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Homework Help: Marked Unfairly

  1. Dec 6, 2008 #1
    I'm started college in September and I have a bit of a headstart since I've already studied chemistry and I noticed the teacher was teaching some inaccuracies to the class (for the sake of simplicity?) and I wasn't trying to undermine him or anything but I cleared it up and said how it really was. Mistake on my part though because he has a bit of a grudge against me now and shows me no mercy. No matter how hard I try I can't seem to get full marks on any assignments and we did a practice test which was on stuff I already know but I only got 52%. Can anyone tell me if my answers are just badly explained or if he's marking unfairly. I'll give a few examples

    Q1.) What is meant by a mole of a substance?
    A.) A mole is a set quantity of atoms of a particular substance.
    I think I explained that badly I picture a mole as avagadro's number of atoms of an element or molecules of a compound. His definition is "formula mass in grams". To me thats an incomplete definition at best.

    Q7.) I was asked to write the electron configuration (s,p,d) of a few elements such as calcium and I accidentally wrote the wrong way around and he gave me no marks at all. Instead of writing 1S2 I wrote 2S1. I wrote the full electron configuration though so any chemistry teacher could see the answer was right it was just the layout I messed up.

    Q8.) I was asked to describe the various types of chemical bonds. I lost loads of marks on this one
    Van der Waals Bond - Weak bond caused by intermolecular forces of polar molecules (Got no marks for that one)

    They're the only ones that he gave me absolutely no marks for but a lot of the other ones he gave me 1 or 2 marks. The overall result was 52%. I'm gonna have to really study hard if I'm gonna have a chance of passing the real exam.
  2. jcsd
  3. Dec 6, 2008 #2
    Happens to me all the time, just hate those kind of teachers. You just have to suck it up, and hope you write what he wants next time. Does this guy give notes, and how is his attitude when you approach him?
  4. Dec 6, 2008 #3


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    I don't know about the definition questions, but #7. is wrong, plain and simple. I'm not sure how you can expect any marks for a wrong answer. :confused:
  5. Dec 6, 2008 #4
    No he doesn't give any notes which makes it 10 times harder to know how he wants the concepts to be described. He only gives question sheets which are all about calculating quantities. I like those kinda questions though cuz theres only 1 definite answer to them I can't go wrong.

    His attitudes defensive. When I'm only asking questions he thinks I'm trying to catch him out on something. Sometimes when he finishes explains something to the class he asks me "Is that alright?" as a joke. Its one of those first impression things. He thinks I'm one of those arrogant pricks that thinks he knows more than the teacher but thats not the case at all I was just trying to help paint an accurate picture of the concepts he was explaining.

    I thought he was cool from the start I liked him so thats the only reason I was so up front with him I didn't think he'd develop a grudge against me. I learned my lesson but I have to live with the consequences for the rest of the year because he's the one marking my assignments. The exams there'll be an external examiner so he can't mark unfairly but these assignments make up a lot of the overall marks.

    I suppose I just have to use his own definitions word for word.
  6. Dec 6, 2008 #5
    Thats exactly what he said about #7 too cristo. I thought they disregarded spelling and format mistakes. Ah well I'll get it right next time. The good thing is this practice test covers most of whats gonna be on the real exam so he says. Now I know where I would have gone wrong so I won't make the same mistakes on the real thing.

    Its just the explaining thing I know the concepts in my head but my descriptions don't always paint an accurate picture.
  7. Dec 6, 2008 #6


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    You weren't wrong but the definition you gave isn't pratical... unless you want to start counting molecules or atoms. I'd give partial credit but not full credit.

    Yeah, that's just wrong. Take your time!

    Were you taught about Van der Waals Bonds? No such thing. Stick to covalent, ionic, hydrogen and metallic.

    It's probably best that you had a chance to practice since now you know what to expect. What you think you know is often more dangerous to your grade than what you don't know. You study what you don't know well and spend time on those answers while you ignore what you think you know and breeze through the answers without a second thought.
  8. Dec 6, 2008 #7


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    Sure, spelling mistakes and other errors shouldn't be overly penalised when it's an obvious mistake, but if you write something that makes sense, but is incorrect, then there's no way to give you the benefit of the doubt, and I don't teachers should do!
  9. Dec 6, 2008 #8
    I don't remember his definition for this van der waals bond but I don't get why he didn't accept mine.

