A.He dresses in an informal manner at work. B.He dresses very casually on vacatio
A. He dresses in an informal manner at work.
B. He dresses very casually on vacation.
C. He gets unfamiliar in the eyes of his friends.
D. He is a lousy employee at work.
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有一样品含甲酸、乙酸、丙酸及少量水、苯等物质,称取样品1.055g,以环己酮作内标,称取0.1907g环己酮加到样品中,混合均匀后进样,得如下数据
求甲酸、乙酸和丙酸的质量分数。
某一色谱柱从理论上计算得到的理论塔板数n很大,塔板高度H很小,但实际上柱效并不高,试分析原因。
某人制备了一根填充柱,用组分A和B为测试样品,测得该柱理论塔板数为4500,因而推断A和B在该柱上一定能得到很