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Homework Help: Chemistry: First principle of thermodynamics

  1. May 20, 2017 #1


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    Gold Member

    1. The problem statement, all variables and given/known data

    2. Relevant equations
    First principle of thermodynamics: E=q+w

    3. The attempt at a solution
    ∴Endothermic (absorb heat from surrounding)

    (a) false (from surrounding to the system)
    (b) false (does work by surrounding)
    (c) true
    (d) true

    the answer states only option b is false... why option a is true?
    Thank you very much!
  2. jcsd
  3. May 20, 2017 #2
    q=-17 kJ means that heat flows from the system to the surroundings. So "a" is not false.

    And why are you using E=q+w=-17+21=4kJ>0 to say that
    ∴Endothermic (absorb heat from surrounding)?
  4. May 20, 2017 #3


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    Gold Member

    I see. thanks.
  5. May 22, 2017 #4


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    Science Advisor

    It is impossible for only option B to be false. If B is false E is also false.
  6. May 22, 2017 #5


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    Staff: Mentor

    Good catch.
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