㈠统揽全局,合理安排
在第一轮化学复习教学中必须纵观全局,注意各章节计算内容的合理渗透,循序渐进打好扎实的计算基础。各章节知识内容及方法见表2 。
知识内容 |
常见计算 |
常用解题方法 |
初中知识 |
溶质质量分数及溶解度 |
公式法、隔离法、终态分析法 |
化学反应及其能量变化 |
燃烧热、中和热的计算,氧化还原反应的有关计算 |
关系式法、电子转移守恒法 |
碱金属 |
有关Na,Na2O2,NaHCO3,Na2CO3的计算 |
差量法、极端分析法、不等式法、讨论法 |
物质的量 |
物质的量、质量、气体体积、微粒数、物质的量浓度、质量分数 |
公式法 |
卤素 |
卤素间的置换反应、过量问题计算 |
差量法、分段讨论法、数轴法、关系式法 |
物质结构元素周期律 |
相对原子质量、质量数质子数、中子数、电子数、最外层电子数电子层数、核电荷数、原子序数、周期数族序数、晶体结构 |
十字交叉法、公式法、占有比例法 |
硫硫酸 |
有关二氧化硫、硫酸在溶液中反应的计算 |
关系式法 |
碳族元素 |
碳硅及其化合物的计算 |
区间讨论法 |
氮族 |
氮及其化合物的计算、磷及其化合物的计算 |
讨论法、关系式法 |
几种重要的金属 |
金属与酸反应的计算、铝及其化合物的计算、无机混合物计算、铁及其化合物的计算 |
电子守恒法、元素组成守恒法、讨论法、图象法、图示分析法、关系式法、 |
有机化学 |
有机物燃烧的计算、有机混合物的计算 |
最间式法、通式法、差量法、不定方程讨论法、平均分子量法、平均组成法 |
化学反应速率化学平衡 |
化学反应速率的计算、有关化学平衡的计算 |
差量法、比例法、质量守恒法、等效转换法 |
电解质溶液 |
有关溶液混合后pH值及离子浓度的计算、电化学及氧化还原的计算 |
公式法、平衡计算法、电荷守恒法、原子守恒法、电子转移守恒法 |
㈡专题训练,提高效益
1、准确、熟练理解相关概念,形成和应用相关知识体系
掌握计算概念与化学原理是进行化学计算中思维活动的前提,也是化学计算的目的,化学计算的“化学味”就包括化学概念和原理。理解和运用计算概念、进行判断、推理,这是解题的思维过程。与计算相关的概念和公式又不是孤立的,它们之间存在着相互联系,只有将这些知识分类、交织成网,形成系统,才能完整、准确、灵活地掌握、运用它们,如果计算网络系统在头脑中排列有序,遇到问题便会产生有条有理的联想,再经过筛选、比较、判断、推理,就可以形成脉胳通畅的思路。可见,计算概念的准确理解和应用,不仅是化学计算的内容,而且是促使知识向能力转化,形成技能技巧、发展思维能力的重要因素。与计算相关的知识体系见下图。
近几年高考化学计算题的变化是难度有所降低,更加突出了化学计算的特点,与生产、科学研究的实际比较贴近。。根据历届高考试题中的考点显示,化学计算的考查主要包括元素的质量分数、分子式与相对原子质量和相对分子质量、溶解度、质量分数、物质的量浓度、溶液的pH值、有关化学平衡、多步反应、有关混合物、根据化学方程式计算及综合计算等十一个方面的计算。近几年的化学高考题对计算的技巧和方法(差量法、十字交叉法、估算法、等效转换法、守恒法、讨论法、极端假设法等)的考查要求有所降低,对思维逻辑性、敏捷性、发散性和创造性以及相关学科知识的运用能力有深刻的考查。
第二节:完形填空(共20小题;每小题1.5分,满分30分)
To be a good teacher, you need some of the gifts of a good actor; you must be able to hold the attention and interest of your students, you must be 36 -speaking, with a good, strong, 37 voice which is fully under your control; and you must be able to 38 what you are teaching, in order to make its meaning clear.
39 a good teacher and you will see that he does not sit still before his class; he 40 the whole time he is teaching; he walks about, using his 41 , hands and fingers to help him in his explanations, and his face to express his 42 . Listen to him, and you will 43 the loudness, the quality and the musical note of his voice always 44 according to what he is talking about. The fact that a good teacher has some of the gifts of a good actor doesn’t 45 that he will indeed be able to act well on the stage, for there are very important 46 between the teacher’s work and the actor’s. The 47 has to speak out words which he has learnt by heart; he has to repeat exactly the 48 words each time he plays a certain part, even his movements and the ways in which he uses his voice are usually 49 beforehand. What he has to do is to make all these carefully learnt words and actions seem 50 on the stage.
A good teacher 51 in quite a different way. His students take an active part in his 52 : they ask and answer questions, they obey orders, and if they don’t 53 something, they will say no. The teacher therefore has to suit his act to the needs of his students, which is in his class. He cannot learn his part by heart, but must 54 it as he goes along.
I have known many teachers who were fine 55 in class but unable to take part in a stage play because their brains wouldn’t keep discipline: they could not keep strictly to what another had written.
36. A. clear B. slow C. small D. low
37. A. frightening B. fearing C. exciting D. pleasing
38. A act out B. talk about C. say out D. speak out
39. A. Listen B. Look C. Watch D. Learn
40. A. stands B. sits C. lies D. talks
41. A. tongue B. words C. legs D. arms
42. A. attention B. thanks C. feelings D. sentences
43. A. hear B. see C. think D. guess
44. A. making B. changing C. expressing D. giving
45. A. tell B. express C. show D. mean
46. A. things B. differences C. points D. jobs
47. A. actor B. teacher C. boy D. student
48. A. different B. same C. above D. following
49. A. read B. known C. fixed D. written
50. A. natural B. bad C. false D. clear
51. A. is B. works C. has D. teaches
52. A. group B. party C. class D. play
53. A. give B. place C. obey D. hear
54. A. invent B. discover C. teach D. continue
55. A. learners B. watchers C. actors D. listeners
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