2022-2022高一课标英语周报答案

第二节【参考范文】On that Sunday, I paid a visit to Willard's family. On entering his house, I was surprised to find a barelyempty room with a broken bed and a dirty sofa. It seemed as if the house had been unoccupied for a longtime. willard told me his mother died and that his father was missing when he was five, leaving him to livewith a sick grandma. When asked why he had given the two quarters, Willard mumbled, "I just want to helpothers by contributing my milk money. I couldn t help bursting into tears. thinking I should help him breakhis silence. On my way home, I made up my mind to do something for the kind-hearted boy so that he couldreally be a member of our class.The next day, I had a special class for willard. I shared his story with the whole class and said, Now,on behalf of the people in need, I should say thanks to willard, you are great! After a silence, all thestudents clapped, saying"Willard, you are great! and they walked to him and hugged him tightly. willardfelt uncomfortable at first when hugging them. He gave a bashful smile as his classmates complimented hiscontribution. Finally, he opened his arms wide to embrace his friends. A friend relationship was built andWillard's silence was broken by a smile on his face.

26.(15分)(1)HNNH(1分)HH(2)烧杯、玻璃棒(2分)(3)(2+2H=C+C-+H2O(1分)防止温度过高次氯酸钠分解为氯化钠和氯酸钠(2分)(4)三颈烧瓶(1分)N2H4·H2O+2NaC1O2NaCl+N2↑+3H2O(2分)(5)停止实验,冷却后补加(1分)(6)酸式(1分)当滴入最后一滴碘标准溶液时,溶液由无色变为蓝色,且半分钟内不褪色(2分)75%(2分)【解析】(1)肼的化学式为N2H4,氮原子之间形成对共用电子,电子式为HNNHH(2)配制30%NaOH溶液的实验步骤为计算、称量溶解,所需的玻璃仪器有量筒、烧杯、玻璃棒(3)锥形瓶的作用是吸收氯气,发生反应的离子方程式是Cl2+2OHCO+C+H2O;由题意知,次氯酸钠易分解,故Ⅱ中用冰水浴控制温度在30℃以下,其主要目的是防止温度过高次氯酸钠分解为氯化钠和氯酸钠(4)仪器A为三颈烧瓶;次氯酸钠具有强氧化性,水合肼具有强还原性,若分液漏斗中溶液的滴速过快N2H4·H2O与NaCO反应的化学方程式为N2H4·H2O+2NaCO=2NaCl+N2↑+3H2O,5)液体加热时为防止暴沸,通常加入沸石,若在蒸馏刚刚开始的时候忘记添加沸石,应停止实验,冷却后补加6)碘标准溶液具有氧化性,可以腐蚀橡皮管,应盛放在酸式滴定管中;达到滴定终点的现象是当滴入最后一滴碘标准溶液时,溶液由无色变为蓝色,且半分钟内不褪色。根据关系式:N2H4·H2O~2l2可知,2.000gN2H4·H2O样品中,n(N2H4·H2O)=+×0.02L×0.3000mol·L-125.0m0.03mol,水合肼的质量分数为m×10%=5%

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