【判断题】Sophie is a nurse. She is very busy.
【单选题】waht's wrong with sophie?
B.
she has a cold, keeps coughing all time
【多选题】采用二苯碳酰二肼分光光度法测定水中六价铬时,( )等对测定有干扰。
【简答题】采用二苯碳酰二肼分光光度法测定水中六价铬,当样品经锌盐沉淀分离法前处理后仍含有机物干扰时,应该如何处理?
【单选题】Miss Sophie was very surprised ________ hear the news.
【简答题】Tiffany, a 16-year-old girl, was very shy. Last September, her best friend, Sophie, moved abroad with her family because she had to continue her studies in America. She even said she would not come ba...
【单选题】关于二苯碳酰二肼分光光度法测定六价铬,下列说法正确的是( )
B.
在酸性溶液中,六价铬和三价铬能与二苯碳酰二肼反应生成紫红色化合物
【单选题】用二苯碳酰二肼分光光度法测定水中六价铬时,在水样采集至分析时应采用下列哪种方式
【单选题】采用二苯碳酰二肼分光光度法测定水中的六价铬,当水样浑浊、色度很深时,可以采用____对水样进行预处理。
【单选题】Miss Sophie was very surprised hear the news.