Problems and Solutions on Thermodynamics and Statistical Mechanics

Statiaticd Physica 205

• 
  
  
  
  • Thus Er,p = 0, Er,o = A(l + 1) 1 = 2A = 180 K, giving
  
  
  
  

From equipartition of energy, we have

• 3
  Et = -kT = 30 K.
  2

The average energy of a molecule is

• E = E, + E, = 165 K.

2041

The graph below shows the equilibrium ratio of the number of ortho-

hydrogen rnolecules to the number of parahydrogen molecules, as a function

of the absolute temperature. The spins of the protons are parallel in or-

thohydrogen and antiparallel in parahydrogen.

(a) Exhibit a theoretical expression for this ratio as a function of the

temperature.

(b) Calculate the value of the ratio for 100 K, corresponding to the

The separation of the protons in the hydrogen

(UC, Berkeley)

point F on the graph.

molecule is 0.7415k

Fig. 2.11.