Sunday 11 September 2011

About the Mole.....



1.What are some of the other common misconceptions that you have encountered about the mole?
2. Are there some easier teaching strategies for this concept?

15 comments:

  1. This comment has been removed by the author.

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  2. Just checking to see if this message will be posted... Neelam

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  3. Hello Girls

    The activity you presented was very interesting.

    I remember when I was in my preliminary and HSC chemistry course I was left behind because I couldn't get my head around the concept of moles and using the multitude of equations that come alongside it.

    It wasnt until university that I began to understand this concept

    Perhaps this was due to the contrasting ways in which it was taught. During university chemistry the use of models and simulations was extensive. As this concept if very abstract, having models and analogues that immerse students into molecular relationships is much more successful than teaching from abstract numbers and equations.

    - Sarah Townsend :)

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  4. Question 1.
    Well, teachers talking about a "mole" the small animal when introducing the concept of moles, even to state "we aren't talking about the little furry animal". Is quite distracting and decreases my engagement, as i'd surely wanna hear about a little furry animal more than a strange new concept in chemistry.

    This also applies to the "mole's" that appear on ones own face/body.

    You girls did this as an opening to your lesson.

    Question 2.
    Easier teaching strategies?
    1. Stop saying it's a hard/complex/abstract concept to understand, as research has shown students are less likely to engage in difficult tasks for prolonged periods of time. A better strategy would be to use positive reinforcement, saying it's one of the simplest chemistry concepts, which it is.

    2. Introduce the "idea" of a mole, simply as 'A NUMBER'... then clarify, it is, Avagadro's number. Then scaffold in levels from there.

    3. Here is a link to a video which explains it, somewhat well. Hope this helps you improve when teaching this concept again.

    http://www.youtube.com/watch?v=AsqEkF7hcII

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  5. Alexs said..
    Some misconceptions and causes - the mole concept
    Students in high school chemistry are first taught about matter and its properties. This prior knowledge can affect their ideas about quantities (amount of a substance). Thus, how students think about matter and properties is affecting how they think about the amount of a substance (Claesgens & Stacy, 2003).
    A mole is a measure of quantity, one mole of substance is equal to the substances atomic weight
    Krishnan & Howe (1994)
    • Students have an incomplete understanding of what the term "independent units" in the definition of mole stands for, as opposed to the number of atoms in multi atomic molecules.
    • Students often believe the mole to be an exclusive property of the molecules and not the atoms i.e. that students considered that one mole of any substance always related to a certain number of molecules of that substance.
    • Students are confused about the term "quantity" in the definition of mole as meaning a “constant mass" rather than a "constant number".

    - Alex Darmanin

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  6. Are there some easier teaching strategies for this concept?

    Moss and Pabari from Nottingham Trent university (NTU) conducted a study on this particular topic they included misconceptions too.
    Moss and Pabari(2010) summarised some strategies that can implemented in schools to avoid confusion and misconception in schools:

    •Expose all students to the mole early in schools

    •Teach concept at a basic level using words and analogies

    •Develop concept stepwise & review it

    •Show the importance of the mole + its relationship to real-life

    •Provide extra support for students who struggle with maths

    •Use a variety of learning styles and resources to make learning interactive and fun

    •Use a range of assessment tools to do frequent checks on understanding

    •Teachers shouldn’t assume prior knowledge and full understanding of the concept.

    This website was really good, its worth having a look... http://www.heacademy.ac.uk/assets/ps/documents/events/2010/variety/moss.pdf

    Have fun
    Assia Assaad

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  7. A mole is the amount of pure substance containing the same number of chemical units as there are atoms in exactly 12 grams of carbon-12 (i.e., 6.023 X 1023).
    This involves the acceptance of two dictates -- the scale of atomic masses and the magnitude of the gram. Both have been established by international agreement. Formerly, the connotation of "mole" was "gram molecular weight." Current usage tends to apply the term "mole" to an amount containing Avogadro's number of whatever units are being considered. Thus, it is possible to have a mole of atoms, ions, radicals, electrons, or quanta. This usage makes unnecessary such terms as "gram-atom," "gram-formula weight," etc.

