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中考化学试题分类汇编化学计算

中考化学 中考化学计算题 中考化学试题分类汇编
中考化学试题分类汇编化学计算

  出国留学网为大家提供《中考化学试题分类汇编化学计算》,希望对大家的中考有帮助!

  点击下载:中考化学试题分类汇编化学计算

  相关链接:中考化学计算题有哪些解题技巧

  中考一般是2道计算。第1个应该是溶液的计算。书上的那几种方法好好看看,计算别错了,应该没问题。第2个是方程式的题。方程式写对,条件、0符号别忘了,2分得到了,然后把给的那几个数带入方程式,就行了。

  重要概念的含义与应用:化学计算是借助于用数学计算的知识,从量的方面来对化学的概念或原理加深理解或通过计算进一步掌握物质的性质及其变化规律。另外,通过计算还能培养分析、推理、归纳等逻辑思维能力和解决实际问题的能力。

  初中化学计算的主要内容如下:

  (一)有关化学式的计算

  用元素符合来表示物质组成的式子叫做化学式。本知识块的计算关键是抓住这一概念,理解概念的含义,并要深刻理解化学式中各符号及数字的意义,处理好部分与整体之间的算术关系。

  1.计算相对分子质量。

  相对分子质量是指化学式中各原子的相对原子质量的总和。通过化学式可以计算出该物质的相对分子质量,也可以通过相对分子质量,求某物质的化学式。在计

  算的过程中应注意化学式前面的数字(系数)与相对分子质量及元素符号右下角的数字与相对原子质量之间的关系是“相乘”不是“相加”;若计算结晶水合物的相

  对分子质量时,化学式中间的“·”与结晶水的相对分子质量之间是“相加”不是“相乘”。

  例计算5CuSO4·5H2O的相对分子质量总和

  5CuSO4·5H2O=5×[64+32+16×4+5×(1×2+16)]=5×[160+5×18]=1250

  2.计算化合物中各元素的质量比

  宏观上物质是由元素组成的,任何纯净的化合物都有固定的组成,这样可以计算化合物中所含元素的质量比。计算的依据是所含元素的质量比,等于微观上每个分子(即化学式)中各种原子的个数与其原子量的乘积之比。

  例计算氧化铁中铁元素和氧元素的质量比。

  氧化物的化学式:Fe2O3,则

  Fe∶O=56×2∶16×3=112∶48=7∶3

  3.计算化合物中某元素的质量分数

  宏观上化合物中某元素的质量分数等于微观上化合物的每个分子中,该元素的原子的相对原子质量总和与化合物的相对分子质量之比,即:化合物中某元素质量比=×100%

  例计算硝酸铵(NH4NO3)中,含氮元素的质量分数。

  w...

与高考化学真题分类汇编相关的中考化学

高考语文易错成语汇编:褒贬不分类

高考语文 易错成语 高考语文易错成语

  出国留学网整理了高考语文易错成语汇编:褒贬不分类,以供考生们参考,更多资讯请关注本网站更新。

  高考语文易错成语汇编:褒贬不分类

  1.拭目以待:形容期望很迫切。

  2.神机妙算:形容预料准确,善于估计形势,决定策略。

  3.名不虚传:指实在很好,不是空有虚名。

  4.凤毛麟角:比喻珍贵而稀少的人或事物。

  5.洋洋大观:形容美好的事物众多丰盛。

  6.沁人心脾:形容诗歌和文章优美动人,给人清闲爽朗的感觉。

  7.别有天地:形容风景或艺术创作的境界引人入胜。

  8.别出心杼:比喻写作不因袭前人,另辟新路。

  9.有口无心:指不是有心说的。

  10.惨淡经营:指苦心费力经营。

  11.来日方长:未来的日子还很长。表示事有可为,劝人不必急于做某事。

  推荐阅读:

  高考语文易错成语汇编:望文生义类

  高考语文易错成语汇编:对象误用类

与高考化学真题分类汇编相关的高考语文

中考英语复习:2009年中考英语真题分类汇编 阅读理解(4)

德州市 前缀 安眠药
《2009年中考英语真题分类汇编 阅读理解(4)》由留学英语组编辑整理(m.liuxue86.com)。本内容整理时间为05月12日,如有任何问题请联系我们。

2009年中考英语真题分类汇编:阅读理解(4)

(十六)(2009德州市)

Mark was walking home from school one day when he noticed a boy ahead of him. He had tripped (绊倒) and dropped all of the books he was carrying, along with some clothes, a baseball bat and a glove.

Mark knelt (跪) down and helped the boy pick up the things. Since they were going the same way, he offered to carry some things for the boy.

As they walked, Mark discovered the boy's name was Bill. He loved video games, baseball and history, but he was having trouble with some of his subjects.

They arrived at Bill's home first. Mark was invited in for a Coke and to watch some television. The afternoon passed pleasantly with some laughs and talk. Then Mark went home.

They continued to see each other around school, had lunch together once or twice, then both graduated from junior school.

Three days before graduation, Bill asked Mark if they could talk.

Bill reminded (提醒) Mark of the day years ago when they had first met. "Did you ever wonder why I was carrying so many things home that day?" asked Bill.

"You see, I took away all my things from school. I had stored away some of my mother's sleeping pills (安眠药). I was going home to kill myself. But after we spent some time talking and laughing, I realized that if I had died, I would have missed so many good times. So you see, Mark, when you p...

