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Why does water have a density?

  1. Mar 19, 2010 #1
    Ok density of water is 1000 g/ 1 L

    I don't know isn't this 1 L composed completely of water. This is confusing me. Do find the concentration you have to find the moles and divide by 1 L. 1000/18=55 M . I thought concentration of pure water you can't find because the solution is complete water. I hope you understand what I mean. Thanks :smile:
  2. jcsd
  3. Mar 19, 2010 #2


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    Are you confusing density with concentration? There is 1000g of water in a volume of 1L if that 1L contains entirely water...
  4. Mar 20, 2010 #3
    your math and equations are right. the density is just 1 kg/L as you have shown. The concentration of moles / liter is actually moles of solute / liter of solvent. so technically the solute mole would be 0, the 55 mole is actually the solvent mole. So again technically it's 0 mole /1 L so it's 0 still. The 55 is useless, and unnecessary. Just a definition thing, dont fuss over it too much. You got the big stuff right
  5. Mar 21, 2010 #4
    water is a universal liquid or solution or whatever you can call it.

    Accept its density as a universal fact !!


    your theory is right though but everything which we come across today has already been proved, hasnt it ?????? !!!!!!!!!
  6. Mar 21, 2010 #5
    The intent of the pre-SI system was to have 1 liter of pure water (at 4 C) weigh exactly 1 kg (at standard gravity; representing 1 kg of mass). In fact, this was still too imprecise for a metric standard. Today, the standard is a 1 kg platinum-iridium cylinder kept at a secure location in France.

    http://www.essex1.com/people/speer/mass.html [Broken]
    Last edited by a moderator: May 4, 2017
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