【简答题】在pH=5.0的HAc—Ac-缓冲溶液中,以0.02000mol/L EDTA滴定同浓度的Pb2+,已知终点时,游离Ac-浓度为0.1mol/L,以二甲酚橙(XO)为指示剂,终点时pPb为__________,pYep为__________。(1gKPbY=18.0;pH=5.0时,lgαY(H)=6.5;pPbep(XO)=7.0;Pb2+Ac-配合物的lgβ1一1gβ2为2.0、3.3)
【简答题】以0.020mol·L -1 EDTA滴定浓度均为0.020mol·L -1 Pb 2+ 和Ca 2+ 混合溶液中的Pb 2+ ,终点时pH=5.0的HAc-Ac - 缓冲溶液,c(Ac - )为0.1mol·L -1 。若以二甲酚橙为指示剂,计算化学计量点时的pPb' sp 、p CaY 和终点误差。(lgK PbY =18.04,lgK CaY =10.7;pH=5.0时,lgα Y(H) =...
【单选题】Tom, turn down the music. Why _____ you make such a big noise while your baby sister is sleeping? [ ]
【单选题】—Tom, why don't you do your homework in your room? —I _____it already. [ ]
【单选题】Why does Jane refuse Tom's invitation?
A.
Because she wants to study for a test.
B.
Because she wants to go swimming at the student center.
C.
Because she has to do research in the library.
D.
Because she is not interested in the man.
【判断题】25℃时,0.1mol.L-1HAc的α= 1.33%,表示在该溶液中每10000个HAc分子有约133个 HAc分子解离成H+ 和Ac-
【单选题】Why,Tom, didn't you get your bike ? [ ]
【单选题】在 50mL0.1 mol ·L -1 HAc溶液中加入等体积水稀释,对稀释后的水溶液而言,下列叙述正确的是 A B C D
A.
HAc 的解离度 α 减小,溶液的 pH 值减小
B.
HAc 的解离度 α 增大,溶液的 pH 值增大
C.
HAc 的解离度 α 增大,溶液的 pH 值减小
D.
HAc 的解离度 α 增大, HAc 的解离常数增大
【单选题】1mol·L -1 HAc,α HAc =1.33%,则在此溶液中微粒浓度最大的是
【单选题】1mol/lHAc 溶液中 HAc 的 α = 1.33%, 则 [H+] 为( ) mol/l.