To estimate the gas constant of agas at higher tempeature and pressure whcih relation we will use:

1. R =Universal gas constant/molecular weight

2. R =C p-Cv

Dear student,

R = 8.314/M is always a constant irrespective of pressure and temperature

CP - CV is a function of temperature and this is a better estimate of R for ideal gas at high temperatures

for ideal gas first option is preferrable.

all the best !!!