Question

in the ideal gas equation pV=nRT, could on use values of ceulsius temperature instead of thermodynamic temperature by using an appropriate value R of the molar gas constant ?

Answer 1

i don't think so... clesius can be a negative number for example. When doing physics, you should always use the SI-System - saves you a lot of troubles..

Answer 2

No, you cannot use Celsius for the ideal gas law.

Almost all physics equations are developed based on the principle of proportionality: if you double one quantity, what happens to some other quantity? If you "double" a Celsius temperature (say from 35 to 70), you are NOT doubling the absolute temperature (or absolute kinetic energy of the particles in the gas). So if you use Celsius, you are not in agreement with the concept of proportionality upon which the ideal gas law is based.

I hope that solidifies your understanding!