The number of ways in which four molecules can be distributed in two different energy levels is : · ABC26PH0201
Subject: Physical Chemistry · Chapter: Statistical Thermodynamics · Topic: Statistical Thermodynamics – General · Exam: CSIR NET DEC 2013 · Marks: 2 · Difficulty: Medium
The number of ways in which four molecules can be distributed in two different energy levels is :
(a)6
(b)3
(c)16
(d)8
Answer
Answer (as printed): C
Explanation
16 The molecule with the smallest rotation partition function at any temperature among the following is : a) CH3—C ≡ C—H b) H—C ≡ C—H c) H—C ≡ C—D d) D—C ≡ C—D Since rotational partition function is given by Ír - Ï q= where, B= ÎÏÐS ef ; ÑÐ Ír - ef; Ñ:- Ñ q= • = =𝑞∝ ÎÏÐ ; ÎÏ ; Î ÒÓ ÔÕ Hence, two factor should be considered (i)I∝ 𝜇 (ii) 𝜎(symmetry number) In present case, H-C=C-H has smallest 𝜇 (reduced mass) also having σ= 2. Therefore, H- C=C-H will have smallest rotational partition function . CSIR JUNE 2014
Explanation as extracted from the printed page; notation may be imperfect.