conditii normale inseamna presiune de 10^5 Pascali si 0grade Celsius.
Energia interna (U)= mol*C*T ; C-caldura molara la volum constant
inlocuiesti T cu p*V/mol*R ;p-presiune, V-volum, R-constanta gazelor ideale
==>U=mol*3/2*R*p*V/R/mol
U=3/2 p*V= 3/2 *1cm^3*10^5Pa
1cm^3=1*10^-4m^3==> U=15 J
