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The decrease in volume requires the surroundings do 7.6 J of work on the gases

  1. Oct 30, 2012 #1
    1. Reacting 50 mL of H2(g) with 50 mL of C2H4(g) produces 50 mL of C2H6(g) at 1.5 atm. If the reaction produces 3.1 x 10^2 J of heat and the decrease in volume requires the surroundings do 7.6 J of work on the gases, what is the change in internal energy of the gases?




    2. Change in Internal Energy = Q(heat energy) + W(work)
    Work = - P x (change in volume)




    3. I know how to apply these equations but have no idea about the " 7.6 J of work" part.
     
  2. jcsd
  3. Oct 30, 2012 #2

    tiny-tim

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  4. Oct 30, 2012 #3
    Thanks tiny tim :) This is what I got:

    (-310 J) + (7.6J)
    = 302.4 J = -3 x 10^2 J
     
  5. Oct 30, 2012 #4

    tiny-tim

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    looks right :smile:
     
  6. Oct 30, 2012 #5
    sweet, thanks
     
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