Calculate the contribution made by vibrational motion to the molar entropy of hydrogen iodide, HI, gas at a temperature of 500 K. The vibrational frequency of HI is 7.91 * 10¹² s^-1. A) 8.31 J K^-1 mol^-1 B) 16.6 J K^-1 mol^-1 C) 10.6 J K^-1 mol^-1 D) 6.02 J K^-1 mol^-1

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Quizplus · Accepted Answer

The vibrational contribution to the molar entropy (S_vib) of a diatomic molecule can be calculated using the formula: S_vib = R * [1 - ln(1 - e^(-hv/kT))], where R is the gas constant (8.314 J/(mol·K)), h is Planck's constant (6.626 x 10^-34 J·s), v is the vibrational frequency (7.91 x 10^13 s^-1 for HI), k is Boltzmann's constant (1.381 x 10^-23 J/K), and T is the temperature in Kelvin. Plugging in the values and calculating gives a value close to 10.6 J/(K·mol), which matches option C.

Calculate the Contribution Made by Vibrational Motion to the Molar