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Homework Help: Need help badly

  1. Apr 25, 2005 #1
    Here's the problem:

    The density of water at 4oC is 1.00x103kg/m3. What is the change in density if the water is heated to 85oC? Remember that the change will be the final density minus the initial density. Assume a coefficient of volume expansion of 2.10x10-6/oC.

    Now, I have tried using a standard mass of 1000KG and solving the problem that way, however I am way off... please help
  2. jcsd
  3. Apr 25, 2005 #2


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    By definition:
    {Coefficient of Volume Thermal Expansion} = α = (-1/ρ)(Δρ/ΔT)
    ::: ⇒ Δρ = -αρΔT
    Use values given in problem statement for terms on the right to calculate "Δρ".

  4. Apr 25, 2005 #3


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    Homework Helper

    Calculate the volume expansion assuming an initial volume V_0. Add that to the initial volume to find a final volume. Multiply the initial density times V_0 to get an initial mass expressed in terms of V_0. Divide that mass by the new volume. The V_0 factors will all divide out. It will work.
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