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Homework Help: Change in Internal Energy

  1. Aug 5, 2007 #1
    1. The problem statement, all variables and given/known data
    One mole of hydrogen gas is heated from 278 K to 390 K at constant pressure. Hydrogen has a specific heat of 43.6 J/mol*K. The universal gas constant is 8.31451 J/K mol. Calculate the change in the internal energy of the gas. Answer in units of J

    2. Relevant equations

    Change in Internal energy = (1.5)nRT
    n= number of moles
    R= universal gas constant
    T= change in temperature

    3. The attempt at a solution
    (1.5)(1 mol)(8.31451 J/k mol)(112 K)

    what am i doing wrong??
    the website i have to submit my hw to says it's incorrect...:eek:
  2. jcsd
  3. Aug 6, 2007 #2
    I think thats right... You may want to look at the significant figures though.
  4. Aug 6, 2007 #3
    noo def not
    my teacher HATES significant digits, so we're just supposed to carry it out about 5 decimal places
    grr i can't figure this one out :(
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