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Homework Help: Need Help

  1. Jun 2, 2007 #1
    can someone please answer, and show me how, the following questions.

    1. Outer space is not toally empty, there is about one atom of hydrogen per cubic centimeter and the temperature is 2.7 K. What is the speed of these hydrogen atoms, and what is the pressure?

    2. calculate the number of molecules/m cubed in an ideal gas at 273 K and 1atm

    3. What is the mass of air in a room that has dimensions of 12m x 6m x 2.4 m.
    assume that the air is 79% nitrogen (N2) and 21% oxygen (02)

    4. What is the speed of a helium atom in a childs baloon at room temperature (20 degrees centigrade).
  2. jcsd
  3. Jun 2, 2007 #2

    2.7 K is not because of the gas in space.
    its the background radiation, which is like a 2.7 K black-body's radiation.

    sorry, i have no time to answer the rest.
  4. Jun 2, 2007 #3


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    Welcome to PF, Wily. This is pretty clearly a homework question, and therefore belongs in that section. Also, we do not do the work for you. The object here is to teach you how to do it yourself. In that regard, the second part of your post is proper; the first part is not. Remember the guidelines that you agreed to upon registering.
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