2 more chem questions that im not sure about

Discussion in 'Community Discussion' started by macman2790, Jun 20, 2007.

  1. macman2790 macrumors 6502a

    macman2790

    Joined:
    Sep 4, 2006
    Location:
    Texas
    #1
    here it is:

    Consider the balanced chemical equation: Ca(OH)2(aq) + 2HCl(aq) → CaCl2(aq) + 2H2O(l). How many moles of HCl remain if 0.1 mol of Ca(OH)2 react with 0.4 mol of HCl?


    i think the answer is 0.3 mol, but im not sure

    also im not so sure about this one, if anyone gets a chance.

    A flask contains pure Ne at a pressure of 0.50 atm. If Ar is added to the flask until there is three times as much Ar as Ne, the total pressure in the flask is:

    thanks
     
  2. Abstract macrumors Penryn

    Abstract

    Joined:
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    #2
    Are you going to ask us about every chemistry question you have?
     
  3. Hummer macrumors 65816

    Hummer

    Joined:
    Feb 3, 2006
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    Queens, New York NY-5
    #3
    Try putting them all in one thread like I did.
     
  4. macman2790 thread starter macrumors 6502a

    macman2790

    Joined:
    Sep 4, 2006
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    #4
    no, im just in a hurry, sorry i have too many and this are the last 2 i have questions on
     
  5. Jasonbot macrumors 68020

    Jasonbot

    Joined:
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    #5
    Well the ratio is 1:2 so the limiting reagent is the HCl and so the Ca(OH)2 reacts fully but only 0.2 moles of HCl will react. Therefore 0.1+(0.1*2)=0.3 moles that react completely and so 0.2 moles DO NOT react.

    I can't remember the formula for volume now, I think it's n=m/V

    remember pressure is always a ratio as in P1/V1=P2/V2
    so:
    0.5/V1=P2/V2

    But please remember I'm unsure of the equation to find V (sorry)...
     

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