化学IGCSE 试卷答案
山东高一高中化学竞赛测试带答案解析
山东高一高中化学竞赛测试班级:___________ 姓名：___________ 分数：___________一、选择题1.下列关于硅单质及其化合物的说法正确的是（ ） ①硅是构成一些岩石和矿物的基本元素 ②水泥、玻璃、水晶饰物都是硅酸盐制品 ③高纯度的硅单质广泛用于制作光导纤维 ④陶瓷是人类应用很早的硅酸盐材料 A ．①② B ．②③C ．①④D ．③④2.下列反应的离子方程式书写正确的是（ ）A ．用硫氰化钾溶液检验Fe 3＋：Fe 3＋＋3SCN －===Fe(SCN)3↓B ．向海带灰浸出液中加入稀硫酸、双氧水：2I －＋2H ＋＋H 2O 2===I 2＋2H 2OC ．磨口玻璃试剂瓶被烧碱溶液腐蚀：SiO 2＋2Na ＋＋2OH －===Na 2SiO 3↓＋H 2OD ．NaHCO 3溶液和少量Ba(OH)2溶液混合：HCO 3-＋OH －＋Ba 2＋===H 2O ＋BaCO 3↓3.向Na 2CO 3、NaHCO 3混合溶液中逐滴加入稀盐酸，生成气体的量随盐酸加入量的变化关系如图所示，则下列离子组在对应的溶液中一定能大量共存的是（ ）A ．a 点对应的溶液中：Na ＋、OH －、SO 42-、NO 3-B ．b 点对应的溶液中：K ＋、Ca 2＋、MnO 4-、Cl －C ．c 点对应的溶液中：Na ＋、Ca 2＋、NO 3-、Cl －D ．d 点对应的溶液中：F －、NO 3-、Fe 2＋、Ag ＋4.将15.6 g Na 2O 2和5.4 g Al 同时放入一定量的水中，充分反应后得到200 mL 溶液，再向该溶液中缓慢通入标准状况下的HCl 气体6.72 L ，若反应过程中溶液的体积保持不变，则下列说法正确的是（ ）A ．最终溶液：c(Na ＋)＝1.5 mol·L －1B ．标准状况下，反应过程中得到6.72 L 气体C ．最终溶液：c(Na ＋)＝c(Cl －) D ．最终得到7.8 g 沉淀5.在一定条件下，将钠与氧气反应的生成物1.4 g 溶于水，所得溶液恰好能被80 mL 浓度为0.50 mol·L －1的HCl 溶液中和，则该生成物的成分是（ ） A ．Na 2O B ．Na 2O 2 C ．Na 2O 和Na 2O 2 D ．Na 2O 2和NaO 26.在密闭容器中，加热等物质的量的NaHCO 3和Na 2O 2的固体混合物，充分反应后，容器中固体剩余物是（ ） A ．Na 2CO 3和Na 2O 2 B ．Na 2CO 3和NaOH C ．NaOH 和Na 2O 2 D ．NaOH 、Na 2O 2和Na 2CO 37.将4.34 g Na 、Na 2O 、Na 2O 2的混合物与足量水反应，在标准状况下得到672 mL 混合气体，将该混合气体点燃，恰好完全反应，则原固体混合物中Na 、Na 2O 、Na 2O 2的物质的量之比为（ ） A ．1∶1∶1 B ．1∶1∶2 C ．1∶2∶1 D ．4∶3∶28. 已知A 是一种金属单质，B 显淡黄色，其转化关系如下图所示，则C 的以下性质错误的是（ ）A ．溶液呈碱性B ．与澄清石灰水反应产生白色沉淀C ．与足量盐酸反应放出气体D ．受热易分解9.ClO 2是一种杀菌消毒效率高、二次污染小的水处理剂。
历年高中化学奥赛竞赛试题及答案
中国化学会第21届全国高中学生化学竞赛（省级赛区）试题（2007年9月16日 9：00 - 12：00共3小时）题号 1 2 3 4 5 6 7 8 9 10 11 总分满分 12 6 10 7 10 12 8 4 10 12 9100 得分 评卷人● 竞赛时间3小时。
迟到超过半小时者不能进考场。
开始考试后1小时内不得离场。
时间到，把试卷(背面朝上)放在桌面上，立即起立撤离考场。
● 试卷装订成册，不得拆散。
所有解答必须写在指定的方框内，不得用铅笔填写。
草稿纸在最后一页。
不得持有任何其他纸张。
● 姓名、报名号和所属学校必须写在首页左侧指定位置，写在其他地方者按废卷论处。
●允许使用非编程计算器以及直尺等文具。
第1题（12分）通常，硅不与水反应，然而，弱碱性水溶液能使一定量的硅溶解，生成Si(OH)4。
1-1 已知反应分两步进行，试用化学方程式表示上述溶解过程。
早在上世纪50年代就发现了CH 5+的存在，人们曾提出该离子结构的多种假设，然而，直至1999年，才在低温下获得该离子的振动-转动光谱，并由此提出该离子的如下结构模型：氢原子围绕着碳原子快速转动；所有C-H键的键长相等。
1-2 该离子的结构能否用经典的共价键理论说明？简述理由。
1-3 该离子是（ ）。
A.质子酸B.路易斯酸C.自由基D.亲核试剂2003年5月报道，在石油中发现了一种新的烷烃分子，因其结构类似于金刚石，被称为“分子钻石”，若能合成，有可能用做合成纳米材料的理想模板。
该分子的结构简图如下：1-4 该分子的分子式为 ；1-5 该分子有无对称中心？1-6 该分子有几种不同级的碳原子？ 1-7 该分子有无手性碳原子？ 1-8 该分子有无手性？第2题（5分）羟胺和用同位素标记氮原子（N ﹡）的亚硝酸在不同介质中发生反应，方程式如下：NH 2OH+HN ﹡O 2→ A +H 2ONH 2OH+HN ﹡O 2→ B +H 2OA 、B 脱水都能形成N 2O ，由A 得到N ﹡NO 和NN ﹡O ，而由B 只得到NN ﹡O 。
2024年上海普通高中学业水平等级性考试化学真题及答案
2024年上海普通高中学业水平等级性考试化学真题及答案(考试时间60分钟，满分100分)注意：试卷为回忆版。
一、氟及其化合物氟元素及其化合物具有广泛用途。
1.下列关于氟元素的性质说法正确的是A.原子半径最小 B.原子第一电离能最大C.元素的电负性最强D.最高正化合价为+72.下列关于18F 与19F 说法正确的是A.是同种核素 B.是同素异形体C.19F 比18F 多一个电子 D.19F 比18F 多一个中子3.萤石(2CaF )与浓硫酸共热可制备HF 气体，写出该反应的化学方程式：_______，该反应中体现浓硫酸的性质是_______。
A．强氧化性B．难挥发性C．吸水性D．脱水性4.液态氟化氢(HF)的电离方式为：23HF X HF + ，其中X 为_______。
2HF 的结构为F-H F - ，其中F -与HF 依靠_______相连接。
5.回答下列问题：（1）氟单质常温下能腐蚀Fe Ag 、等金属，但工业上却可用Cu 制容器储存，其原因是_______。
6PtF 是极强的氧化剂，用Xe 和6PtF 可制备稀有气体离子化合物，六氟合铂氙[]211[XeF]Pt F -+的制备方式如图所示（2）上述反应中的催化剂为_______。
A.6PtF B.7PtF -C.F -D.XeF +（3）上述过程中属于氧化还原反应的是_______。
A.②B.③C.④D.⑤（4）氟气通入氙(Xe)会产生246XeF XeF XeF 、、三种氟化物气体。
现将1mol 的Xe 和9mol 的2F 同时通入50L 的容器中，反应10min 后，测得容器内共有8.9mol 气体，且三种氟化物的比例为246XeF :XeF :XeF 1:6:3=，则l0min 内4XeF 的速率()4v XeF =_______。
二、粗盐水的精制6.粗盐中含有2224SO ,K ,Ca ,Mg-+++等杂质离子，实验室按下面的流程进行精制：已知：KCl 和NaCl 的溶解度如图所示：（1）步骤①中2BaCl 要稍过量。
上海市普通高中学业水平等级性考试化学卷及答案
202X年X市一般高中学业水公平级性考试化学卷及答案本卷子共6页，含30小题，总分值为100分，考试时量90分钟。
本卷可能用到的相对原子质量数据：H—1 C—12 O—16 S—32 Cl—35.5Na—23 Mg—24 Fe—56一、选择题〔此题包含25小题，每题2分，共50分，每题只有一个选项符合题意〕1．世界气候大会与202X年12月在丹麦首都哥本哈根召开，商讨202X至202X年全球温室气体减排协议。
以下物质属于温室气体的是〔 C 〕A．N2B．H2C．CO2 D．O22．海洋是一个庞大的宝藏，期待着人们的开发和利用。
以下物质不经过化学变化就能从海水中获得的是〔 D 〕A．单质溴 B．单质镁 C．烧碱 D．食盐3．以下行为不是．．健康文明的生活方法的是〔 C 〕A.不偏食，注意营养均衡B.每天坚持适度锻炼C. 沉迷网络聊天、游戏D.不吸烟、不酗酒，远离毒品4．垃圾处理无害化、减量化和资源化逐渐被人们所认识。
垃圾的分类搜集是完成上述理念的重要措施。
某垃圾箱上贴有如右图所示的标志，向此垃圾箱中丢弃的垃圾是〔 B 〕A．危险垃圾B．可回收物C．有害垃圾D．其他垃圾5．当光束通过以下分散系时，能观察到丁达尔效应的是〔 B 〕A．盐酸B．Fe (OH)3胶体 C．氯化钠溶液D．CuSO4溶液6. 实验室制取以下气体时，不能用排气法搜集，而只能用排水法搜集的是〔 D 〕A．NH3B．Cl2C．CO2D．NO7．实验室中，有关试剂的保存方法错误的选项是〔A 〕A．烧碱溶液保存在带玻璃塞的试剂瓶中B．液溴用水封保存C．少量金属钠保存在煤油中D．浓硝酸保存在棕色细口瓶中8．以下实验操作或装置正确的选项是〔 C 〕点燃酒精灯蒸馏过滤稀释浓硫酸A B C D9．据报载我国最近合成新的同位素，其中一种是18572Hf(铪)，它的质子数是 ( A )A.72B.113C.185D.25710. 以下物质中，只含．．共价键的是〔〕A．NaCl B．Na2O C．HCl D．NaOH11．Na2CO3俗名纯碱，下面是对纯碱采纳不同分类法的分类。
1988年-2013年全国高中学生化学竞赛(省级赛区)试题答案及解析
1988 年全国高中学生化学竞赛（初赛）试题参考答案
一、（1）3Na2CO3 + Al2(SO4)3 + 3H2O＝Al(OH)3↓+ 3Na2SO4 + 3CO2↑；现象：白色沉淀和气泡逸出。 Na2CO3 + 2HAc＝2NaAc + CO2↑+ H2O；现象：气体逸出。Na2CO3 + C17H33COOH＝C17H33COONa + NaHCO3；现象：乳状液。产物 NaHCO3 写成 Na2CO3，Na2CO3 和 C17H33COOH 产物为 CO2，Na2CO3 和 Al2(SO4)3产物写成 NaHCO3 均给分 （2）CO2：Na2CO3 + CO2 + H2O＝2NaHCO3； Al(OH)3：Al(OH)3 + 3HAc＝Al(Ac)3 + 3H2O； C17H33COONa：C17H33COONa + HAc＝C17H33COOH + NaAc 二、卡车在起动、刹车时排出黑色废烟者，是以柴油为燃料的。柴油分子中碳原子数目多于汽油分子
，所以沸点高。7 无氢键，沸点低于 6。
十、1．α－氰基，α－丁烯酸乙酯；2．
1990 年全国高中学生化学竞赛（初赛）试题参考答案
一、（1）Cu、Zn 或其他；（2）C、P 或其他；（3）Al、Fe 或其他；（4）Au、Pt 或其他 二、H2SO3+1/2O2＝H2SO4；H2SO4 酸性比 H2SO3 强
五、A．C5H10O4 B．C4H8O4 C．C4H6O4 略
六、（1）
Si－O 交替成六、八元坏都给 2 分；（2）
写出
交联结构给 3 分。 七、（1）6FeC2O3 + 3H2O2 + 6K2C2O4＝2Fe(OH)3 + 4K3Fe(C2O4)3（由于溶液显碱性所以有部分
IGCSE chemistry 化学试卷 2016-specimen-paper-5
This document consists of 9 printed pages and 1 blank page.© UCLES 2014 [Turn over*123456789*BIOLOGY 0610/05Paper 5 Practical Test For Examination from 2016SPECIMEN PAPER 1 hour 15 minutesCandidates answer on the Question Paper.Additional Materials: As listed in the Con fi dential Instructions.READ THESE INSTRUCTIONS FIRSTWrite your Centre number, candidate number and name on all the work you hand in.Write in dark blue or black pen.You may use an HB pencil for any diagrams, graphs or rough working.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.At the end of the examination, fasten all your work securely together.The number of marks is given in brackets [ ] at the end of each question or part question.Cambridge International ExaminationsCambridge International General Certi fi cate of Secondary EducationThe syllabus is accredited for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.peroxide into water and oxygen. The activity of this enzyme can be measured by collecting the oxygen produced.2H 2O 2 → 2H 2O + O 2hydrogen peroxide water oxygenHydrogen peroxide can irritate the skin and damage the eyes. Use the eye protection and plastic gloves provided.You will use the apparatus shown in Fig. 1.1 to compare the activity of catalase using pieces of sweet potato of different sizes.Read through the method below before starting the experiment.In the space in Question 1(a), prepare a table in which to record your results. You are provided with a slice of sweet potato and three test-tubes each containing 5 cm 3 of hydrogenperoxide solution.●Remove the outer layer from around the slice of sweet potato. ● Cut three cubes from the slice. Each cube should be 10 mm × 10 mm × 10 mm.● Set up the apparatus as in Fig. 1.1. Make sure the end of the delivery tube is below the levelof the water in test-tube B .waterdeliverytubebung AB Fig. 1.1●Remove the bung from test-tube A , and place one of your three cubes of sweet potato (cube 1) into this test-tube.●Empty the contents of one of the test-tubes labelled hydrogen peroxide into test-tube A .●Immediately replace the bung in test-tube A . Bubbles of gas will begin to appear as soon as the solution makes contact with the cube. ●Begin timing when the first bubble comes out of the delivery tube and count the numberof bubbles that escape into the water in test-tube B for a period of 1 minute. Record this result in your table at 1(a).●After another minute, measure the height of the foam in test-tube A.Record this result.●Discard the contents of test-tube A into the container labelled waste washings, and rinse thetest-tube with water.●Take the second cube of sweet potato (cube 2) and cut this into two smaller pieces ofapproximately the same size.●Put both of these pieces from cube 2 into test-tube A and repeat the procedure.●Record your results for cube 2 in your table.