Work

[Nadia Nichol]

This is from a while ago but I am curious if there are any other phrasing or scenarios in which it is necessary to differentiate - work and + work other than knowing whether something is being worked on or doing the work? Which is positive and which is negative?

[Jeannie Kennedy 3F]

Hi! I guess you could look at work in terms of expansion. For example, when a system expands against external pressure, then work will be positive because it is doing work on its surroundings. Whereas, when the surroundings compress a system then work is negative because energy is transferred from the surroundings to the system.

[Cartor_Crisp_2A]

Work can be viewed in a similar manner as enthalpy, where a negative sign indicates a loss of energy and a positive sign indicates a gain of energy (in the system). The only difference for work is that a negative sign indicates work done by the system, and a positive sign indicates work done on the system.

[noree_jauregui]

To add on, you can find work if given the internal energy and enthalpy. With this, you can use the equation delta U=q+w and determine if the w is less than 0 or greater than 0. Questions will probability ask if the work is done on or by the system and this equation will help you answer.