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Destroyer Gchem Questions

Discussion in 'DAT Discussions' started by Predentknight, Jun 5, 2008.

  1. Predentknight

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    #46:

    I dont understand why C is true. The answer choice states that Hydrogen bonding will cause the solid-liquid line to be skewed to the left in a phase of P vs. T.

    My reasoning: Hydrogen bonding increases solubility or like dissolves like , therefore wouldnt the line shift to the right in the liquid phase. I did not full grasp the destroyer solution. Can someone please clarify.

    #56:

    Why would the Eo for for Cr be positive if it is being oxidized. I thought the more positive Eo indicates being reduced.???

    #64:

    This problem deals with vapor pressure. Now please correct me if I am wrong but a substance boils when the vapor pressure equals atmospheric presssure.

    This problem states that when KOH is dissolved in water, we see a decrease in the vapor pressure of the solution.

    My reasoning: When KOH dissolves in water doesnt that increase the boiling point. inturn wouldnt this mean a higher vapor pressure, because the solution will now boil at a higher temperature?? very confused.
     
  2. Mstoothlady2012

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    sorry i dont have # 46 in my book

    # 56 - if you look at the both equations the Eo for Co+2 ---> Co is -0.28 which is higher than Eo for Cr+3---> Cr, which means Co+2 will go under reduction the way it is written where else the other equation will go under oxidation in opposite direction
     
  3. Mstoothlady2012

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    no...the higher the vapor pressure, lower the boiling point. I know what you mean it confuses me too.
     
  4. DanNuch

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    easy way to think of it is just that the higher the vapor pressure (the more vapor emitted from the liquid), the more the vapor wants to be in the gas state, and thereby requires less heat (energy) to boil the liquid... and thereby boiling at a lower temperature

    i guess that still doesnt sound to easy, maybe even more complicated, but thats what i think
     
  5. Mstoothlady2012

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    This is how I think of it. When you add solute to the solvent it lowers the vapor pressure, so now it will take higher amount of heat to raise that vapor pressure to make it equal to the atmospheric pressure than it originally was.
     

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