●Discard the contents of test-tube A into the container labelled waste washings,and rinse thetest-tube with water.●Cut the third cube of sweet potato (cube 3) into eight smaller pieces.●Put all eight pieces into test-tube A and repeat the procedure.●Record your results for cube 3 in your table.Use this space for your table of results.(a)[6](b)(i) State two variables that were kept constant in this investigation.1 ........................................................................................................................................2 (2)(ii) Suggest how you could improve the method you have followed................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (3)What conclusion can be drawn from your results?(c)......................................................................................................................................................................................................................................................................................................................................................................................................................................................... (1)(d)(i) Some students were given a hypothesis that said,"the activity of catalase increases with increasing temperature".Describe a similar investigation to the one you have carried out in (a) to test this hypothesis.Do not carry out this experiment.......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (6)(ii) Outline one safety precaution that you would need to take when performing your experiment............................................................................................................................................ (1)[Total: 19]2 W1 is a simple leaf from a dicotyledonous plant.(i) Make a large, labelled drawing of the lower surface of the leaf.(a)[5](ii) Describe two visible ways in which the upper surface of W1 is different from the lower surface.1 ...................................................................................................................................................................................................................................................................................2 ........................................................................................................................................ (2)(b)Place W1 on the 1 cm2 grid printed below and draw a clear outline to show the edges of the leaf.(i) Use your outline to calculate the surface area of the leaf. (1)(ii) Describe the method you used to determine the surface area of the leaf.................................................................................................................................................................................................................................................................................................................................................................................................................................. (2)(c)A student investigated the effect of different wind speeds on the rate of transpiration of someleaves.The student took fi ve leaves from a tree and weighed each of them on a balance.Each of the leaves was then hung from a different piece of wire.Fans were used to blow air at different speeds over each leaf.After 12 hours, the student weighed each leaf again. The results are shown in Table 2.1.Table 2.1wind speed / m per s mass of leaf atthe start / gmass of leaf atthe end / gloss in mass/ g0 5.7 3.81 5.3 3.33 5.9 3.76 5.1 2.68 5.3 2.6(i) Calculate the loss in mass for each leaf. Complete Table 2.1. [2](ii) Construct a graph to show the loss in mass against wind speed.[5](iii) Use your graph to determine the loss in mass at a wind speed of 10 m per s. Show on the graph how you obtained your answer......................................................... g [2] (iv) A student criticised the results by saying that the loss in mass does not allow for a fair comparison between leaves.Suggest a more appropriate calculation and explain why it gives a fairer comparison.................................................................................................................................................................................................................................................................................................................................................................................................................................. (2)[Total: 21]BLANK PAGEPermission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.。
上海市高中学生化学竞赛暨华理化工杯初赛试题和答案(word)
（“华理—化工杯”）初赛试题可能用到的相对原子质量（原子量）：H-1、C-12、N-14、O-16、F-19、Na-23、Mg-24、Al-27、S-32、Cl-35.5、K-39、Ca-40、Cr-52、Mn-55、Fe-56、Co-59、Cu-64、Zn-65、Br-80、Ag-108、I-127、Ba-137、Pb-207一、选择题1、下列日常生活用品中的化学物质添加错误的是……………………………（）A．含氟牙膏中加入氟化钠B．加碘食盐中加入碘酸钾C．高钙牛奶中加入氧化钙D．富铁麦片中加入铁粉2、下列芳香族有机物在常温下呈液态的是……………………………………（）A．萘B．苯酚C．三硝基甲苯D．溴苯3、钡离子具有毒性，但在肠胃放射性检查中，却常服用“钡餐”。
为减少微量溶解的钡离子对人体的伤害，“钡餐”中含有一种保护成分，其可能为A．碳酸钡B．硫酸钠C．稀硫酸D．碳酸钠4、下列有关甲醛的化学用语表示正确的是……………………………………（）A．比例模型：B．电子式：C．结构式：HCHO D．最简式：CH2O5、许多物质除了人工合成外，在自然界中也能产生，下列说法错误的是…（）A．鸡蛋腐败产生硫化氢B．成熟的苹果能释放放出乙烯C．粮食发酵产生乙醇D．一些树木表皮可以分泌出酚醛树脂6、下面是有关微粒的若干相关物理量…………………………………………（）1个12C原子质量的1/12=X g1个氢原子的直径=Y m1个氧分子所有电子的质量=Z g若只考虑数字，则这些物理量的数值大小关系为A．X>Y>Z B．Y>X>Z C．Y>Z>X D．Z>X>Y7、下列物质中，n(阳离子)/n(阴离子)等于1的是………………………………（）A．稀盐酸B．碳酸氢钠溶液C．碳化硅晶体D．草酸晶体8、硫循环与碳循环是自然界中两种重要的元素循环过程，下列有关这两种循环的说法正确的是……………………………………………………………………（）A．碳循环过程中碳元素会进入大气，而硫元素则不会进入大气B．碳循环过程有生物圈参与，而循环过程无生物圈参与C．人类活动对碳循环和硫循环都造成巨大影响D．碳元素可以有机物形式参与循环，而硫元素都以无机物形式参与循环9、原子吸收一定的能量后，电子会跃迁到较高能级的轨道上，成为激发态原子，化学反应活性也随之增大。
IGCSE考试 化学历年真题 2002年9月1
CHEMISTRY (2)Paper 0620/01 Multiple Choice (2)Paper 0620/02 Paper 2 (Core) (4)Paper 0620/03 Paper 3 (Extended) (8)Paper 0620/04 Coursework (13)Paper 0620/05 Practical Test (14)Paper 0620/06 Alternative to Practical (15)Paper 0620/01 Multiple ChoiceQuestion Number KeyQuestionNumberKey1C21B2B22D3A23A4D24B5A25D6C26B7A27D8A28D9B29D10C30B11B31D12D32D13C33A14D34A15B35B16C36A17A37A18C38B19A39C20C40CGeneral commentsThe candidates achieved a mean mark of 28.0 with a standard deviation of 6.59. These values are satisfactory. The Paper is intended, primarily, to discriminate between candidates in the grade C to grade G range. H owever, the Paper is also taken by candidates who achieve higher than grade C. As a consequence, the mark distribution tends to be skewed towards higher marks. This report concentrates more on the responses made by the grade C to G candidates. Similarly, there were several questions, e.g. Questions5, 6, 7, 15, 24, 30, 36 and 38, that were found, overall, to be on the easy side but yet discriminated very well across the ability range.Questions 26 and 27 also had relatively high facilities: they discriminated well but not as well as the 8 questions just mentioned.Comments on specific questionsQuestion 4A relatively hard question that discriminated well. ResponseB was relatively popular amongst the lower scoring candidates, the implication being that these candidates did not realise that a soluble impurity affects the m.p. and b.p, of the solvent in opposite directions.Question 6Perhaps because it was presented in numerical form rather than diagrammatic form, this question proved to be an ‘either or’ question with very few takers for responses A and D.Question 8The higher scoring candidates found this question quite easy but their lower scoring colleagues favoured response B. There seems to be no obvious reason for this.Question 9As for Question 8, the higher scorers thought their way through the details but response C attracted nearly 60% of the lower scorers. Did they forget that the oxygen molecule is diatomic?Question 16Nearly a third of the lower scorers chose A - slightly more than those in this group who answered correctly. Presumably