用電位滴定法測定鐵精礦中鐵的質(zhì)量分?jǐn)?shù)(%),6次測定結(jié)果如下:
60.72 60.81 60.70 60.78 60.56 60.84
(1) 用格魯布斯法檢驗有無應(yīng)舍去的測定值(P=0.95);
(2) 已知此標(biāo)準(zhǔn)試樣中鐵的真實含量為60.75%,問上述測定方法是否準(zhǔn)確可靠(P=0.95)?
根據(jù)有效數(shù)字的運算規(guī)則進(jìn)行計算:
(1)7.9936÷0.9967-5.02=?
(2)0.0325×5.103×60.06 ÷139.8=?
(3)(1.276×4.17)+1.7×10-4-(0.0021764×0.0121)=?
(4)pH=1.05,[H+]=?