## Work

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

Valeria Viera 1B
Posts: 60
Joined: Fri Apr 06, 2018 11:05 am

### Work

There are so many work equations and equations derived from others
How do you know which to use? Do you need to memorize each or know how to derive them?

Sophia Diaz - Dis 1B
Posts: 73
Joined: Fri Apr 06, 2018 11:02 am
Been upvoted: 1 time

### Re: Work

When it comes to work, you don't need to memorize the derivative/integral equations. We were only shown them in order to understand where they came from and how to solve for what is missing.

When it comes to the rest of the work equations, most of them are shown on the equations worksheet when we have an exam.
However, It is definitely necessary to remember when to use which equation when conditions changes. For example, know which work equation to use when pressure is constant versus when the temperature is constant (Also keep in mind irreversible vs reversible).

Luis_Yepez_1F
Posts: 50
Joined: Fri Sep 28, 2018 12:18 am

### Re: Work

I would focus on the ones showed on the constants page that is given each test. Also as mentioned, we don't need to know any of the ones that have derivatives or the integrals, these serve mainly as proofs.

Isabelle Fontanilla 1I
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

### Re: Work

So far, the only type of work we talked about is work through expansion/compression. For this, you only really need to remember(and understand) the work equation at constant pressure (w=-PΔV) and the work equation for reversible and isothermic configurations (w=-nRTln(V2/V1)).

404982241
Posts: 47
Joined: Fri Sep 28, 2018 12:17 am

### Re: Work

Just like, look at the givens.

Jason Ye 2I
Posts: 33
Joined: Fri Sep 28, 2018 12:22 am

### Re: Work

Look at the given units and variables

Mark 1D
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

### Re: Work

whichever best suits and demands and variables of the question

Pritish Patil 1K
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

### Re: Work

There are charts on the internet that simplify which equation to use for a certain situation (ex: isobaric, isothermal, etc). Hope this helped!

Jack DeLeon 1B
Posts: 30
Joined: Fri Sep 28, 2018 12:20 am

### Re: Work

most of the equations will be given to us on the equation sheet, and it is important to know which one to use in a given situation