this is due to simple misremembering of the colours of hydrated and anhydrous copper(II) sulphate.Question 18Half of the lower scorers chose A rather than the key, C. It is not good practice to have a sealed reaction vessel with a gaseous product involved. Quite apart from that pragmatic point, there would be no change in reading of the balance. These candidates needed to be a little more thoughtful.Question 19The popularities of all four responses were very roughly equal amongst the lower scoring candidates with B slightly the most popular. It seems almost impossible to convince the majority of candidates that copper does not react with dilute acids.Question 25Only half of the candidates answered correctly. Amongst the lower scoring candidates, responses A and B together accounted for 60% of their choices. This seems to be a somewhat surprising lack of recall. Question 29This question was found hard across the ability range. The relative popularities of responses B and C were fairly equal for both the lower scoring and the higher scoring groups. This suggests that there was much guessing. It seems that candidates did not take on board the reference in the question to “economic” and the fact that the water does not need to be very pure.Question 32Disregard for practicalities was also evident in the response to this question. All of the techniques mentioned in the question can be used to prevent rusting but neither coating with grease nor electroplating are very realistic in respect of a large object such as a girder for a bridge.Paper 0620/02Paper 2 (Core)General commentsMany of the candidates tackled the Paper well and there were many good answers showing a thorough grasp of the subject matter. Many candidates scored over three-quarters of the marks available. In general, the rubric was generally well interpreted and most candidates attempted all parts of each question. The standard of English was generally good. Atomic structure and general inorganic reactions were well known but, as in previous years, many of the candidates found it difficult to explain terms such as thermal decomposition, compound and element convincingly. There were few instances in this particular Paper where candidates disadvantaged themselves by giving multiple answers and it is encouraging to note that most candidates confined themselves to a single answer when requested. It was also encouraging to note that the majority of the candidates were able to write correct formulae in the appropriate places and showed a good ability at balancing equations. A considerable number of candidates appeared to have difficulty in explaining the results from graphs and interpolating data e.g. Question6(c)(i). The general properties of elements as tested in Question3(d) and tests for particular groups e.g. Question5 (a) proved a stumbling block for many candidates. It was encouraging to note, however, that answers to questions on changes of state and the Periodic Table showed an improvement over those set in previous years.Comments on specific questionsQuestion 1This appeared to be the most accessible question on the Paper. Most candidates achieved at least 10 marks on this question, the lowest scoring part usually being (c) where the idea of moving ions transferring the charge in molten sodium chloride is still not well appreciated.(a)At least three quarters of the candidates achieved 5 marks on this question. Parts (i), (iii), (v) and(vi) were practically always correct. Many candidates however, suggested, incorrectly, that metals formed acidic oxides (part (ii)), with potassium or sodium being the most often seen mistakes. A variety of answers were seen for part (ii) with bromine and oxygen often being seen as incorrect answers. It is clear that many candidates ignored or did not appreciate the meaning of the word ‘giant’ in the question.(b)Practically all candidates achieved full marks for this part. It is encouraging that candidates seemto have a better knowledge of the uses of chemical elements than in previous years.(c)(i)Most candidates realised that the bonding was covalent and hardly any gave foolish answers.(ii)Although the majority of candidates put the correct formula BrF5, a few failed to read the letters correctly and put NaC l (for compound B) or failed to count the correct number of fluorine atoms.BrF and BrF4 were the commonest incorrect answers.(iii)The commonest error here, which has been commented on in previous Examiner’s Reports, was to suggest that electrons are responsible for the conduction in a molten ionic substance. This may arise from the fact that electrons are responsible for metallic conduction where they may learn about ions in a sea of electrons. A minority of candidates also suggested that the ions dissolved in water and were then able to move. This is perhaps a misinterpretation of the meaning of the term ‘molten’.Question 2This question was surprisingly poorly attempted even by some fairly high scoring candidates, and full marks were rarely recorded for parts (a)(iii) and (e).(a)Many candidates wrote rather vague answers here such as ‘heat it’ or ‘pull the string’.(b)(i)Most candidates plotted the points well, but a significant minority failed to plot the 0-0 point (or evento draw the line between 0 and 23).(ii)Most candidates were able to draw a suitable curve as a line of best fit missing one of the points at either 2 or 3 minutes. However, a considerable number of candidates drew straight lines from point to point and this could not be given credit. A few candidates drew a straight line from 0 to 55, even though the points clearly fell on a curve.(iii)This was not always well done and many candidates only scored one mark, usually for suggesting that the reaction was finished. Many candidates failed to gain the mark for suggesting that the zinc had all been used up because they suggested that the reactants or reactant had been used up.Candidates should be encouraged to refer back to the stem of a question. In this case, the clue lies in the fact that the hydrochloric acid is in excess.(c)Most candidates realised that the reaction went faster at a higher temperature but many failed torealise that the final volume of gas remains more or less the same. Even accounting for expansion, many candidates made the final volume of gas far too high.(d)(i)Nearly all candidates obtained the mark for the balancing of the equation.(ii)Most candidates correctly added the atomic mass of zinc and two chlorines together to get an answer of 136. A few candidates, however either used a mass of chlorine of 35 rather than the35.5 from the Periodic Table and calculated the incorrect answer of 135.(iii)This was poorly attempted, even by a number of high-scoring candidates. Many answers were too vague and referred to ‘pure substances’, ‘chemicals in the Periodic Table’ or ‘the smallest unit of a substance’. Candidates who wrote along the lines of ‘a substance which cannot be broken down’had to put the rider ‘by chemical means’ to gain the mark.Question 3This was reasonably well done by the majority of candidates, but it was disappointing to note that few could identify the type of chemical reaction occurring between ammonia and hydrochloric acid or could explain part (g)(ii) adequately.(a)This was reasonably well done by most candidates but at least 20% of the candidates reversedsteps B and C, perhaps by reading the diagram round in a clockwise direction without taking note of the letters. Cooling was sometimes seen as an incorrect answer for both parts (ii) and (iii). (b)Most candidates correctly identified a liquid state as involving molecules sliding over each other.The most common error was to suggest that the molecules were moving completely freely from each other.