    Also can someone explain to me what a covalent crystal is?
  10. Dec 6, 2008 #9
  11. Dec 6, 2008 #10
    Your papers were marked correctly, or at least all three of your answers were not *entirely* correct and there was room for your instructor to justify taking off points on each one:

    1. A mole is 6.022x10^23 of anything. I can have a mole of oranges if I had 6.022x10^23 oranges. Your answer wasn't wrong, but it was simultaneously too broad of a definition (did not mention the actual quantity of 6.022x10^23) and too narrow of a definition (you can have a mole of many things in science other than atoms, for example "a mole of photons").
    2. 1S^2 is not the same thing at all as 2S^1.
    3. Van Der Walls/London Forces are weak interactions that can take place between polar and NON-polar substances. They are so weak that they are insignificant compared to other interactions in polar molecules such as ionic interactions (and as someone mentioned before these are not considered bonds in a strict sense).

    The question of fairness arises by how *other* students papers were marked in comparison to yours. If they made the same mistakes and received more partial credit than you did, then the standard is being applied unfairly and you have a right to complain (although I caution you to consult your parents or some other adult about the potential consequences before doing so...). Otherwise, this might just be the way he grades.

    I have had teachers target me and try to downgrade me (not because I spoke up in class, but because I was an overachieving nerd on paper and some instructors were resentful of that). When dealing with these types you just have to study your butt off and give them NO room at all to mark your answers wrong (i.e. you have to be in exact word perfect agreement with the textbook). That is your only defense.

    Also a general rule of thumb to consider: the more "loose and inaccurate" a person tends to be on a day to day basis the more likely they will attack you or anyone else that attempts to correct them. Think about it, if they were more open to others correcting them, they wouldn't end up becoming as inaccurate as they are. Please keep this in mind.
  12. Dec 7, 2008 #11
    If by Van der Waal's bond you mean dispersion forces, it occurs when one atom has a temporary dipole, which then induces other temporary dipoles on surrounding atoms, and it causes a weak interaction between (temporarily) separately charged atoms.
  13. Dec 7, 2008 #12


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    Neither of the definitions listed for mole is fully correct.


    But if anything, I would first dismiss "formula mass in grams" as incorrect, as it concentrates on the secondary property (mass) and not on the primary property (number of entities). Note that molar masses of some elements depend on their source (I believe for boron difference is in the range of +/- 0.01), thus mole of boron from different sources has different mass (but identical number of atoms). MadmanMurray answer is better, not sure if it deserves full credit.
  14. Dec 7, 2008 #13
    Yeah thats what I was trying to get at Borek. I visualize a mole as a quantity of something not how much something weighs. A mole of sodium has the same amount of atoms as a mole of rhodium but theres a huge weight difference between a mole of those 2 elements. Like I said I have the concepts in my head I just have trouble explaining them.

    This isn't a high school course its a further education course to prepare you for university. When I see the teacher giving definitions that paint an inaccurate picture it makes me wonder how much inaccuracies I won't be able to spot down the line. I see where he's coming from with his "formula mass in grams" but thats a way more complicated explanation and its not even accurate. Why not just explain that a mole is a quantity (avagadro's number) of something.

    I learned my lesson though its best to keep your mouth shut. He's the teacher not me. The other teachers like it when I shout out an alternative explanation for a concept they're trying to explain because it makes their job easier though. For instance the physics teacher was having trouble getting people to understand what displacement and I noticed he was trying to explain it in a purely verbal way so I took the visual approach and told him to draw 2 points on the board. As simple as that. Its easier to learn when you can visualize a concept.
    Last edited: Dec 7, 2008
  15. Dec 7, 2008 #14


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    While that's very close, and for all practical prurposes difference can be neglected, mole is NOT defined through the Avogadro's number.
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