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### Work

Posted: Sun Feb 16, 2020 9:22 pm
When is work positive/negative

### Re: Work

Posted: Sun Feb 16, 2020 9:24 pm
When a system does work, work is positive
When work is done on a system, work is negative

### Re: Work

Posted: Sun Feb 16, 2020 9:28 pm
when something is being compressed, work is done by the system, so it is positive. When something is expanding, work is done on a system, so it is negative.

### Re: Work

Posted: Sun Feb 16, 2020 9:36 pm
Positive would occur when the work is actually able to be done. When there is work being done on the system itself, the work would actually be negative.

### Re: Work

Posted: Sun Feb 16, 2020 9:53 pm
When there is work done on a system, the work is negative. However, when the system itself does work, then work is positive.

### Re: Work

Posted: Sun Feb 16, 2020 9:58 pm
Matthew Chan 1B wrote:When there is work done on a system, the work is negative. However, when the system itself does work, then work is positive.

Sorry, I meant it the other way around haha! Work is negative when the system does work. When the system has work done on it, then work is positive. Sorry about the typo!

### Re: Work

Posted: Sun Feb 16, 2020 10:07 pm
In relation to gases, work is done on the system when compression occurs, and the system does work when expansion occurs. The former is positive and the latter is negative.

### Re: Work

Posted: Sun Feb 16, 2020 10:16 pm
In thermodynamics, work is the energy transferred from the system to the surroundings. So, when the system transfers energy to the surroundings by doing work, the work is negative. When the surroundings transfer energy to the system by doing work on it, the work is positive.

### Re: Work

Posted: Sun Feb 16, 2020 10:31 pm
An exception to the expanding concept is when the external pressure is 0. Then, a system can expand without doing any work (w=0)

### Re: Work

Posted: Tue Feb 18, 2020 6:26 pm
When work as done on a system it is positive (because its like taking in work potential by having work done on it). When a system does work then the value is negative (because there is an output of work, like when a reaction is exothermic and releasing heat and the heat or enthalpy value is negative).

### Re: Work

Posted: Tue Feb 18, 2020 10:22 pm
When a system does work then work is positive, but when work is being done on a system then work is negative.

### Re: Work

Posted: Sun Feb 23, 2020 11:32 pm
Work done on the system is positive. Work done by a system is negative.

### Re: Work

Posted: Tue Feb 25, 2020 9:00 pm
on system= positive, by system=negative

### Re: Work

Posted: Sun Mar 01, 2020 9:00 pm
If the system is doing work on the surroundings, like when the volume of something is expanding or heat is being released; but if something is being compressed or heat is being put in, then the surroundings are doing work on the system.

### Re: Work

Posted: Sun Mar 01, 2020 9:11 pm
Work done on system is positive, work done by the system is negative.