(c)Although there were a variety of responses for which letter represented an endothermic change,more candidates could describe that an endothermic change involved absorbing heat or taking in heat. Although it was marked correct on this occasion the idea of the reaction ‘needing heat’ is deemed to be rather vague.(d)(i)The incorrect answer, bromine, was not uncommon, presumably because many candidates hadseen bromine vapour in diffusion experiments. Sulphur was also not uncommonly thought to be a gas, presumably because it is below oxygen in the Periodic Table and next to chlorine.(ii)The incorrect answer ‘chlorine’ was often seen here.(iii) A surprisingly large number of candidates failed to recognise sodium chloride as the correct answer. Iron was often given as an answer. Presumably these candidates did not recognise or act on the word ‘compound’ in the question.(e)(i)Many candidates wrote Brownian Motion in place of diffusion. This cannot be accepted as correctbecause ammonia and hydrogen chloride are of the same order of size.(ii)Although ammonium chloride was written by most candidates, a considerable minority suggested either nitrogen trichloride or another nitrogen compound. Quite a few candidates penalised themselves through inaccuracy by putting ammonia chloride.(iii)The commonest incorrect response referred merely to higher concentrations at one end compared with the other. It was encouraging to note that many candidates were able to work out the correct reason in terms of either differences in mass or differences in speed.(f)The responses to this question were more often than not incorrect. Many candidates failed torecognise the key word ‘chemical’ in the question and wrote exothermic as an incorrect answer. A considerable number of candidates thought, incorrectly, that the reaction was an example of a redox reaction.(g)(i) Nearly all candidates recognised the thermometer, the commonest incorrect answer being ‘ameasuring tube/cylinder’.(ii)Many candidates failed to gain a mark for this part because they did not refer at all to the solid.The answer required more than just reference to the boiling point of water. Some candidates referred, incorrectly to the dissolving of the solid rather than melting or to the boiling point of the solid.(iii)This was answered well by the majority of candidates, the commonest errors being to suggest that rates of reaction were involved or that the solid needed to dissolve in the water.Question 4This question was reasonably well attempted by many candidates, but the sections involving definitions were often poorly written.(a)(i)Many candidates understood that thermal decomposition involved heat, but fewer explained themeaning of decomposition. Candidates should realise that words in italics in the Exam Paper need full explanation. In this case the meaning of decomposition needs to be explained as well as the word thermal. Answers just suggesting ‘decomposing’ were held to be too close to the word ‘decomposition’ to merit the mark.(ii)Most candidates could explain that a catalyst speeds up the rate of a reaction. The idea that a catalyst just alters the rate of reaction is regarded as rather too vague and this has been commented on in previous Examiner’s Reports.(b)Most candidates suggested that ethene was the unsaturated compound and only a few put ethane.(c)(i)Many candidates failed to give the correct answer to this question through not using the informationin the table and gave one of the products rather than the name of a fraction. Petrol or diesel were not uncommon incorrect answers, given through not reading the question thoroughly enough.(ii)90g was a not uncommon incorrect answer but about two-thirds of the candidates gave the correct answer of 4000g. Only a few candidates penalised themselves by giving the incorrect units.(iii)The equation was completed correctly by most candidates, although a large minority put methane down as one of the products or tried to put a number in front of the C2H6.(d)(i)In previous years, candidates have often found the writing of formulae for polymers difficult.Although, the polymer in this case is very simple, and it is encouraging that a large number of candidates succeeded in gaining the mark here, the Examiners are still finding a great number of mistakes in the writing of the formulae. Common errors included, writing the formulae out but not joining them together, the inclusion of the double bonds still and the lack of ‘continuation bonds’.Formulae showing cycloalkanes were not uncommon as were formulae with hydrogen atoms terminating either end of the chain.(ii)This was only answered correctly by about half the candidates. Apart from the incorrect answer ‘condensation polymer’, other incorrect answers often seen referred to names of chemicals rather than a type of polymerisation e.g. plastic, polythene, butane.Question 5This was one of the most poorly answered questions on the Paper for many candidates. The tests for ions were often not known and the definition of the word compound given by most candidates was often extremely vague.(a)Although many candidates had learnt the tests for ions and gained full marks for this section, aconsiderable minority failed to gain any marks through not knowing the correct solutions to be added. It is to be noted that, although many candidates know tests for gases such as carbon dioxide and hydrogen, when it comes to learning the tests for specific ions, the lower scoring candidates are overwhelmed by the number of tests required. Many candidates merely put down sodium hydroxide as a test for all the ions in the left hand column. Sodium chloride was sometimes seen as an incorrect test for iron(II) ions and starch was often reported to be a test for iodide ions, presumably through mistaken identification with the test for iodine. A number of candidates lost marks through suggesting adding the wrong acid for dissolving a presumed precipitate, although the acid was not essential in this case because the ions were already in solution. Adding hydrochloric acid for testing for chloride ions or sulphuric acid for testing for sulphate ions can hardly be given credit, although this does not negate the mark for the colour of the precipitate. (b)Most candidates scored at least 2 of the 3 marks available for this part. The two most commonerrors were to either not make clear that the filtrate was sodium chloride solution or the omission of the crystallisation step. Those candidates who drew annotated diagrams, generally scored more marks. Candidates should be reminded, however, that it is essential to annotate the diagrams, since it is not obvious that the filtrate is sodium chloride, as evinced by the fact that a number of candidates labelled the precipitate on the filter paper as being sodium chloride.(c)As in previous examinations, where a similar question has been asked, candidates find it difficult toexplain the meaning of chemical terms and this question proved to be a good discriminator. Many candidates are still under the impression that a compound is a mixture of elements or do not mention that the different elements/atoms are bonded.(d)(i)This was well answered by most candidates, the only error being to confuse the electrode productsby putting sodium here. Chloride was another incorrect answer, because it is not a final product.(ii)This was less well answered than part (i) with the most common incorrect response being hydrogen. This is a common error arising from the candidates’ misunderstanding of the term molten (as also commented on in Question1).Question 6This question proved to be fairly low scoring for many candidates especially in part (b) and (c)(i), where an interpretation of the properties in the table was required.