【简答题】以0.020 mol.dm-3EDTA滴定浓度均为0.020 mol.dm-3Pb2+和Ca2+混合溶液中的pb2+,终点时pH=5.0的HAc—Ac-缓冲溶液,c(Ac-)为0.1 mol.dm-3。若以二甲酚橙为指示剂,计算化学计量点时的pPbsp’,pCaY和终点误差。(lgfθ(PbY)=18.04,lg(CaY)=10.7,pH=5.0时,lgα(Y(H))=6.45,Pbep(XO)=...
【单选题】相对标准偏差属于药物分析方法效能指标( )
【单选题】---Would you mind if I turned on the radio and listened to some music? --- __________. In fact, I also like to listen to music in my car.
【判断题】货币发行是当今世界各国中央银行享有的垄断权力。( )
【单选题】Copyright of music may harm the majority of performers in that it
A.
in fact protects a few celebrities.
B.
covers the creations of most people.
C.
forbids the rich as well as the poor.
D.
doesn't allow the mass to steal music.
【简答题】向NH 3 和NH 4 Cl的浓度均为0.20mol·L -1 缓冲溶液中加入等体积的0.020mol·L -1 [Cu(NH 3 ) 4 ]Cl 2 溶液,是否有Cu(OH) 2 沉淀生成?已知:K b (NH 3 ·H 2 O)=1.8×10 -5 。K s ([Cu(NH 3 ) 4 ] 2+ )=2.1×10 13 ,K sp (Cu(OH) 2 )=2.2×10 -20
【单选题】—Would you mind if I turned on the radio and listened to some music? —_________. In fact, I also like listening to music.
【多选题】乙公司是一家酒店连锁企业。该公司在构建战略控制系统时,应考虑( )
【简答题】Everyone enjoys music. But do you know it can improve the lives of sick kids? __57___ In fact, music has changed the world a lot. In Australia , a scientist, Catherine, has made a music program. ___5...