英语周报外研母版2020－2021第丨8期答案

16.(1)MnO2+4HC(浓MnCl2+Cl2↑+2H2O(3分)(2)饱和NaCl溶液(2分)(3)C装置液面上方有黄绿色气体(2分)(4)使反应生成的NaOH再次生成 NacIo并参与反应,提高原料利用率(2分)(5)冰水洗涤(2分)(6)64.5%(3分)解析:(1)根据装置图分析可知装置A用于制备氯气,因此对应的化学方程式为MnO2+4HC1(浓)=MnCl2+Cl2↑+2H2O1(2)氯气中混有氯化,也能和氩氧化钠反应,故装工B用于除去氯气中的氯化气体,所以装置B内盛装的试剂为饱和NaCl溶液;(3)装置C中为氯气和氢氧化钠溶液反应,因此裳置C内制各 NaCIo溶液完成的现象是C装置液面上方有黄绿色气体;(4)根据制备原理可知反应过程中会生成氩氧化钠,继续通入氯气会和氢氧化钠溶液反应产生次氯酸钠,即反应过程中仍需不断通入气体的原因是使反应生成的NaOH再次生成NaCO并参与反应,提高原料利用率;(5)由于二氧异氰尿酸钠(NaC2N3O3Cl2)难溶于冷水,所以反应结東后,C中浊液经过滤、冰水洗涤、干燥得粗产品二氯异氰尿酸钠:(6)根据题目信息可得HCO~2Na2S2O3,因此100mL溶液中HCO的物质的量为×(0.1000mol/L×20.00×10-3L)100mL10mL0.01mol,根据样品的有效氯测定中种化为HCO的氯元素质量2×100%的质0.01mol×2×35.5g/mol1.1000g100%=64.5%

书面表达One possible versionDear PeterI'm writing to invite you to see the Chinese Painting Exhibition to be held in our city.The exhibition will start at 8: 30 am on Saturday and last till 5: 00 pm on Sunday in the city museum It'ssaid that a large number of Chinese paintings, some of which are original works by famous painters like ZhangDaqian and Qi Baishi, will be on display. Besides, there will be various souvenirs to be sold. I know you re veryinterested in traditional Chinese culture, so I can t wait to tell you the news and hope we can go together.Looking forward to your reply.You

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