Quantitative relationship between entropy and number of microstates The connecti
ID: 978335 • Letter: Q
Question
Quantitative relationship between entropy and number of microstates The connection between the number of microstates, W, and the entropy, S, of a system is expressed by the Boltzmann equation where k is the Boltzmann constant per molecule (particle), 1.38 × 10-23 J/ K-particle). From this equation the entropy change, for a system can be related to the change in the number of microstates as Wfi Winitial where Wfinal in the final number of microstates and Winitial is the initial number of microstates. Part B A gaseous system undergoes a change in temperature and volume. What is the entropy change for a particle in this system if the final number of microstates is 0.458 times that of the initial number of microstates? Express your answer numerically in joules per kelvin per particle. AS J/(K particle)Explanation / Answer
B)
given
Wfinal / Winitial = 0.458
also
boltzmann constant = 1.38 x 10-23 J / K .particle
now
dS = k x ln ( Wfinal / Winitial )
using the given values
we get
dS = 1.38 x 10-23 x ln 0.458
dS = -1.0776 x 10-23 J / K.particle
we know that
for a reaction to be spontaneous
dG < 0
now
dG = dH - TdS
so
dH - TdS = 0
(-50 ) - ( T x -0.3 ) < 0
-50 + 0.3T < 0
0.3T - 50 < 0
0.3T < 50
T < 166.67 K
so
the temperature is 166.67 K