2
O4was introduced and the pH of the resulting solution was adjusted to permit the quantitative precipitation of CaC2O4, the solid was isolated by filtration, washed free excess C2O42-,and dissolved in dilute H2SO4. Titration of the liberated H2C2O4, required 26.77mLof 0.02356 mol·L-1KMnO4. Calculation the mass fraction of CaO in the sample.
(已知CaO的摩尔质量58.06gmol1)
(1)需称取上述试样多少克?
(2)以浓度为0.0100mol·L-1的碱溶液代替1.000mol·L-1的碱溶液滴定,重复上述计算.
(3)通过上述(1)(2)计算结果,说明为什么在滴定分析中常采用的滴定剂浓度为0.1-0.2mol·L-1.
水硬度的单位是以CaO为基准物质确定的,10为1L水中含有()
A.1gCaO
B.0.1gCaO
C.0.01gCaO
D.0.001gCaO
25℃,,CO2饱和溶液的浓度为1.5×10-5mol·L-1,且假定溶于水中的CO2均生成了H2CO3试通过计算说明酸雨的pH应该小于多少?