2022英语周报宜昌42期答案

27.(1):O::C∴:O:(2分)(2)NH3(2分)(3)CO2NH3(各1分)(4)NH4CNH3↑+HCl↑(2分)(5)①MgCl2+2H20=Mg(OH)2￥+2HCl↑(2分)Mg(OH)2=MgO+H2O(2分)②能防止NH3和HCl因接触而反应生成氯化铵(2解析:(1)碳酸氢钠分解生成碳酸钠、水和二氧化碳气体则X为二氧化碳,电子式为:O:C:O:;(2)由于二氧化碳在水中溶解度较小,而氨气在水中溶解度很大,所以为了尽可能生成 NaHCO3,应该尽可能增大二氧化碳溶解度,而先通入氨气使溶液显碱性,可提高二氧化碳溶解度(3)根据流程图,反应Ⅱ中生成的二氧化碳和反应Ⅲ生成的氨气可以参与反应I,据此判断参与循环使用的气体有CO2、NH3(4)所得产品Na2CO中不会含有NH4Cl,因为氯化铵受热容易分解NH4Cl-NH3+HCl;(5)①步骤ⅱ实际上要经过加热和高温两步反应,“加热步骤中促进氯化镁水解制得HCl.“高温”步骤使得氢氧化镁分解得到MgO,化学方程式分别为MgCl2+2H2Oy1)2y+2HCl↑,Mg(OH24MgO+H, O:②过程Ⅲ分两步得到NH3和HCl,可以防止NH3和HCl反应生成氯化铵,比一步得到NH3和HCl要好

Possible version:Tom thought for a moment and was about to agree, but he changed his mind. " I can't, BenYou know Aunt Polly wants the fence to be perfect. It has to be done very carefully.I don'tthink you can do it well enough. "He said to Ben, who looked a little discouraged. "Oh, Tom, I'llbe careful. Please let me have a try I would like to give you my apple if you agree, "requestedBen In the end, Tom gave up the brush with unwillingness on his face, but joy in his heartWhile ben worked at the fence in the hot sun Tom sat under a tree, eating the apple, andlanning how to get more help. many of his other friends walked past him. Each one came topllaugh, but remained to whitewash the fence because they all got interested in it. One by one, theywhitewashed the fence, each giving Tom a reward, big or small. If he hadn't run out ofwhitewash, Tom would have owned everything belonging to his friends. He had a most wonderful andidle Saturday, sitting in the shade and enjoying the rewards that his friends gave him

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