In: Chemistry
The force constants for F2 and I2 are 470. and 172 Nm−1, respectively. The atomic masses in amu are as follows: 19 F - 18.9984, 127 I - 126.9045.
1) Calculate the ratio of the vibrational state populations n1/n0 for F2 at 310 K
2) Calculate the ratio of the vibrational state populations n1/n0 for F2 at 900 K
3) Calculate the ratio of the vibrational state populations n2/n0 for F2 at 310 K .
4) Calculate the ratio of the vibrational state populations n2/n0 for F2 at 900 K .
5) Calculate the ratio of the vibrational state populations n1/n0 for I2 at 310 K
6) Calculate the ratio of the vibrational state populations n1/n0 for I2 at 900 K
7) Calculate the ratio of the vibrational state populations n2/n0 for I2 at 310 K .
8) Calculate the ratio of the vibrational state populations n2/n0 for I2 at 900 K .
For F2,
reduced mass for F2 (u1) = [(18.9984)^2/(18.9984 + 18.9984)]/6.023 x 10^26 = 1.58 x 10^-26 kg
vibrational frequency for F2 (v1) = [1/2pi.sq.rt.(k/u1)]
k = 470 N.m-1
v1 = (1/2 x 3.14) x sq.rt.(470/1.58 x 10^-26) = 2.746 x 10^13 s-1
Population analysis
1) n1/no = e^-(hv1/Kb.T)
T = 310 K
Kb = Bolzman constant
h = planck's constant
n1/no = e^-(6.626 x 10^-34 x 2.746 x 10^13/1.38 x 10^-23 x 310) = 0.0142
2) at T = 900 K
n1/no = e^-(6.626 x 10^-34 x 2.746 x 10^13/1.38 x 10^-23 x 900) = 0.2311
3) at T = 310 K
n2/no = e^-(2 x 6.626 x 10^-34 x 2.746 x 10^13/1.38 x 10^-23 x 310) = 0.0002
4) at T = 900 K
n2/no = e^-(2 x 6.626 x 10^-34 x 2.746 x 10^13/1.38 x 10^-23 x 900) = 0.0534
For I2
reduced mass for I2 (u2) = [(126.9045)^2/(126.9045 + 126.9045)]/6.023 x 10^26 = 1.05 x 10^-25 kg
vibrational frequency for F2 (v1) = [1/2pi.sq.rt.(k/u1)]
k = 172 N.m-1
v1 = (1/2 x 3.14) x sq.rt.(172/1.05 x 10^-25) = 6.445 x 10^12 s-1
Population analysis
5) n1/no = e^-(hv1/Kb.T)
T = 310 K
Kb = Bolzman constant
h = planck's constant
n1/no = e^-(6.626 x 10^-34 x 6.445 x 10^12/1.38 x 10^-23 x 310) = 0.3685
6) at T = 900 K
n1/no = e^-(6.626 x 10^-34 x 6.445 x 10^12/1.38 x 10^-23 x 900) = 0.7090
7) at T = 310 K
n2/no = e^-(2 x 6.626 x 10^-34 x 6.445 x 10^12/1.38 x 10^-23 x 310) = 0.1358
8) at T = 900 K
n2/no = e^-(2 x 6.626 x 10^-34 x 6.445 x 10^12/1.38 x 10^-23 x 900) = 0.5027