Concept explainers
(a)
Interpretation:
The expected ratios of molecules in odd rotational states to even rotational stated for given molecule is to be predicted.
Concept introduction:
The antisymmetric spin states represent the even rotational states while symmetric spin states represent the odd rotational states.
The odd rotational states are calculated by,
The even rotational states are calculated by,
Where,
•
(b)
Interpretation:
The expected ratios of molecules in odd rotational states to even rotational stated for given molecule is to be predicted.
Concept introduction:
The antisymmetric spin states represent the even rotational states while symmetric spin states represent the odd rotational states.
The odd rotational states are calculated by,
The even rotational states are calculated by,
Where,
•
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Physical Chemistry
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- The rotational constant for CO is 1.9314 cm−1 and 1.6116 cm−1 in the ground and first excited vibrational states, respectively. By how much does the internuclear distance change as a result of this transition?arrow_forwardCalculate the relative populations of the J = 2 and J = 1 rotational levels of HCI at 25 oC. For HCI the rotational constant is B =318.0 GHz.arrow_forward5. For carbon monoxide at 298K, determine the fraction of molecules in the rotational levels for J=0, 5, 10, 15, and 20. The rotational constant (B) is 3.83x10^-23 Joules.arrow_forward
- Estimate the rotational partition function of ethene at 25 °C given that ᷉ A = 4.828 cm−1, ᷉ B =1.0012 cm−1, and ᷉ C = 0.8282 cm−1. Take the symmetry number into account.arrow_forwardCalculate the standard molar entropy of N2(g) at 298 K from its rotational constant ᷉ B = 1.9987 cm−1 and its vibrational wavenumber ᷉v = 2358 cm−1. The thermochemical value is 192.1 J K−1 mol−1. What does this suggest about the solid at T = 0?arrow_forwardThe vibrational wavenumber of Br2 is 323.2 cm−1. Evaluate the vibrational partition function explicitly (without approximation) and plot its value as a function of temperature. At what temperature is the value within 5 per cent of the value calculated from eqn 13B.16, which is valid at high temperatures?arrow_forward
- Calculate the relative numbers of Br2 molecules ( ᷉v = 321 cm−1) in the second and first excited vibrational states at (i) 298 K, (ii) 800 K.arrow_forwardEstimate the values of γ = Cp,m/CV,m for gaseous ammonia and methane. Do this calculation with and without the vibrational contribution to the energy. Which is closer to the experimental value at 25 °C? Hint: Note that Cp,m − CV,m = R for a perfect gas.arrow_forwardEvaluate the rotational partition function of pyridine, C5H5N, at 25 °C given that ᷉ A = 0.2014 cm−1, ᷉ B = 0.1936 cm−1, ᷉ C = 0.0987 cm−1. Take the symmetry number into account.arrow_forward
- Physical ChemistryChemistryISBN:9781133958437Author:Ball, David W. (david Warren), BAER, TomasPublisher:Wadsworth Cengage Learning,