(a)Most candidates gave a correct response. The most common incorrect response was zinc orcopper, the candidates presumably confusing extraction with purification.(b)Many candidates referred to the activity series, reactivity of the elements or the formation of anoxide layer, rather than focusing on the need for electricity to extract aluminium.(c)(i)Many candidates failed to gain full marks here because they did not read the information in thetable carefully enough and did not give responses indicating a gradation between magnesium and zinc. Candidates were most likely to obtain the marks if they made clear statements along the lines of ‘less .... than magnesium but more ....than zinc’. Some candidates failed to use the information in the table at all and wrote answers to do with radioactivity. Repeating statements in the observation boxes for magnesium or zinc did not gain any credit. Some candidates failed to gain a mark because they referred to magnesium in the central box rather than uranium.(ii)This was answered well by most candidates, although a small number used the term relative atomic mass rather than mass number.(iii)Most candidates referred to nuclear energy or nuclear bombs but a significant minority of candidates failed to obtain the mark because they merely referred to a fuel without any further clarification.(d)This mark was obtained by most candidates. A minority suggested, incorrectly, that magnesiumhydroxide would be formed.(e)(i)Although most candidates realised that an alloy was a mixture of metals, some wrote rathervaguely about it being just a mixture of elements or non-metals or mentioned compounds and forming covalent bonds between metals. These latter ideas were not given credit.(ii)Many candidates tended to give a long list of properties of metals without making any comparison with the metals alone. Some of these properties such as increase in melting point are not valid.There were many vague answers such as ‘it improves the properties of the metal’ or ‘makes it better for a particular job’. Candidates should be encouraged to write an answer with a specific correct property in mind.(f)This part was poorly answered because many candidates did not refer to carbon as the reducingagent and only mentioned the zinc oxide. Candidates should also be encouraged to be more accurate with their wording. There were many vague statements and many candidates opting for an answer based on oxidation numbers or electrons failed to gain the mark through incorrect statements such as ‘the carbon gains electrons’. At foundation level, candidates should be encouraged to choose the simplest method of expression e.g. ‘the carbon removes the oxygen from the zinc oxide’.(g)(i)Most candidates realised that the double headed arrow referred to a reversible reaction.(ii)Although most candidates gave a good approximation of the percentage of nitrogen in the air, common errors were 70% (rounding down from 78%?) and 20% (mistaken for oxygen?).(h)(i)About 90% of the candidates drew a correct diagram of the electronic structure of magnesium. Ofthose who did not, the most common errors appeared to be the addition of another shell of 8 electrons below the valency shell or 4 electrons in the outer shell.(ii)About one third of the candidates obtained only a single mark because they did not refer to the number of electrons transferred or the electrons in the valency shell being transferred.Paper 0620/03Paper 3 (Extended)General commentsThere remains the perennial problem of the candidates for whom this Paper is far too challenging and consequently their level of attainment is predictably extremely low. This issue was discussed in the Report for November 2002 and these comments are increasing germane to the entry of candidates in future examinations. As has been said before:-For some candidates who have been entered for Paper 3, it presents an inappropriate test of their skill and knowledge and they attain very low marks or hand in blank scripts. This Paper is not one that inspires them to make full use of whatever knowledge and aptitude they may possess. From 2004, candidates can only be entered for Paper 2 or Paper 3 and not both as in the past. In the future, candidates should be entered for Paper 3 if they expect to achieve grade D or higher. Being entered for this higher and more demanding Paper could reduce an individual’s chances of attaining their optimum grade, as Paper 2 is designed to allow candidates expected to gain a C or below to show their skills better and to concentrate on core concepts. Candidates who are correctly entered should find preparing for and sitting the examination a more positive and rewarding experience that best allows them to demonstrate their abilities to the full.At the other end of the attainment range, there a significant cohort of candidates who displayed a most creditable knowledge and understanding of Chemistry. They deserve the highest praise and commendation for their undoubted diligence and achievement.Candidates continue to persist in trying to write symbol equations when the less demanding word equation has been requested.There was ample evidence that candidates are not considering exactly what is required to answer the question and offering irrelevant or incorrect answers.The quality of the diagrams this year was disappointing and future entrants might well profit by practising this essential skill.Comments on specific questionsQuestion 1(a)The major difficulty was the balancing of the equations. The equation with carbon dioxide as aproduct proved to be more challenging than the alternative with carbon monoxide as a product.Typical errors were as follows.Fe2O3 + C = 2Fe + 3COFe2O3 + C = 2Fe + 3CO2Fe2O3 + 3C = 2 Fe + 3CO2Fe2O3 + C = 2 Fe + CO3Fe2O3 + 3C = Fe2 + 3CO2Fe2O3 + C = 2 FeO + CO(b)(i)The equation for the reduction of iron(III) oxide by carbon monoxide was given on many scripts aswas the equation for the formation of carbon monoxide. 2C + O2 = 2CO. Inevitably, despite comments in a number of these reports, word equations featured on many scripts. When a word equation is required, it is specifically requested. The highly exothermic reaction in this process is:C + O2 = CO2.(ii) A number of explanations were accepted. These ranged from the incomplete combustion of carbon, carbon dioxide reduced by coke and higher in the furnace, most of the oxygen had been used up so the reaction that occurred was: 2C + O2 = 2CO. The most frequent errors were to givea discussion of the role of carbon monoxide as a reductant for the iron(III) oxide and to correctlystate that carbon reacted with oxygen to form carbon dioxide, which was then wrongly thought to be reduced by oxygen to carbon monoxide.(c) A wide range of word equations was accepted, the use of trivial names was permitted. Thefollowing examples illustrate the diversity of the equations that were credited with both marks.lime + sand = slaglimestone + silica = slag + carbon dioxidecalcium oxide + silicon(IV) oxide = calcium silicateA correct symbol equation also gained the marks.A common mistake was to believe that the impurity was silicon not its oxide.(d)(i)Almost all the entry could state a use of stainless steel ranging from garden tools to kitchenequipment.(ii)Nickel or chromium were the usual and correct responses. Errors were to suggest aluminium, zinc, carbon, copper or tin.(iii)The most serious and unfortunately quite common mistake was to describe the blast furnace and not the Basic Oxygen Process. Another difficulty was that some candidates were not clear about the role of the reagents, did they reduce the ore or the amount of carbon in the impure iron or remove the oxides of silicon etc?However there were many excellent answers of the type:Oxy gen was blown through the impure iron, it oxidised the impurities to their oxides. Carbon dioxide escaped as a gas. Lime was added, this removed the silicon(IV) oxide as slag.The marking scheme was sufficiently flexible to acknowledge a wide range of appropriate comments.