中考英语复习:2009年中考英语真题分类汇编 完形填空(5)

东营 前缀 山东
《2009年中考英语真题分类汇编 完形填空(5)》由出国留学编辑精心为您学习英语准备.liuxue86.com。本内容整理时间为05月12日,如有任何问题请联系我们。

2009年中考英语真题分类汇编:完形填空(5)

(二十一)(2009山东东营)

All over the world people swim for fun. Swimming is enjoyed by people of 1 ages, from the very young to the very old. There are many places for people to swim in swimming pools. Many schools, hotels and clubs have swimming pools. Some people have pools of 2 in their yards.

Swimming is one of 3 forms of exercise. It can 4 hearts and bodies strong. It can also help blood circulate(循环). Handicapped people can keep their bodies in better condition by swimming 5 they can't enjoy sports.

6 is a good idea for parents to see to it(务必做到) that their children learn to swim 7 an early age. So their children will 8 it for the rest of their lives.

There are many rules for water safety. These rules can help save not only your life 9 the life of a friend. First of all, know 10 . Many schools 11 swimming lessons to children. Adults(成人) can learn to swim at public pools. 12 rule to remember is never to swim 13 . Always swim with a friend and know 14 in the water at all times. It is best to swim 15 in safe places if you are beginners. If every one learned to swim and obeyed the rules for water safety, most drawing(溺水) could be avoided.

1. A.all B. any C. someD. both

2.A.themselves B.their own C. theirs ownD. their own's

3.A.good B. better C. bestD. the best

4.A.help B. let C. makeD. show

<...

中考英语复习:2009年中考英语真题分类汇编之--阅读理解

英语 前缀 时间
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2009年中考英语真题分类汇编:阅读理解

2009年中考英语真题分类汇编:阅读理解(1)

2009年中考英语真题分类汇编:阅读理解(2)

2009年中考英语真题分类汇编:阅读理解(3)

2009年中考英语真题分类汇编:阅读理解(4)

2009年中考英语真题分类汇编:阅读理解(5)

2009年中考英语真题分类汇编:阅读理解(6)

《2009年中考英语真题分类汇编之--阅读理解》由留学liuxue86.com编辑整理

中考英语复习:2009年中考英语真题分类汇编 完形填空(1)

空格 答案 前缀
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2009年中考英语真题分类汇编:完形填空(1)

(一)(2009广州)VII.完形填空(共10个空格,每个空格1分)

先通读下面短文,掌握大意,然后从下面四个答案中选择可以填入相应空白处的最佳答案

Peter and Paul passed by a small house on their way home late at night. They saw thick 64 coming out of its windows. "It's on fire!" said Peter. "We must get help. "

The two brothers ran 65 the road shouting "Fire! Fire! "They 66 on the door of the next house. They asked them to 67 the police and the firemen.

They ran back to the house. They saw 68 the window an old lady sitting in an arm-chair. It was 69 that she could not move. Peter and Paul tried hard to carry her out of the 70 and so they did! Some neighbours (邻居) came and helped take some things out.

In no time the firemen 71 as well as the policemen. The fire was put out. The old lady cried sadly 72 she was not hurt. She thanked Peter and Paul and her neighbours 73 .

64. A. snow B. clouds C. fire D. smoke

65. A. over B. along C. at D. with

66. A. knocked B. beat C. locked D. opened

67. A. tell B. report C. telephone D. find

68. A. at B. through C. above D. on

69. A. old B. difficult C. free D. clear

70. A. arm-chair B. window C. house D. road

71. A. arrived B. fought C. left D. returned

72. A. so B. for C. and D. but

73. A. up and down B. again and again C. hour after hour D. from side to side

【答案】64. D 65. B...

中考英语复习:2009年中考英语真题分类汇编 阅读理解(5)

通化 内容 问题
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2009年中考英语真题分类汇编:阅读理解(5)

(二十一)(2009吉林通化)

It was December 25. Marie, a 13-year-old Australian girl, was happy. It was Christmas, and Marie' s mother was making a special cake. She put four small coins into the cake, and then she baked (烤) it. The four coins were for good luck. After dinner Marie and her family ate the cake. They found three coins in the cake and put them on the table. Where was the fourth coin? It was missing, but Marie's mother didn't notice.

After Christmas Marie got sick. She coughed, and she couldn' t speak. After six weeks she felt better, but she still couldn't speak. Marie's parents took her to hospital. Doctors at the hospital looked her over, and then said, "We are sorry, but we can't help her. "For 12 years Marie didn't speak. She grew up, she got a job, and she got married. But she never spoke. One day, when Marie was 25 years old, she got a sore throat ( 嗓子疼 ) at work. She began to cough. She coughed up something small and black. What was it? Marie didn't know. She took it to the hospital. A doctor at the hospital said, "This is a coin!" The doctor told Marie, "I think you can speak again. " Marie went to a special doctor, and soon she could talk.

根据短文内容,回答问题。

1. What did Marie's mother make on Christmas?

__________________________________________________________

2. What did Marie's mothe...

中考英语复习:2009年中考英语真题分类汇编 阅读理解(2)

前缀 江西 英语
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2009年中考英语真题分类汇编:阅读理解(2)

(六)(2009江西)

【答案】73-76 DAAD

......

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