【单选题】China's first Mars probe,Yinghuo-1,is expected to be launched in the second half of this year and it will be the first time that China will __________ another planet. [ ]
【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
【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】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 ...