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-   -   How can I find temperature? (https://www.askmehelpdesk.com/showthread.php?t=435927)

  • Jan 16, 2010, 03:07 PM
    hslove142331
    How can I find temperature?
    To what temperature must 280mL of CO2 be cooled for its volume to decrease to 130mL if initial temperature is 11C ?

    How can I find temperature?
    Do we have any formula for this problem?

    Thank you
  • Jan 17, 2010, 09:00 AM
    Unknown008

    Yes, you basically start with the equation:

    PV=nRT

    P = pressure of gas
    V = volume of gas
    n = no. of moles of gas
    R = ideal gas constant
    T = temperature of gas in Kelvin

    the ideal gas law equation.

    Now, since it's a closed system, the number of moles n is a constant.

    Then, you can write it as:



    Now, since you have two different situations, with the same constant, you may write:



    Here, since the pressure remains the same, the P crosses out;



    Then, replace:
    Initial volume = 280 mL
    Initial temperature = 11+275 = 286 K
    Final volume = 130 mL



    Solve for T2, the final temperature in Kelvin. Then convert back to degrees celsius if you want or if it is asked.
  • Jan 18, 2010, 02:15 PM
    hslove142331
    Initial temperature = 11+275 = 286 K

    on here I thought 273, Is it just same as 275?

    so T2 going to be -140.15C ? Correct?
  • Jan 20, 2010, 07:36 AM
    Unknown008

    Yes, it's 273, I made a typo... last time. :o

    Yes, you got the answer! :)
  • Jan 20, 2010, 01:54 PM
    hslove142331
    Thank you so much! Your teaching is more better than ma teacher.
  • Jan 21, 2010, 06:22 AM
    Unknown008

    Lol, the only difference is that I may not be always on time to answer you. I'm myself quite busy with my homework...

    Thanks for the compliment! :)

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