【简答题】已知25℃时下列弱酸的解离常数: HOCl的Kaθ=3.5×10-8,H3BO3的Kaθ=5.8×10-10,CH3COOH的Kaθ=1.8×10-5 (1)配置PH=4的缓冲溶液,用哪种酸最好? (2)需要多少克这种酸和多少克氢氧化钠配制1.0 L的缓冲溶液,其中这种酸和它的共轭碱的总浓度等于1.0 mol.dm-3。
【简答题】3) 评定车用汽油的 辛烷值 可采用两种试验工况,分别称为 辛烷值 与 辛烷值 。
【简答题】2 Complete the words. (You will answer the
questions in Exercise 3.) ► Do you live near a w o o d? wood ( Yes, I do. It’s 200 metres from my home. ) 1 Do you live in a v _ ll _ y or on a h _...
【单选题】— you sing the song Where Are You Going, Daddy? — Yes. It’s easy.
【单选题】—_____ —Yes, please. I want a notebook. [ ]
【单选题】听力原文:M: Are you really going to buy that painting? Where will you hang it? W: Yes, I think it would brighten my living room wall. Don't you love the way the blues and greens blend? Q: Where does the w...
【单选题】A: Could you tell me where you were studying at that time? B: ( ).
C.
enjoyed the game very much.
D.
was studying at the University of Sydney