(e)In general many candidates understood the concept of plating metal on metal by electrolysis, thisquestion was well answered. The response that caused the most difficulty was the identification of the electrolyte, errors were – molten tin, solution of tin, an iron salt, sulphuric acid or sodium hydroxide. A named tin salt, a tin salt or tin ions were the correct answers. Another difficulty was to reverse the tin and the iron, that is the anode made of iron and the cathode made of tin.Question 2(a)(i)Very well answered, a small minority gave the electron distribution instead of the valency.(ii)The marking points were any two from the following:meltingor boiling point· high· hard·poor conductor of electricity or heat· brittle.Insoluble, dull, or not malleable were not accepted.(iii)Many did not heed the request – an element with a macromolecular structure and then a macromolecular compound and gave two elements.(iv)Useful advice that might be offered to future candidates – do not make the diagram too complicated, for example the structure of diamond can be illustrated with five carbon atoms and that of silicon(IV) oxide by one silicon and four oxygen atoms. Some of the more artistic candidates drew quite complex and accurate diagrams and for those with the necessary skills it is to be encouraged but for the majority of candidates simplicity is the best option.For carbon or silicon(IV) oxide the Examiners were looking for 1:4 co-ordination, a suggestion of tetrahedral geometry or evidence of continuation.The link between parts (iii) and (iv) was not insisted upon and any correct macromolecular structure was accepted in (iv). This extended the range of possible answers to include organic macromolecules, nylon 66, poly(ethene) and starch were all given.(b)(i)(ii)Probably due to the influence of practical work, most of the candidates had some knowledge ofthese reactions. Many answers were spoilt by the inappropriate phrasing of the responses. It is essential the two parts are kept separate: addition of aqueous sodium hydroxide - a white precipitate forms: excess sodium hydroxide - this dissolves or it is soluble in excess (to give a colourless solution)Careless use of the words “soluble” and “insoluble” completely negated some potentially correct descriptions.(c)The correct solution to this problem is:(i)number of moles CO2 = 0.24/24 = 0.01number of moles of CaCO3 and MgCO3 = 0.01number of moles of CaCO3 = 0.005。
igcse 化学2015年选择题
Additional Materials:
Multiple Choice Answer Sheet Soft clean eraser Soft pencil (type B or HB is recommended)
0620/11 May/June 2015
45 Minutes
READ THESE INSTRUCTIONS FIRST
natural gas combustion of natural gas
C
D
final temperature initial temperature
heat thermal decomposition of limestone
acid reaction of acid with alkali
alkali
© UCLES 2015
0620/11/M/J/15
3
3 Atoms contain electrons, neutrons and protons. What is the definition of nucleon number? A the number of neutrons in the nucleus of an atom B the number of protons in the nucleus of an atom C the total number of neutrons and protons in the nucleus of an atom D the total number of particles in an atom
only electrons and neutrons are charged
© UCLES 2015
化学IGCSE试卷
This document consists of 16 printed pages.IB11 06_0620_11/2RP© UCLES 2011[Turn over*9373386046*UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary EducationCHEMISTRY 0620/11Paper 1 Multiple Choice May/June 201145 MinutesAdditional Materials: Multiple Choice Answer Sheet Soft clean eraserSoft pencil (type B or HB is recommended)READ THESE INSTRUCTIONS FIRSTWrite in soft pencil.Do not use staples, paper clips, highlighters, glue or correction fluid.Write your name, Centre number and candidate number on the Answer Sheet in the spaces provided unless this has been done for you.There are forty questions on this paper. Answer all questions. For each question there are four possibl e answers A , B , C and D .Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet.Read the instructions on the Answer Sheet very carefully.Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. A copy of the Periodic Table is printed on page 16. You may use a calculator.w w w .X t r e m e P a pe r s .c o m© UCLES 2011 0620/11/M/J/111 The diagrams show the arrangement of particles in three different physical states of substance X.state 1state 2state 3Which statement about the physical states of substance X is correct? A Particles in state 1 vibrate about fixed positions. B State 1 changes to state 2 by diffusion.C State 2 changes directly to state 3 by condensation.D The substance in stage 3 has a fixed volume. 2 An aqueous solution is coloured.Which method of separation would show that the solution contains ions of different colours? A chromatography B crystallisation C distillation D filtration3 The table gives the solubility of four substances in ethanol and in water. A mixture containing all four substances is added to ethanol, stirred and filtered.The solid residue is added to water, stirred and filtered.The filtrate is evaporated to dryness, leaving a white solid.Which is the white solid?solubility inethanol water A insoluble insoluble B insoluble soluble C soluble insoluble D soluble soluble© UCLES 2011 0620/11/M/J/11[Turn over4 Which two elements react together to form an ionic compound?element electronic structure W 2,4 X 2,8 Y 2,8,1 Z 2,8,7A W and XB X and YC Y and ZD Z and W5 The diagram shows part of the Periodic Table.ACBDWhich element is correctly matched with its electronic structure?electronic structure A2,8,1 B 2,4 C 2,8,2 D 2,86 In the diagrams, circles of different sizes represent atoms of different elements. Which diagram represents hydrogen chloride gas?BACD7The nucleon number and proton number of the lithium atom are shown by the symbol Li73.What is the correct symbol for the lithium ion in lithium chloride?A 62Li− B 63Li+ C 73Li+ D 73Li−8What is the relative molecular mass (M r) of HNO3?A 5B 31C 32D 639Electricity from a power station passes through overhead cables to a substation and then to a school where it is used to electrolyse concentrated hydrochloric acid using inert electrodes.Which substances are used for the overhead cables and for the electrodes?overheadcables electrodesA aluminium copperB aluminium platinumC copper platinumD platinum aluminium10 Which statement about the electrolysis of molten lead(II) bromide is correct?A A colourless gas is seen at the cathode.B A grey metal is seen at the anode.C A red/brown gas is seen at the anode.D A red/brown metal is seen at the cathode.