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Homework Help: Thermal concepts questions (chem related)

  1. Jan 9, 2010 #1
    I know these aren't exactly physics problems but I'm being asked them in physics so...
    1. The problem statement, all variables and given/known data
    1) As lead melts there is a change in it's...
    Temperature
    Heat of fusion (what I now think it is)
    Avg molecular KE (what I thought it was)
    Avg molecular PE

    2)In a room there is 250kg of air, in the avg molecular mass of air is 28.8g/mol (.0288kg) how many particles of "air" is in the room?

    2. Relevant equations
    1) none

    2) n=m/M
    3. The attempt at a solution
    1) look above in parentheses

    2)
    n=250/.028
    8860.55
     
  2. jcsd
  3. Jan 9, 2010 #2

    ideasrule

    User Avatar
    Homework Helper

    Your answers to #1 are wrong. Check your textbook for an explanation of the heat of fusion. I can explain it here, but it's too important a concept to cover thoroughly in one forum post.

    For #2, you found the number of moles. The question asks for the number of actual particles.
     
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