## Celsius or Kelvin

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

Abigail Urbina 1K
Posts: 102
Joined: Thu Jul 27, 2017 3:01 am

### Celsius or Kelvin

If asked to calculate the changes in entropy and we are given temperature in terms of Celsius, do we always have to convert the temperature to be in terms of Kelvin? I know both can technically be considered correct, but is there a preferred method?

Kevin Ru 1D
Posts: 50
Joined: Thu Jul 13, 2017 3:00 am

### Re: Celsius or Kelvin

You should convert to Kelvin as it is no longer ΔT in the equation, but T (The general formula for change in entropy being ΔS = qrev/T).

905022356
Posts: 48
Joined: Mon Oct 02, 2017 7:19 am

### Re: Celsius or Kelvin

When in doubt, it is always best to convert the temperature to Kelvin by adding 273.15.

Jason Liu 1C
Posts: 52
Joined: Fri Sep 29, 2017 7:04 am

### Re: Celsius or Kelvin

For problems with ΔT, you can use either Celsius or Kelvin because the difference between the temperatures will be the same. However, for problems with just T, you should generally use Kelvin because that is the SI unit.

Erica Nagase 1H
Posts: 30
Joined: Sat Jul 22, 2017 3:00 am

### Re: Celsius or Kelvin

For problems with ln$\frac{T2}{T1}$, temperature has to be in K because the conversion factor is additive (+273) and won't cancel out. In comparison, the units don't really matter for problems with ln$\frac{V2}{V1}$ or ln$\frac{P1}{P2}$ because the conversion factors are multiplied (like x1000mL) and cancel out.

Cynthia Bui 2H
Posts: 30
Joined: Fri Sep 29, 2017 7:05 am

### Re: Celsius or Kelvin

Definitely Kelvin.