© UCLES 2011 0620/11/M/J/1111Electricity is passed through concentrated aqueous sodium chloride, as shown.What is the test for the gas formed at the positive electrode?A bleaches damp litmus paperB ‘pops’ with a lighted splintC relights a glowing splintD turns damp red litmus paper blue12Three processes are listed.burning methane in airradioactive decay of 235Ureacting hydrogen with oxygen.Which statements about these processes are correct?1 Hydrogen and methane are being used as fuels.2 All the processes involve oxidation.3 All the processes are used to produce energy.A 1 and 2 onlyB 1 and 3 onlyC 2 and 3 only D1, 2 and 3© UCLES 2011 0620/11/M/J/11 [Turn over13Butane, ethanol and hydrogen are fuels.Which substances produce both carbon dioxide and water when used as a fuel?butane ethanol hydrogenABCD14The equation for the effect of heat on hydrated sodium carbonate is as shown.Na2CO3.10H2O(s) Na2CO3(s) + 10H2O(g) Statements made by four students about the reaction are given.P Anhydrous sodium carbonate is formed.Q Steam is formed.R There is a colour change from blue to white.S The reaction is reversible.Which students’ statements are correct?A P, Q and R onlyB P, Q and S onlyC Q, R and S onlyD P, Q, R and S© UCLES 2011 0620/11/M/J/11© UCLES 2011 0620/11/M/J/11[Turn overFor which two reactions would the apparatus be suitable?reaction 1 AgNO 3(aq) + HC l (aq) → AgC l (s) + HNO 3(aq) reaction 2 2H 2O 2(aq) → 2H 2O(l) + O 2(g)reaction 3 MgO(s) + 2HC l (aq) → MgC l 2(aq) + H 2O(l)reaction 4ZnCO 3(s) + 2HC l (aq) → ZnC l2(aq) + CO 2(g) + H 2O(l)A 1 and 2B 1 and 3C 2 and 4D 3 and 416 A student investigates the rate of reaction between magnesium and excess sulfuric acid.The volume of hydrogen given off in the reaction is measured over time.The graph shows the results of two experiments, R and S.volume of hydrogen given offtimeWhich change in conditions would cause the difference between R and S?A A catalyst is added in S.B The acid is more concentrated in R than in S.C The magnesium is less finely powdered in R than in S.D The temperature in R is lower than in S.17Carbon dioxide is an acidic oxide that reacts with aqueous calcium hydroxide.Which type of reaction takes place?A decompositionB fermentationC neutralisationD oxidation18 Which is not a typical property of an acid?A They react with alkalis producing water.B They react with all metals producing hydrogen.C They react with carbonates producing carbon dioxide.D They turn litmus paper red.19 A solution contains barium ions and silver ions.What could the anion be?A chloride onlyB nitrate onlyC sulfate onlyD chloride or nitrate or sulfate20 A mixture containing two anions was tested and the results are shown below.test result dilute nitric acid added effervescence of a gas whichturned limewater milkyyellow precipitate formeddilute nitric acid added, followedby aqueous silver nitrateWhich anions were present?A carbonate and chlorideB carbonate and iodideC sulfate and chlorideD sulfate and iodide© UCLES 2011 0620/11/M/J/1121X is a monatomic gas.gas XWhich statement about X is correct?A X burns in air.B X is coloured.C X is unreactive.D X will displace iodine from potassium iodide.22The diagram shows a section of the Periodic Table.I II III IV V VI VII0V XWYZWhich elements will conduct electricity at room temperature?A V, W and XB V, Y and WC W, X and ZD Y and Z23The equation shows the reaction between a halogen and aqueous bromide ions.X2 + 2Br–(aq) → 2X–(aq) + Br2…1… …2… …3…Which words correctly complete gaps 1, 2 and 3?1 2 3A chlorine brown colourlessB chlorine colourless brownC iodine brown colourlessD iodine colourless brown© UCLES 2011 0620/11/M/J/11 [Turn over24Which statement is correct for the element of proton number 19?A It is a gas that dissolves in water.B It is a hard metal that is not very reactive with water.C It is a non-metal that burns quickly in air.D It is a soft metal that is highly reactive with water.25Brass is an alloy of copper and zinc.Which statement is correct?A Brass can be represented by a chemical formula.B Brass is formed by a chemical reaction between copper and zinc.C The alloy will dissolve completely in dilute hydrochloric acid.D The zinc in the alloy will dissolve in dilute hydrochloric acid.26Which substance is a metal?electrical conductivity(solid) electrical conductivity(molten)A high highB high lowC low highD low low27The table shows the results of adding three metals, P, Q and R, to dilute hydrochloric acid and to water.metal dilute hydrochloric acid waterP hydrogen produced hydrogen producedQ no reaction no reactionR hydrogen produced no reactionWhat is the order of reactivity of the metals?mostreactive least reactiveA P R QB P Q RC R Q PD R P Q© UCLES 2011 0620/11/M/J/1128The properties of a metal are important in deciding its use.Which row lists a property that is not correct for the use given?use of the metal metal property neededA aluminium in aircraft wings low densityB aluminium in food containers resists corrosionC mild steel in car bodies high densityD stainless steel in cutlery does not rust29Wh ich row describes th e conditions used to make steel from th e iron produced by a blast furnace?calcium oxide(lime) oxygenh eatABCD30Water from a reservoir flows to th e water works wh ere purification processes 1 takes place followed by process 2.What are purification processes 1 and 2?purification process 1 purification process 2A ch lorination filtration B filtration ch lorinationC fractional distillation filtrationD filtration fractionaldistillation31The diagram shows the composition by volume of air.XWhat is X?A argonB carbon dioxideC nitrogenD oxygen32The table gives the composition of the atmosphere of four newly discovered planets.planet composition of atmosphereW argon, carbon dioxide and oxygenX argon, nitrogen and oxygenY argon, carbon dioxide and methaneZ methane, nitrogen and oxygen On which planets is the greenhouse effect likely to occur?A W onlyB W, X and ZC W and Y onlyD W, Y and Z33Statement 1: Alloying iron with other materials to form stainless steel prevents iron from rusting by excluding oxygen.Statement 2: Painting, oiling and electroplating are all methods of preventing iron from rusting.Which is correct?A Both statements are correct and statement 2 explains statement 1.B Both statements are correct but statement 2 does not explain statement 1.C Statement 1 is correct but statement 2 is incorrect.D Statement 2 is correct but statement 1 is incorrect.34Wh ich two substances, wh en reacted togeth er, would form a salt th at contains two of th e essential elements provided by fertilisers?A potassium hydroxide and nitric acidB potassium hydroxide and sulfuric acidC sodium hydroxide and nitric acidD sodium hydroxide and sulfuric acid35Greenhouse gases may contribute to climate change.Two of these gases are emitted into the atmosphere as a result of processes within animals.Gas ……1…… is produced by process ……3…… .Gas ……2…… is produced by process ……4…… .Which words correctly complete gaps 1, 2, 3 and 4?1 2 3 4A CO C2H6 digestion respirationB CO C2H6 respiration digestionC CO2 CH4 digestion respirationD CO2 CH4 respiration digestion36 Compounds containing five carbon atoms in a molecule may have names beginning with ‘pent…’.What is the name of the compound shown?key= carbon = oxygen= hydrogenA pentaneB pentanoic acidC pentanolD pentene37 Which industrial process is shown in the diagram?crude oil vapourA crackingB fermentationC fractional distillationD polymerisation38The diagram shows the structures of three compounds.OCH HOHCH HCHHHHOC CHHC HWhy do these three compounds belong to the same homologous series?A They all contain carbon, hydrogen and oxygen.B They all contain the same functional group.C They are all carbon based molecules.D They are all flammable liquids.39What is the main constituent of natural gas?A carbon dio x ideB ethaneC hydrogenD methane40 What is not essential for the formation of ethanol by fermentation?A lightB sugarC yeastD water16Per mission to r epr oduce items wher e thir d-par ty owned mater ial pr otected by copyr ight is included has been sought and clear ed wher e possible. Ever y reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.G r o u p140C eC e r i u m 58141P rP r a s e o d y m i u m 59144N d N e o d y m i u m 60P mP r o m e t h i u m61150S mS a m a r i u m62152E uE u r o p i u m63157G dG a d o l i n i u m64159T bT e r b i u m65162D yD y s p r o s i u m66165H oH o l m i u m67167E rE r b i u m68169T mT h u l i u m69173Y bY t t e r b i u m70175L uL u t e t i u m71232T hT h o r i u m 90P aP r o t a c t i n i u m 91238UU r a n i u m92N pN e p t u n i u m93P uP l u t o n i u m94A mA m e r i c i u m95C mC u r i u m96B kB e r k e l i u m97C fC a l i f o r n i u m98E sE i n s t e i n i u m99F mF e r m i u m100M dM e n d