## Kelvin

$\Delta S = \frac{q_{rev}}{T}$

Lauryn Jordan 1F
Posts: 76
Joined: Fri Sep 29, 2017 7:07 am

### Kelvin

Do you always have to use kelvin with regards to temperature?

Sarah Sharma 2J
Posts: 33
Joined: Fri Sep 29, 2017 7:05 am

### Re: Kelvin

Yes, always convert to Kelvin when calculating for entropy. Also, when looking at the units for some of the constants, it will tell you whether to use Celsius or Kelvin! Usually Kelvin though!

aaron tang 2K
Posts: 49
Joined: Thu Jul 27, 2017 3:01 am

### Re: Kelvin

Look at the signs throughout the problems, but in most cases, you should write in kelvins just to keep it constant throughout the problem.

andrewr2H
Posts: 29
Joined: Fri Sep 29, 2017 7:05 am

### Re: Kelvin

Unless specified otherwise, it is generally safe to perform calculations with temperature in terms of Kelvin. Even in the case of a specific heat equation or of the like, most often the calculation involves using change(difference) in temperature. Because degrees K = degrees C + 273, the difference will always be the same whether you perform the calculation in terms of K or C. For example, 298 K - 300 K and 25 degrees C - 27 degrees C both yield the value of -2. But in general it is good to always double check units and see if and where they cancel out when doing problems.

Charles Ang 1E
Posts: 50
Joined: Thu Jul 13, 2017 3:00 am

### Re: Kelvin

For the homework problems, it is safe to assume that you always have to convert to Kelvin. However, if you are finding the change in temperature, you can choose to stay in C rather than K because 273 will be added to both addends.