We say that Temperature is basically average kinetic energy so can't we say that unit of temperature is Joules??

1 Answer
May 12, 2017

No, we don't. We say that temperature is PROPORTIONAL to the average kinetic energy...

K_(avg) prop TKavgT

More explicitly, from the so-called equipartition theorem,

K_(avg) = N/2nRTKavg=N2nRT,

where NN is the number of degrees of freedom (unitless), nn is the number of "mol"mols of gas, and RR is the universal gas constant.

When RR has units of "J/mol"cdot"K"J/molK and TT has units of "K"K... the units of kinetic energy are therefore

cancel"mols" xx "J/"cancel"mol"cdotcancel"K" xx cancel"K" = color(blue)("J")

even though we continue forevermore to use units of "K" for absolute temperature.