Sebanyak 1 mol gas helium (Mr = 4) memiliki suhu 27c. Tentukan: a. Energi kinetik rata-rata partikel dan b. Energi dalam gas

diket
n = 1 mol
mr = 4
T = 27 c + 273 = 300 kelvin

dit
a.Ek = .....?
b. Energi dalam .... ?

jawab

Ek = 1/2 m.v^2 rms
v rms = akar 3kT/m molekul

m= n .mr = 4 .1 mol = 4 kg
v rms = akar 3.1,38 × 10^-23.300/ 4
v rms = 3105 ×10^-24

Ek = 1/2 . 4 .3105 .10^-24
Ek = 6210× 10^-24

b. U = 3/2 nRT karena T = 300
U = 3/2.1.8,31. 300 K
U = 450 × 8,31
U = 3739,5 Joule