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So my answer was 3 and it was wrong, And i really would like to know what is the correct answer, after giving it some thought, I think the answer is 4 because indeed it is easier to control the system than surroundings, can you please assure it that it's D.

I appreciate any help

Stormin nn
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    In my judgment, this question is totally idiotic. Who cares? will knowing the answer to this question, whatever it is, in any way improve your ability to correctly analyze the behavior of any specific situation? – Chet Miller Oct 17 '20 at 16:18
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    I agree, but still :) – Stormin nn Oct 17 '20 at 16:21
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    @ChetMiller Curiously enough, I would not entirely agree with the answer (D). For instance, in a typical adiabatic bomb calorimetry experiment we monitor the change in temperature of the jacket surrounding the bomb in which the reaction takes place. The temperature change of the jacket is due to exchange of heat with the bomb. One can argue about semantics, but the jacket could be regarded as the surroundings in this case. – Buck Thorn Oct 17 '20 at 18:20
  • Why would it - how could it - be viewed from any other perspective? – Robbie Goodwin Oct 18 '20 at 01:28
  • The basis of this question seems silly to me, because you're going to focus on the heat and work exchange between the system and the surroundings, which means it is all a matter of sign convention (i.e. this simply defines the physical meaning of $q>0$ and that of $w>0$). Somehow the question seems to be saying that, say, defining $q$ to be the heat change in the surroundings would necessitate measuring the entire heat change in the surroundings from all factors, which is absurd. – Ian Oct 18 '20 at 16:35
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    Does this answer your question? Why do chemistry and physics have different sign convention in thermodynamics? – Mithoron Oct 19 '20 at 23:02

1 Answers1

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The problem is in the word "always". The statement "Work and heat energy are always viewed from the perspective of the system?" is wrong. Please inform your teacher that is true in the chemist's world only- and chemists did not invent thermodynamics.

Chemists have adopted a different convention than physicists. All we have to do is to be aware of the context.

Recall the First Law of Thermodynamics, which has 2 different equivalent statements.

In some books it is

$$∆U=q-w$$

and in some it is

$$∆U=q+w$$

Why, because the word "always" is not correct.

KingLogic
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AChem
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    "Please inform your teacher that is true in the chemist's world only". This statement is incorrect. While both chemists and physicists usually reference heat and work relative to the system, both chemists and physicists can switch to referencing them relative to the surroundings if that makes sense for the particular set-up they are analyzing. Ironically, you're making the same mistake the problem did: making a broad, incorrect generalization. – theorist Oct 17 '20 at 23:54
  • By way of comparison, according to the international standard ISO 80000 Quantities and units – Part 5: Thermodynamics, $\Delta U=Q+W$ where $Q$ is amount of heat transferred to the system and $W$ is work done on the system provided that no chemical reactions occur. This applies to physicists as well as chemists. –  Oct 18 '20 at 08:05