Chemistry · Ch 4 — Chemical Thermodynamics
Sign conventions of W and Q
Sign conventions of W and Q
The energy changes for the system are considered hereafter. The energy entering the system from the surroundings has a positive value, while the energy leaving the system and flowing into the surroundings is negative. This is shown in Fig. 4.6.
Drawn by us to help you understand the concept clearly, and verified to make sure it's accurate. For exams, practice from your textbook's own diagram.
What this figure shows. A grey box labelled SYSTEM with four horizontal arrows. On the left (work side): an inward arrow labelled On the system and an outward arrow labelled By the system, beside the stack +W / surroundings / -W. On the right (heat side): an inward arrow labelled Heat absorbed and an outward arrow labelled Heat released, beside the stack +Q / surrounding / -Q. Energy entering the system is positive; energy leaving it is negative. (The …
: Heat is absorbed by the system from the surroundings.
: Heat is released by the system to the surroundings.
: Work is done on the system by the surroundings. …