液态易挥发性试剂在实验应用中的污染防治

液态易挥发性试剂在用量筒量取和配制时，会因试剂强烈挥发而造成空气污染，使用滴管、移液管和带刻度烧杯等其他器皿甚至废旧空瓶替代就可大大减少试剂的挥发。     

量的名称及表示（2）

1．2 量符号 量符号书写与使用，需要注意以下几点：1．量符号必须使用斜体字母，矢量和张量还应使用黑斜体；仅有pH用正体。     

理科综合总复习指要

一、基础知识要夯实 理科综合测试卷最鲜明的特点就是基础性,基础知识是高考的首要依据,基础不扎实是考试失分的首要原因.理、化、生三科综合在一起知识面广,题量大,而答题的时间有限,所以三科综合考查必然是突出对基础知识的考查.具体说来就是--以考试大纲为依据,同时不拘泥于教材内容,要求同学们做到五个能:①能清楚地复述所学的基本概念、基本规律、基本原理和基本观点;②能对重点概念、原理和观点进行分解和综合;③能梳理教材的知识体系,揭示重点知识之间的内在联系;④能比较、分析同类型知识的差异;⑤能运用所学知识分析、解决实际问题.     

水合高碘酸镉盐溶解反应的热力学性质

用恒温热量计测定了 Cd2 HIO6 · 1 .2 5 H2 O在 3 mol· dm- 3HNO3水溶液中的标准摩尔溶解焓变 ,计算出了相应的标准摩尔自由能变与标准摩尔熵变 .用线性回归法分析并修正了用分光光度计在 2 98.5～ 3 2 8K范围内测定与计算的文献值     

有奖储蓄中奖号码的计算机分析

本文根据K.Pearson X~2的检验法,对中国工商银行浙江省分行1981年1月～1987年12月所有的由摇奖机摇出的有奖储蓄的中奖号码,利用电子计算机进行了统计分析.运算结果肯定了中国工商银行浙江省分行目前的摇奖方法是可靠的.也就是说,每个月在全省的某一地、市、县轮流用不同的摇奖机、不同的号珠,由不同的操作人员摇出中奖号码的方法,是行得通的.同时也指出,广大储户完全没有必要去择号购奖券,甚至买好以后再去调换所谓“中意的奖券,因为相对于信度10%而言,我们肯定了假设H:0～9这十个号珠中的每一个被摇奖机摇出的概率是相等的.”     

关于Runge－－Lenz矢量的方向和大小的讨论

描述行星规律的R-L矢量在笔者所见的文献中只指出了它的方向但末证明，本文对其加以了证明；并在此基础上比较简略地计算了它的大小；进而讨论了它的物理意义。     

Investigation of iodine concentration in salt,water and soil along the coast of Zhejiang,China

Objective: We aim to describe the environment iodine concentration in salt, water and soil along Zhejiang Province coast in the China foreland. It will be helpful for us to judge whether this area is insufficient in iodine and universal iodized salt is necessary or not. Methods: We collected iodized salt samples, drinking water samples (tap water in the towns, and well water or spring water in the villages), water samples from different sources (ditches, lakes, rivers) and soil samples through random sampling in June, 2005. Salt, water and soil iodine was detected by arsenic-cerium redox method. Statistical analysis was expressed as mean±SEMby Windows SPSS 13.0. Results: (1) The iodine concentration in salt was 27.9±4.33 mg/kg (n=108). (2) Seventy-five water samples were collected. The water iodine value was 0.6～84.8 μg/L (mean of 11.66 μg/L). The watershed along the Qiantang River has significantly higher iodine content than the water in Lin'an in mountain area (P＜0.01). The iodine content and mean iodine content of tap water, well or spring water and natural water sources were 4.30±2.43 μg/L (n=34), 23.59±27.74 μg/L (n=19)and 12.72±10.72 μg/L (n=22) respectively. This indicated that among environmental water sources, the ditch iodine content was the highest with river water iodine being the lowest (P＜0.01). (3) Soil iodine value was 0.11～2.93 mg/kg (mean of 1.32 mg/kg).Though there was no statistical difference of soil iodine in different districts (P=0.131), soil iodine content correlated positively with water iodine content. Conclusion: Iodine concentration in salt accords with national policy of adding iodine in salt. Foreland has more iodine in water than mountain area. The data reflected that water and soil iodine in foreland area was not high, which suggests universal iodized salt should be necessary. Environment iodine has relatively close association with pollution.     

解无数字计算题的几种方法

中学化学计算是学习化学的基础，学好化学计算有助于学生学好化学，提高科学探究的水平。考查化学计算能有效地考查学生的思维能力，无数据计算是培养学生创新能力，提高思维能力的较好题型。