第二节书面表达【写作思路】根据试题要求,考生需要写一篇记叙文,记述身边一位值得尊敬和爱戴的人。首先考生需要介绍自己最尊敬和爱戴的人是谁,简单地介绍一下他(她)。然后,陈述为什么他(她)值得尊敬和爱戴。最后,可以对前文进行一个总结,使文章结构严谨。本文的写作重点在"尊敬和爱戴的原因",考生可围绕这个要点适当拓展,从性格特点、处事风格等方面展开写作。【范文赏读】The most beloved and respected person around me is my teacher, Ms LiThough she has been teaching English for twenty years, she is still passionateabout teaching. She is kind and considerate towards us just like our dear motherWe all respect her because she always tries new ways to make her classes livelyand interesting. Hardworking and knowledgeable, she is one of the best teachersin our school. When we have a problem, we will turn to her for help. She alwaystalks to us patiently and helps us to find a solution. In our eyes, she is not onlyour teacher, but also our best friend. Those are why she deserves our respect【亮点词句】亮点词汇: beloved, respected, be passionate about, be consideratetowards, turn to sb. for help, in one's eyes亮点句式:Why引导的表语从句( why she deserves our respect)

18(1)NH HCO3(1 /) c(NH4 )>c(HCOF)>c(OH)>c(H)(1分)(2)1.3×10-3(2分)c(HCO3)(1分)2c(H2CO3)(1分)(3)H:O+ H3 PO3+ 2Ag-2Ag+ H3,+ 2H(1分)c(Na)=c(H2PO)+2c(HPO了-)(1分)0.0094(2分)(4)③>①>②>④(1分)【解析】(1)等物质的量的H2CO3和NH3·H2O反应生成酸式盐NH4HCO3。因为Kb(NH3·H:0)>Ka(H2CO3),HCO3的水解程度比NH大,水解均较微弱,故c(NH)>c(HCO3)>c(OH)>c(H”)。(2)常温下,该反应的平衡常数Kc(H:CO3)·c(NH3·H2())c(NH4)·c(HCO3)c(H2CO3)·c(NH3·H2O)·c(H+)·c(OHc(NH)·c(HCO3)·c(H+)·c(OH-)KKa(H2CO3)·K(NH3·H2O)1.3×10-3。根据题意,生成等物质的量的Na2CO3和(NH4)2CO3,由质子守恒得c(OH-)+c(NH3·H2O)=c(H+)+c(HCO3)+2c(H2CO)3),也可由物料守恒和电荷守恒得出该结论。(3)根据题意,可得离子方程式为H2O+H3PO3+2Ag+—2Ag+H3PO4+2H;溶液呈中性c(H+)=c(OH-),根据电荷守恒c(Na)=c(H2PO3)+2c(HPO-);一级电离平衡常数Kac(H2PO3)×c(H+)c(HPO),酸溶液中c(H2PO)≈c(H”)=3.9×10-2mol·L-,c(H3PO3)=0.2mol·L-1-3.9H2PO3)×c(H)10-2mol·L-,Ka≈0.0094C(H:PO)(4)四种溶液中,亚铁离子水解呈酸性,抑制铵根离子水解,碳酸根离子水解呈碱性,促进铵根离子水解,但毕竟水解程度一般很小所以这四种溶液中铵根离子浓度大小顺序是③>①>②>④。

以上就是2018-20英语周报答案八年级上册，更多英语周报答案请关注本网站。

本文地址： http://www.ncneedu.cn/post/4349.html

文章来源：admin

版权声明：除非特别标注，否则均为本站原创文章，转载时请以链接形式注明文章出处。