【简答题】听短文,根据所听内容选择最佳答案。短文读两遍。 1. Who was Mr Green? [ ] A. The new head. B. The new teacher. C. The new student. 2. Why did Mr Green go around the school? [ ] A. To enjoy the quiet school. B. T...
【简答题】听对话,回答问题。 1. When did the girl come back home? A. On Saturday. B. On Friday. C. On Wednesday. 2. What's the dialogue mainly about? A. The girl's vacation. B. The girl's parents. C. The girl's interest...
【简答题】今有0.10mol·L -1 甲酸与等浓度的氯化铵的混合液。选择哪种指示剂?(HCOOH的K a =1.8×10 -4 ,NH 3 的K b =1.8×10 -5 )
【单选题】10mol/L NH 2 OH 和 0.20mol/L NH 4 + 混合溶液的pH为( ) 已知羟胺 NH 2 OH K b = 9.1 × 10 -9 , NH 3 的 K b = 1.8 × 10 -5
【多选题】严禁利用网络( )他人及传播不健康的文字图片信息。
【单选题】NH 3 的 K b =1.8×10 -5 ,0.1mol/L NH 3 溶液的 pH 为( )。
【单选题】The boy liked ______ very much.
A.
his family living by the sea
B.
walking to his uncle's house every day
D.
staying in the sea and fishing
【单选题】已知NH 3 的K b =1.8×10 -5 ;则NH 4 + 的Ka是: ( )
【单选题】As a little boy, there was nothing I liked better than Sunday afternoons on my grandfather’s farm. 1 by miles of winding stonewalls, the house and barn provided endless hours of 2 for a city kid like ...