What is q equal to in the second law of thermodynamics?


Moderators: Chem_Mod, Chem_Admin

Kobe_Wright
Posts: 83
Joined: Fri Sep 28, 2018 12:16 am

What is q equal to in the second law of thermodynamics?

Postby Kobe_Wright » Wed Feb 06, 2019 3:34 pm

As in how would it be presented in a problem and in what units?

Lauren Huang 1H
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

Re: What is q equal to in the second law of thermodynamics?

Postby Lauren Huang 1H » Wed Feb 06, 2019 4:30 pm

The second law of thermodynamics states that delta S=q/T=nRln(V2/V1). So q=nRTln(V2/V1) if you multiply both sides by temperature. I believe the unit for q is Joules.

Summer de Vera 2C
Posts: 65
Joined: Fri Sep 28, 2018 12:16 am

Re: What is q equal to in the second law of thermodynamics?

Postby Summer de Vera 2C » Thu Feb 07, 2019 3:45 pm

Lauren Huang 1H wrote:The second law of thermodynamics states that delta S=q/T=nRln(V2/V1). So q=nRTln(V2/V1) if you multiply both sides by temperature. I believe the unit for q is Joules.

Wouldn't you have to divide rather than multiply both sides by T?

BenJohnson1H
Posts: 68
Joined: Fri Sep 28, 2018 12:17 am

Re: What is q equal to in the second law of thermodynamics?

Postby BenJohnson1H » Sat Feb 09, 2019 7:59 pm

T can be completely canceled out. Think of it as the -q=w. Because the function for work involves the multiplication of T but deltaS is q/T, the q is simply taken out and the negative sign is omitted.

Kobe_Wright
Posts: 83
Joined: Fri Sep 28, 2018 12:16 am

Re: What is q equal to in the second law of thermodynamics?

Postby Kobe_Wright » Fri Mar 08, 2019 3:48 pm

Summer de Vera 2C wrote:
Lauren Huang 1H wrote:The second law of thermodynamics states that delta S=q/T=nRln(V2/V1). So q=nRTln(V2/V1) if you multiply both sides by temperature. I believe the unit for q is Joules.

Wouldn't you have to divide rather than multiply both sides by T?

I believe its divide;.

Kobe_Wright
Posts: 83
Joined: Fri Sep 28, 2018 12:16 am

Re: What is q equal to in the second law of thermodynamics?

Postby Kobe_Wright » Fri Mar 08, 2019 3:48 pm

BenJohnson1C wrote:T can be completely canceled out. Think of it as the -q=w. Because the function for work involves the multiplication of T but deltaS is q/T, the q is simply taken out and the negative sign is omitted.

Thanks Ben that helps!!!


Return to “Concepts & Calculations Using Second Law of Thermodynamics”

Who is online

Users browsing this forum: No registered users and 1 guest