【单选题】在配位滴定中常用指示终点的指示剂是 ( )
【判断题】常用农业投入品可以在淘宝、京东、天猫等公共电商平台网购。( )
【单选题】1-4、以下叙述中正确的是______。
【单选题】常用铬黑 T 作指示剂的滴定分析是 ( )
【简答题】In many English homes, people eat four meals a day: breakfast, lunch, tea and dinner. People have breakfast from seven to nine in the morning. They eat porridge (粥) , eggs and bread. They also drink t...
【简答题】阅读短文,填入所缺单词: I have six silkworms. They are small and white. They have many ______. I put _______ on the leaves. They like _______ the leaves. They grow and grow. They ______ small, but now they are b...
【简答题】Sam and Ann have three meals a day: breakfast, lunch, 1 dinner. They have breakfast at home. 2 weekdays they have lunch at school. They 3 have quick meals such as hamburgers and hot dogs. 4 on weekend...
【单选题】在盐酸浓度标定实验中,已知Na2CO3浓度为0.1356g , 消耗HCl体积15.61 mL,计算HCl浓度为 ( ) mol/L