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    (Original post by MMcG2015)
    I'm not sure, I wrote use a digital thermometer to take a more accurate reading, also to the other question about high pressure, it is correct for cracking.
    Few I knew pressure was the right one
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    (Original post by MMcG2015)
    I'm not sure, I wrote use a digital thermometer to take a more accurate reading, also to the other question about high pressure, it is correct for cracking.
    The answer is some sort of insulation or lid, to reduce heat loss. A similar question came up last year.
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    (Original post by 1jonam16)
    If you normally do it to 3 s.f. it's fine, but in this case the answer was perfectly 20.3. Therefore, they won't knock off a mark. There\s no need to worry for everything
    Exam tip 101- If the question uses 4 significant figures, YOU USE 4 SIGNIFICANT FIGURES otherwise you'll only get the mark for working out
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    (Original post by Teenw123)
    Exam tip 101- If the question uses 4 significant figures, YOU USE 4 SIGNIFICANT FIGURES otherwise you'll only get the mark for working out
    Dude it will not make any difference. Also, 20.30 is not to 4 significant figures, as a 0 in a decimal is not a significant figure (20.30 = 20.3)
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    (Original post by plex-)
    Dude it will not make any difference. Also, 20.30 is not to 4 significant figures, as a 0 in a decimal is not a significant figure (20.30 = 20.3)
    I've given up on life time to commit. You'll finally learn when you get marked down
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    (Original post by plex-)
    Dude it will not make any difference. Also, 20.30 is not to 4 significant figures, as a 0 in a decimal is not a significant figure (20.30 = 20.3)
    If the question said to give an answer to 4sf and you put 20.3 you will definitely be marked down but only 1 mark.
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    (Original post by plex-)
    Dude it will not make any difference. Also, 20.30 is not to 4 significant figures, as a 0 in a decimal is not a significant figure (20.30 = 20.3)
    Example- In one of my recent Physics mocks the answer to a question was 12. However I dropped a mark as I should have written 12.0 as the question used 3 significant figures
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    (Original post by Teenw123)
    Few I knew pressure was the right one
    I do an Access to Science course in chem and bio alongside my GCSE's (I'm 26 and had no qualifications, so basically had to start again for my uni course in September) and in one of my chem units we went right into cracking and it's definitely right to say pressure. High temperatures and pressures without a catalyst or lower temperatures and pressure with a catalyst.
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    There are 2 types of cracking, thermal and catalytic. One is high temp, high pressure. The other is still high temp (just not as high) and a catalyst (zeolite although others can probably be used). Either of the 2 should probably get full makes although to thermal cracking usually makes aliphatic/ and straight chain compounds (and alkenes).
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    (Original post by B_9710)
    If the question said to give an answer to 4sf and you put 20.3 you will definitely be marked down but only 1 mark.
    It didn't say that in the question though.
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    (Original post by plex-)
    It didn't say that in the question though.
    The other answers were to 4sf so your should have been to 4 as well
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    (Original post by Teenw123)
    The other answers were to 4sf so your should have been to 4 as well
    The question did not ask you to give your answer to 4 significant figures. M1 for workings (24.36 / 1.2) M2 for correct answer (20.3)
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    (Original post by plex-)
    The question did not ask you to give your answer to 4 significant figures. M1 for workings (24.36 / 1.2) M2 for correct answer (20.3)
    The calculation is there to trick you into believing that 20.3 alone was the right answer, on your own you're supposed to know that it's meant to be 4sf
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    (Original post by Teenw123)
    The calculation is there to trick you into believing that 20.3 alone was the right answer, on your own you're supposed to know that it's meant to be 4sf
    What did the question say? If it did not specifically state how many sf then how do you know it should be 4?
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    You will not get marked down because you did not do it to 4sf. There is nothing wrong with 20.3.. If it said give it to 4sf then that was the correct thing to do. However it didn't. 20.3 or 20.30, same thing, still will get the marks.
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    (Original post by Teenw123)
    The calculation is there to trick you into believing that 20.3 alone was the right answer, on your own you're supposed to know that it's meant to be 4sf
    Oh dear, this is chemistry not physics and more often than not, 3 s.f. is fine. You're making a fuss and gaining satisfaction from other people's supposed misfortunes for nothing. If we lose a mark, we lose a mark, though I doubt so.
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    That maths question was more P1 stuff lol and I put 20.3. Don' remember the question saying round to 4 sig. figures.

    RULE OF THUMB FOR EXAMS: Only answer what the question tells you. Even in maths they would tell you to round to a specific amount of sig. figures or decimal places. this is c1 and that wasn't in the syllabus so losing a mark for that would be a pisstake.
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    (Original post by 1jonam16)
    Oh dear, this is chemistry not physics and more often than not, 3 s.f. is fine. You're making a fuss and gaining satisfaction from other people's supposed misfortunes for nothing. If we lose a mark, we lose a mark, though I doubt so.
    Thank you!!!!!!! I HATE SHOW OFF'S DRIVE ME MAD LOL!!!!
 
 
 
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