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Difference between a homogenous mixture and a heterogeneous mixture

  1. Sep 8, 2004 #1
    Hello all

    I was just wondering what is the difference between a homogenous mixture and a heterogeneous mixture. For example:

    a. sea water
    b. tomato juice
    c. gasoline
    d. milk

    What type of mixtures are these?

    Also, what do we classify fire as (solid, liquid, gas)?

    Any help would be greatly appreciated

  2. jcsd
  3. Sep 8, 2004 #2


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    Staff Emeritus
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    Gold Member

    I would call them all homogeneous, with the possible exception of tomato juice. A homogeneous mixture is one which is uniform at "macroscopic" levels of observation. Yes, this depends on your definition of 'macroscopic' - a term that's not really well defined. But here's an accepted rule : if you can detect differences of the length scale that can be discerned by the naked eye (at the least distance of distinct vision, typically ~ 10cm or 4 inches), then it's heterogeneous.

    Fire is a mixture of gases and solids (mostly colloidal sized particles of unburnt carbon).
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