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Homework Help: Mixture or substance?

  1. Oct 23, 2005 #1
    A mixture is defined as 2 substances that are arbitirarily combined. They are either homogenous or heterogenous.

    A substance is defined as being homogenous and has definite, fixed composition that is NOT arbitrary.

    On some classwork we did, this following was stated as being true:

    wood is a.....answer: mixture

    sodium chloride is a...... answer: mixture

    I disagree; wood is a substance because it has a fixed composition by definition. And since sodium chloride is a compound, it is not a mixture either; it is a substance.
    the choices for classification on the worksheet was "mixture" or "substance".
    I am confused...please help.

    thanx
     
  2. jcsd
  3. Oct 23, 2005 #2

    Pengwuino

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    Wood is not a substance. There is no chemical compound that can be called "wood". A wood is a large mixture of various chemicals and compounds.
     
  4. Oct 23, 2005 #3
    thank you!!!!

    How about sodium chloride then? it is a substance?
     
  5. Oct 24, 2005 #4

    Pengwuino

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    Yes.. its ordinary table salt.
     
  6. Oct 24, 2005 #5
    Think of it this way, a substance can not be physicly broken down into somthing else.

    A mixture can be physicly seperated (Like filtering a mixture)
     
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