### P1/P2

Posted:

**Wed Feb 12, 2020 9:11 am**Why is it P1/P2 for delta S and V2/V1?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=133&t=59255

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Posted: **Wed Feb 12, 2020 9:11 am**

Why is it P1/P2 for delta S and V2/V1?

Posted: **Wed Feb 12, 2020 11:01 am**

Volume and pressure are related inversely, so V=1/P. So when you use the delta S equation, you can replace V with the inverse of P, which results in nRln(P1/P2).

Posted: **Wed Feb 12, 2020 2:07 pm**

Using the Ideal Gas Law we know that PV=nRT where P and V have an inverse relationship. This is why we can use P1/P2 in place of V2/V1.

Posted: **Wed Feb 12, 2020 2:47 pm**

Because P and V has an inverse relationship. If you increases one, one wil decreases (PV=nRT)

Posted: **Thu Feb 13, 2020 12:51 pm**

Katie Kyan 2K wrote:Using the Ideal Gas Law we know that PV=nRT where P and V have an inverse relationship. This is why we can use P1/P2 in place of V2/V1.

This is called Boyle's Law.

Posted: **Sat Feb 15, 2020 3:06 am**

Pressure and volume always have an inverse relationship, so it's P1/P2 instead of vice versa.

Posted: **Sat Feb 15, 2020 3:41 pm**

Boyle's Law proves that volume and pressure are inversely related.

Posted: **Sat Feb 15, 2020 3:56 pm**

Because in the ideal gas law, P and V are inversely proportionate to each other.

Posted: **Sat Feb 15, 2020 5:25 pm**

Pressure and volume are inversely proportional to each other therefore depending on what you're given, the ratio will always be V2/V1 or P1/P2.

Posted: **Sat Feb 15, 2020 10:11 pm**

Pressure and volume are inversely related (when volume increases, pressure decreases, and vice versa). Therefore, it is P1/P2 and V2/V1.

Posted: **Sat Feb 15, 2020 10:21 pm**

Rita Chen 1B wrote:Why is it P1/P2 for delta S and V2/V1?

According to Boyle's law, pressure and volume are inversely related. As such, if one variable increases, the other variable decreases. Since these two variables are in an inverse relationship, their ratios must also be inverses of each other. Thus, for delta S, it is V2/V1 and P1/P2.