    All stoichiometry essentially is based on the evaluation of the number of moles of substance. The most common involves the measurement of mass. Thus 25.000 grams of water will contain 25.000/18.015 moles of water, 25.000 grams of sodium will contain 25.000/22.990 moles of sodium.

    The convenient measurements on gases are pressure, volume, and temperature. Use of the ideal gas law constant R allows direct calculation of the number of moles: n=P V/R T. T is the absolute temperature, R must be chosen in units appropriate for P, V, and T. The acceptance of Avogadro's law is inherent in this calculation; so too are approximations of the ideal gas. Elisa

    Ref: http://www.chemistry.co.nz/mole.htm

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  8. Thank you for your comments. Brian I agree with you what you wrote. It's true teachers and even myself, think it's a hard concept to grasp however like you said positive reinforcement is a great way to start, encouraging the students.
    Will comment on the others soon. Thanks Neelam

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  9. One misconception I have heard is that it is a unit like kg, s & m.

    Luke John Davis

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  10. Hi Luke,

    that is a very common misconception that you have mentioned. To address that, we showed a table during our presentation to show that the mole is a quantity to be measured and the mol is the unit for moles. I guess students get confused sometimes because there is one letter missing and it is pronounced the same.
    -Ponni and Neelam

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  11. Alex thank you for sharing the misconceptions and I agree, they are very common misconceptions among students. As teachers these points should be considered and to do so analogies, visuals and applying every days things perhaps could help students. I think a common problem many students face is the maths side of it and as mentioned by Luke, students think it's like unit kg, s & m. This should be thoroughly explained when first getting into the topic because some students just find it hard, as I did when I first learned about it.
    Thanks everyone for your contribution to this blog :)
    Neelam and Ponni

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  12. What is a mole and why are they used?

    A mole is simply a unit of measurement. Units are invented when existing units are inadequate. Chemical reactions often take place at levels where using grams wouldn't make sense, yet using absolute numbers of atoms/molecules/ions would be confusing, too.

    Like all units, a mole has to be based on something reproducible. A mole is the quantity of anything that has the same number of particles found in 12.000 grams of carbon-12. That number of particles is Avogadro's Number, which is roughly 6.02x1023.

    A mole of carbon atoms is 6.02x1023 carbon atoms. A mole of chemistry teachers is 6.02x1023 chemistry teachers. It's a lot easier to write the word 'mole' than to write '6.02x1023' anytime you want to refer to a large number of things!

    Basically, that's why this particular unit was invented.

    Why don't we simply stick with units like grams (and nanograms and kilograms, etc.)? The answer is that moles give us a consistent method to convert between atoms/molecules and grams. It's simply a convenient unit to use when performing calculations. Okay... you may not find it too convenient when you are first learning how to use it, but once you become familiar with it, a mole will be as normal a unit as, say, a dozen or a byte.

    Elisa :)

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  13. Hi,

    Yes this is a late post, but only because I just found my notebook this morning. The main question I had from the very beginning of your presentation: Does the mole change under different pressures? It's 6.02e23 particles in Standard Atmospheric Pressure, but would that change in any other conditions (i.e. temperature or pressure)?
    Thanks,

    Ethan

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  14. Hi,
    I found this article it goes through why students develop misconceptions and the requirements of chemistry as a subject. the article describes the three levels of chemistry knowledge, and factors that affect learning such as overload of student's memory, concept formation, and language and communication.

    visit http://crins08lerberg.wmwikis.net
    /file/view/Sirhan.pdf

    Shiraz

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  15. Marcus Pabian (16558452)

    I found the presentation of the mole concept in class to be fairly good in that there was a reasonable amount of repetition. I would suggest that it could be improve just a little bit if at the end of each 'test' against the clock the solution to the right answer was revealed step-by-step. This would help to reinforce what has rightly been described as a difficult abstraction.
    I agree with the earlier comment by Sarah Townsend that the effective teaching of this concept is done simulations. From that point of view it maybe useful to add into the lesson a hands-on element using tennis balls and pin-pong balls to symbolise atoms of different size and mass, to allow students to 'grasp' the conceptual difference between number, mass and volume.

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