[Soda Ash Knowledge] Question of the Day (15) October 18, 2009
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Please hide replies; otherwise, no scoring will be given in principle. Specific hiding method: http://bbs.hcbbs.com/viewthread.php?tid=492556&highlight=%D2%FE%B2%D8 Edited posts are not rated. (The topic of this issue is taken from page 63 of “Question Bank for On-the-Job Training of Skilled Workers – Operators in Soda Ash Production”. The electronic version of this book can be downloaded from the Soda Ash Information Sharing Section: http://bbs.hcbbs.com/thread-13140-1-2.html.) True or False: 1. In the crystallizer, AI causes ammonium chloride to crystallize through cooling and the salting-out effect resulting from the addition of NaCl. ( ) 2. The supersaturation of a solution is generally expressed in terms of temperature supersaturation or concentration supersaturation. ( ) 3. Both sodium bicarbonate crystallization and ammonium chloride crystallization occur due to the formation of supersaturation caused by temperature changes. ( ) 4. Within a certain degree of supersaturation, vibration or the addition of seeds can both induce crystallization. ( ) 5. Regions with high supersaturation can be divided into a metastable region and an unstable region. ( )
1. Right 2. Right 3. Wrong 4. Right 5. Right
1. In the crystallizer, AI causes ammonium chloride to crystallize through a cooling effect and the salting-out effect resulting from the addition of NaCl. (T) 2. The supersaturation of a solution is generally expressed in terms of temperature supersaturation or concentration supersaturation. (T) 3. Both sodium bicarbonate crystallization and ammonium chloride crystallization are caused by temperature changes that lead to supersaturation. (F) 4. Within a certain degree of supersaturation, vibrations or the addition of seeds can both induce crystallization. (T) 5. The regions with high supersaturation can be divided into a metastable region and an unstable region. (T)
1. In the crystallizer, AI causes ammonium chloride to crystallize through a cooling effect and the salting-out effect resulting from the addition of NaCl. (Correct) 2. The supersaturation of a solution is generally expressed in terms of temperature supersaturation or concentration supersaturation. (Correct) 3. Both sodium bicarbonate crystallization and ammonium chloride crystallization are caused by temperature changes that lead to supersaturation. (Incorrect) 4. Within a certain range of supersaturation, vibrations or the addition of seeds can both induce crystallization. (Correct) 5. Regions with high supersaturation can be divided into a metastable region and an unstable region. (Yes)