grade B through only doing that and looking at mark schemes?
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    (Original post by TARS)
    Type/write notes in your own words. Then do every single past paper.

    Make a Microsoft Excel document with all of your exam marks, and have a column for each chapter, where you can add notes for things you do not understand. It really helps.

    Like this:

    Oh my gosh, you're very creative! I may sound naïve but how do you think of these things? You all seem so dedicated and prepared- I don't even have time to do this because I somehow entered a sad position. But I've started studying and 'learning' the content now.
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    (Original post by Cherry82)
    Oh my gosh, you're very creative! I may sound naïve but how do you think of these things? You all seem so dedicated and prepared- I don't even have time to do this because I somehow entered a sad position. But I've started studying and 'learning' the content now.
    It was my physics teacher's idea really, but I just did it and tried it out and it seemed to work so i continued it for all past papers
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    (Original post by Cherry82)
    Thanks for the link
    But honestly, if someone purely used past papers without learning or reading the content from the book- what grade could they receive as these questions seem almost recycled. Say if I did 20 past papers- could I get maybe grade B through only doing that and looking at mark schemes?
    there's nothing stopping you get 75+ doing that, i'd say there's 5 marks max of new stuff per paper
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    (Original post by BBeyond)
    there's nothing stopping you get 75+ doing that, i'd say there's 5 marks max of new stuff per paper
    Isn't the paper out of 60 though, or is this in the sense of UMS points or something? But really, this sounds too simple though. If it was that easy why isn't everyone doing this? lol- this would be very risky for someone like me who wasn't gone through the whole book and who doesn't know the pieces of the content...
    I don't know why but I really hate that official study guide ocr set students. Actually I think it's due to the fact that it doesn't really point out things, there's just large pieces of content without highlighted, underlined info. I had to buy another study guide.
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    (Original post by Cherry82)
    Isn't the paper out of 60 though, or is this in the sense of UMS points or something? But really, this sounds too simple though. If it was that easy why isn't everyone doing this? lol- this would be very risky for someone like me who wasn't gone through the whole book and who doesn't know the pieces of the content...
    I don't know why but I really hate that official study guide ocr set students. Actually I think it's due to the fact that it doesn't really point out things, there's just large pieces of content without highlighted, underlined info. I had to buy another study guide.
    Because you still have to learn the answers and its much harder to learn the answers when you don't even understand the concept hence why past papers are usually the kinda thing an A grade student does for full ums rather than a D grade student for a B.also most don't use them correctly and it can be quite time consuming.

    For my biology mock I did 1 past paper for practice and it helped for around 20 marks/80, plus 1 of the questions was a exact copy.


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    (Original post by lyricalvibe)
    Because you still have to learn the answers and its much harder to learn the answers when you don't even understand the concept hence why past papers are usually the kinda thing an A grade student does for full ums rather than a D grade student for a B.also most don't use them correctly and it can be quite time consuming.

    For my biology mock I did 1 past paper for practice and it helped for around 20 marks/80, plus 1 of the questions was a exact copy.


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    Wait, so sorry no offence but what's the point you're making? That past papers do or do not help depending on?
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    (Original post by Cherry82)
    Wait, so sorry no offence but what's the point you're making? That past papers do or do not help depending on?
    Oh sorry, I was replying to the, "if its that easy why doesn't everyone do it"
    I personally find them really useful, but I only like using them in conjunction with revision guides.

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    (Original post by lyricalvibe)
    Oh sorry, I was replying to the, "if its that easy why doesn't everyone do it"
    I personally find them really useful, but I only like using them as a supplement to revision guides.

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    Oh, I understand now. There's been previous articles though on OCR doing this- using old past paper questions like from 2004 in recent papers. I remember reading an article or something- this was like in 2012. How students who did the 2002 past paper got 10 marks free for their A2 exam. Now that it's been raised, I'm sure OCR wouldn't do this again but those students were lucky.
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    (Original post by Cherry82)
    Oh, I understand now. There's been previous articles though on OCR doing this- using old past paper questions like from 2004 in recent papers. I remember reading an article or something- this was like in 2012. How students who did the 2002 past paper got 10 marks free for their A2 exam. Now that it's been raised, I'm sure OCR wouldn't do this again but those students were lucky.
    Are you OCR B? My teachers said its quite likely this'll happen as its the last year for the spec, are you planning on looking at old spec stuff?

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