e l e v i u m101N oN o b e l i u m102L rL a w r e n c i u m1031HH y d r o g e n17L iL i t h i u m 323N aS o d i u m 1124M gM a g n e s i u m1240C aC a l c i u m 2045S c S c a n d i u m 2148T i T i t a n i u m2251V V a n a d i u m 2352C r C h r o m i u m 2455M n M a n g a n e s e 2556F e I r o n 2659C o C o b a l t 2759N i N i c k e l 2864C u C o p p e r 2965Z n Z i n c3070G aG a l l i u m3127A l A l u m i n i u m1311B B o r o n 512C C a r b o n614NN i t r o g e n716OO x y g e n819FF l u o r i n e928S iS i l i c o n1431PP h o s p h o r u s1532SS u l f u r1635.5C lC h l o r i n e1740A rA r g o n1820N eN e o n104H eH e l i u m273G eG e r m a n i u m3275A sA r s e n i c3379S eS e l e n i u m3480B rB r o m i n e3584K rK r y p t o n3639KP o t a s s i u m 1988S rS t r o n t i u m 3889Y Y t t r i u m 3991Z r Z i r c o n i u m4093N b N i o b i u m 4196M o M o l y b d e n u m 42T c T e c h n e t i u m 43101R u R u t h e n i u m 44103R h R h o d i u m 45106P d P a l l a d i u m 46108A g S i l v e r47112C dC a d m i u m48115I nI n d i u m49119S nT i n50122S bA n t i m o n y51128T eT e l l u r i u m52127II o d i n e53131X eX e n o n54137B aB a r i u m 56139L a L a n t h a n u m 57*178H fH a f n i u m72181T a T a n t a l u m 73184W T u n g s t e n 74186R e R h e n i u m 75190O s O s m i u m 76192I rI r i d i u m 77195P t P l a t i n u m78197A uG o l d79201H gM e r c u r y80204T lT h a l l i u m81207P bL e a d82209B iB i s m u t h83P oP o l o n i u m84A tA s t a t i n e85R nR a d o n86F rF r a n c i u m 87227A cA c t i n i u m899B eB e r y l l i u m4II I I I II V V V I V I I 085R bR u b i d i u m 37133C sC a e s i u m 55226R a R a d i u m 88T h e v o l u m e o f o n e m o l e o f a n y g a s i s 24d m 3a t r o o m t e m p e r a t u r e a n d p r e s s u r e (r .t .p .).a Xb a = r e l a t i v e a t o m ic m a s sX = a t o m i c s y m b o lb = p r o t o n (a t o m ic ) n u m b e rK e y *58-71 L a n t h a n o i d s e r i e s 90-103 A c t i n o i d s e r i e s D A T A S H E E T T h e P e r i o d i c T a b l e o f t h e E l e m e n t s。
IGCSE化学真题答案paper62017
IGCSE化学真题答案paper620171、以橙皮苷为指标成分进行定性鉴别的中药是（）[单选题] *A葛根B黄芩C槐花D陈皮(正确答案)2、萜类化合物在化学结构上的明显区别是（）[单选题] *A氮原子数不同B碳原子数不同(正确答案)C碳环数不同D硫原子数不同3、E连续回流提取法(正确答案)下列方法中能始终保持良好浓度差的是（）* A浸渍法B渗漉法(正确答案)C煎煮法D回流提取法4、E何首乌生物碱沉淀反应的条件是（）[单选题] *A酸性水溶液(正确答案)B碱性水溶液C中性水溶液D盐水溶液5、挥发油可析出结晶的温度是（）[单选题] *A0～-20℃(正确答案)B0～10℃C0～20℃D0～15℃6、阿托品是莨菪碱的（）[单选题] *A左旋体B右旋体C同分异构体D外消旋体(正确答案)7、单萜和倍半萜在化学结构上的明显区别是（）[单选题] * A氮原子数不同B碳原子数不同(正确答案)C碳环数不同D硫原子数不同8、具有挥发性的生物碱是（）[单选题] *A吗啡碱B麻黄碱(正确答案)C苦参碱D小檗碱9、黄酮母核具有的下列何种结构特点在碱液中不稳定（）[单选题] *A邻二酚羟基(正确答案)B3-羟基C5-羟基D7-羟基10、苯丙素类的基本母核是具有一个或数个（）单元的天然化合物（）[单选题] * AC6-C3基团(正确答案)BC6-C6基团CC5-C3基团DC8-C8基团11、下列化合物可用水蒸汽蒸馏法提取的是（）[单选题] * A七叶内酯(正确答案)B七叶苷C厚朴酚D五味子素12、以下不属于吸附色谱法的操作步骤的是（）[单选题] * A制板B洗脱(正确答案)C点样D显色13、下列化合物中，酸性最强的是（）[单选题] *A芦荟大黄素B大黄酚C大黄素甲醚D大黄酸(正确答案)14、很少含有挥发油的植物科为（）[单选题] *A菊科B唇形科C茜草科(正确答案)D姜科15、分馏法分离挥发油的主要依据是（）[单选题] *A密度的差异B沸点的差异(正确答案)C溶解性的差异D旋光性的差异16、碱水提取芦丁时，若PH过高会使（）[单选题] *A产品质量降低B产品收率降低(正确答案)C苷键水解断裂D内酯环开环17、从香豆素类的结构与分类看，下列属于简单香豆素类的是（）[单选题] * A龙脑B七叶内酯(正确答案)C薄荷醇D西瑞香素18、萃取法是利用混合物中各成分在两相溶剂中的分配.系数不同而到达分离的方法，所谓两相溶剂是指（）[单选题] *A两种相互接触而又不相溶的溶剂(正确答案)B两种不相互接触而又互相溶的溶剂C两种不相互接触而又不相容的溶剂D两种互相接触而又互相溶的溶剂19、适用于队热及化学不稳定的成分、低极性成分的提取（）[单选题] *A渗漉法B超声提取法C回流提取法D超临界流体提取法(正确答案)20、游离木脂素易溶于下列溶剂，除了（）[单选题] *A乙醇B氯仿C乙醚D水(正确答案)21、组成缩合鞣质的基本单元是（）[单选题] *A黄烷-3-醇(正确答案)B酚羟基C环戊烷D哌啶环22、下列含有蒽醌类成分的中药是（）*A丹参B决明子(正确答案)C芦荟(正确答案)D紫草23、香豆素衍生物最常见的羟基取代位置是（）[单选题] * AC7位(正确答案)BC5位CC3位DC6位24、水提醇沉法可以沉淀下列（）等成分（）[单选题] *A葡萄糖B多糖(正确答案)C树脂D生物碱25、以黄芩苷、黄芩素、汉黄芩素为指标成分进行定性鉴别的中药是（）[单选题] * A葛根B黄芩(正确答案)C槐花D陈皮26、在简单萃取法中，一般萃取几次即可（）[单选题] *A3～4次(正确答案)B1～2次C4～5次D3～7次27、颜色随pH值不同而变化的是（）[单选题] *A黄酮B花青素(正确答案)C二氢黄酮D查耳酮28、凡具有（）的木脂素，与三氯化铁反应，呈阳性（）[单选题] *A酚羟基(正确答案)B羧酸C醇羟基D氨基29、下列应用最广的经典提取方法是（）[单选题] *A水蒸气蒸馏法B溶剂提取法(正确答案)C超临界流体萃取法D超声提取法30、E连续回流提取法(正确答案)从中药中水提取液中萃取偏于亲水性的成分的溶剂是（）[单选题] *A正丁醇(正确答案)B乙醇C乙醚D三氯甲烷。
igcse化学试题及答案
igcse化学试题及答案IGCSE化学试卷考生须知：1. 请在答题纸的指定位置填写您的姓名、考号和座位号。
2. 所有答案必须写在答题纸上，写在试卷上的任何答案都无效。
3. 考试时间为2小时。
4. 请仔细阅读题目要求，确保您的答案符合题目要求。
一、选择题（每题2分，共20分）1. 下列哪个元素的原子序数为17？A. 氟B. 氯C. 氧D. 氮2. 化学反应中，能量的释放通常表现为：A. 吸热反应B. 放热反应C. 光合作用D. 呼吸作用3. 根据化学计量学，1摩尔物质的质量等于：A. 1克B. 1千克C. 该物质的摩尔质量D. 该物质的原子量4. 以下哪个是酸碱中和反应的典型特征？A. 产生气体B. 产生沉淀C. 产生水D. 产生盐5. 以下哪个是有机化合物？A. 二氧化碳B. 一氧化碳C. 甲烷D. 水...（此处省略其他选择题）二、简答题（每题10分，共30分）1. 解释什么是化学平衡，并给出一个例子。
2. 描述燃烧反应的一般特征，并给出一个具体的例子。
3. 什么是氧化还原反应？请给出一个例子并解释其过程。
三、计算题（每题15分，共30分）1. 如果你有100克的硫酸钠（Na2SO4），请计算其摩尔数。
2. 一个化学反应的初始浓度为0.5摩尔/升的氢氧化钠（NaOH）和0.3摩尔/升的盐酸（HCl）。
如果反应完全进行，计算最终溶液的pH值。
四、实验题（每题20分，共20分）1. 描述如何使用滴定法来确定一个未知酸溶液的浓度。
答案：一、选择题1. B. 氯2. B. 放热反应3. C. 该物质的摩尔质量4. C. 产生水5. C. 甲烷二、简答题1. 化学平衡是指在一个可逆反应中，正向反应和逆向反应进行的速度相等，系统达到一个动态平衡状态，此时各物质的浓度保持不变。
例如，氮气和氢气合成氨的反应。
2. 燃烧反应是氧化反应的一种，其特征是放出大量的热能和光能，通常伴随着气体的产生。
例如，甲烷燃烧生成二氧化碳和水。
igcse2017化学夏卷答案
igcse2017化学夏卷答案1．空气成分中，体积分数最大的是（） [单选题] *A．N2(正确答案)B．O2C．CO2D．稀有气体2．下列属于化学变化的是（） [单选题] *A．冰雪融化B．纸张燃烧(正确答案)C．水分蒸发D．矿石粉碎答案解析：有新物质生成的是化学变化。
燃烧有新物质生成。
3．温泉水富含钾、钠、钙、镁、锌等矿物质，这里的“钾、钠、钙、镁、锌”指的是（） [单选题] *A．元素(正确答案)B．原子C．单质D．分子答案解析：是指，指的是就选元素。
4．废弃的易拉罐和塑料瓶属于（） [单选题] *A．厨余垃圾B．其他垃圾C．可回收物(正确答案)D．有害垃圾5．能闻到花香的原因是（） [单选题] *A．分子的质量很小B．分子间有间隔C．分子在不断运动(正确答案)D．分子由原子构成6．下列物质在氧气中燃烧，产生大量白烟的是（） [单选题] * A．木炭B．甲烷C．蜡烛D．红磷(正确答案)答案解析：红磷燃烧的现象是黄焰白烟。
7．碳酸氢钠常用于焙制糕点，其俗称是（） [单选题] * A．熟石灰B．小苏打(正确答案)C．烧碱D．纯碱8．下列物质的用途中，利用其物理性质的是（） [单选题] *A．干冰用作冷冻剂(正确答案)B．甲烷用作燃料C．氧气用于炼钢D．硫酸用于处理碱性废液答案解析：干冰用作冷冻剂，是干冰易升华。
干冰升华是状态的改变，没有新物质生成。
9．下列属于氧化物的是（） [单选题] *A．O2B．SO2(正确答案)C．K2CO3D．NaOH答案解析：氧化物是由两种元素组成，其中一种元素是氧元素。
10．下列原子中的粒子，带负电荷的是（） [单选题] *A．电子(正确答案)B．中子C．质子D．原子核答案解析：电子带负电。
11．下列属于纯净物的是（） [单选题] *A．加碘食盐B．氧气(正确答案)D．食醋答案解析：纯净物是由一种物质组成。
并且纯净物可以写出化学式。
12．下列实验操作正确的是（）[单选题] * A．点燃酒精灯B．倾倒液体C．称量食盐(正确答案)D．加热液体13．下列气体能使紫色石蕊溶液变红的是（） [单选题] *A．CO2(正确答案)B．O2C．H2D．N2答案解析：二氧化碳与水反应产生碳酸，碳酸可以使紫色石蕊溶液变红。
2020-2021学年北京国际学校高三化学下学期期末试题含解析
2020-2021学年北京国际学校高三化学下学期期末试题含解析一、单选题（本大题共15个小题，每小题4分。
在每小题给出的四个选项中，只有一项符合题目要求，共60分。
）1. 下列各组说法均不正确的是① CH3—CH=CH2和CH2=CH2的最简式相同② CH≡CH和C6H6含碳量相同③正戊烷、异戊烷、新戊烷的沸点逐渐变低④丁二烯和丁烯为同系物⑤标准状况下，11.2 L的戊烷所含的分子数为0.5 N A（N A为阿伏加德罗常数）⑥能够快速、微量、精确的测定相对分子质量的物理方法是核磁共振氢谱法A．①②⑥ B．②③④ C．②③⑥ D．④⑤⑥参考答案：D略2. 随着科技的飞速发展，出现了许多新型无机材料，如植入生物体内的生物陶瓷材料HAP[化学式为Cam(P04)n(OH)2]，已被医疗上用于修补人的骨骼和牙组织，HAP的化学式中m等于（）A． B． C． D．参考答案：A略3. 北京2008奥运会金牌为金镶玉，直径为70mm.厚6mm。
某化学兴趣小组对金牌中金属的成分提出猜想：甲认为该金属是由纯金制成；乙认为该金属是由金银合金制成；丙认为该金属是由黄铜（铜锌合金）制成。
为了验证他们的猜想，取制造这种金牌的材质粉末少量进行实验，加入下面一种试剂来证明甲、乙、丙猜想的正误，该试剂应是A.硫酸铜溶液B.盐酸C.稀硝酸D.硝酸银溶液参考答案：C4. 下列推断或表述正确的是（）A．25°时，有pH=a的醋酸溶液，将此溶液稀释1倍后，溶液的pH=b，则a＞bB．向2.0mL浓度均为0.1mol?L﹣1的KCl、KI混合液滴加1～2滴0.01 mol?L﹣1AgNO3溶液，振荡，沉淀呈黄色，说明AgCl的Ksp比AgI的Ksp小C．0.2mol/L的一元酸HX与0.1mol/L的KOH溶液等体积混合所得溶液中，一定有：c（H+）+c（K+）═c（OH﹣）+c（X﹣）D．25°时，0.2mol?L﹣1盐酸与等体积0.05mol?L﹣1Ba（OH）2溶液混合后，溶液pH为1参考答案：C考点：弱电解质在水溶液中的电离平衡；难溶电解质的溶解平衡及沉淀转化的本质．.专题：电离平衡与溶液的pH专题．分析：A．加水稀释醋酸中的氢离子浓度减小；B．沉淀呈黄色，说明AgI溶解度较小；C．根据电荷守恒分析；D．0.2mol?L﹣1盐酸与等体积0.05mol?L﹣1Ba（OH）2溶液混合后酸过量，计算剩余的H+离子浓度．解答：解：A．25°时，有pH=a的醋酸溶液，将此溶液稀释1倍后，醋酸中的氢离子浓度减小，pH增大，所以a＜b，故A错误；B．沉淀呈黄色，说明AgI先析出，则AgI溶解度较小，则AgCl的K sp比AgI的K sp大，故B错误；C．0.2mol/L的一元酸HX与0.1mol/L的KOH溶液等体积混合所得溶液中，溶液中存在电荷守恒，即正电荷的总浓度等于负电荷的总浓度，则有：c（H+）+c（K+）═c（OH﹣）+c（X﹣），故C正确；D．0.2mol?L﹣1盐酸与等体积0.05mol?L﹣1Ba（OH）2溶液混合后酸过量，c（H+）==0.05mol/L，则pH不为1，故D错误．故选：C．点评：本题考查电解质在水中的电离、溶度积常数电荷守恒的应用等，明确稀释及混合时溶液中离子浓度的变化及计算即可解答，题目难度不大．5. 下列有关物质的性质和应用均正确的是A．NH3能氧化氮氧化物，可用于汽车尾气净化B．瓷坩埚能耐高温，可用于加热分解石灰石C．Fe在O2中的燃烧产物可用于制红色涂料D．Mg (OH)2分解吸热且生成高熔点固体，可用作阻燃剂参考答案：D略6. 一定条件下反应一段时间后，测得密闭容器内M、N、P、Q四种物质各物质的质量：下列说法正确的是A．该反应类型属置换反应 B．物质P一定是化合物C．反应生成的N与Q的质量比为7:3 D．M肯定为该反应的催化剂参考答案：B略7. 醋酸溶液中存在电离平衡：CH3COOH(aq)H＋＋CH3COO－，下列叙述不正确的是A．CH3COOH溶液中离子浓度的关系满足：c(H＋)＝c(OH－)＋c(CH3COO－)B．0.1 mol/L的CH3COOH溶液加水稀释，溶液中c(OH－)减小C．CH3COOH溶液中加入少量CH3COONa固体，平衡逆向移动D．常温下，pH＝2的CH3COOH溶液与pH＝12的NaOH溶液等体积混合后，溶液的pH<7 参考答案：B略8. 下列反应中，氧化剂与还原剂物质的量关系为1∶2的是A．O3＋2KI＋H2O===2KOH＋I2＋O2B．2CH3COOH＋Ca(ClO)2===2HClO＋Ca(CH3COO)2C．I2＋2NaClO3===2NaIO3＋Cl2D．4HCl(浓)＋MnO2MnCl2＋Cl2↑＋2H2O参考答案：AD略9. 已知t℃时，某物质的不饱和溶液ag含溶质mg若溶液蒸发bg水，并恢复到t℃时析出不含结晶水的溶质ng 。
2024年高中化学会考试题与解答英文版
2024年高中化学会考试题与解答英文版2024 High School Chemistry Achievement Test Questions and AnswersSection 1: Multiple Choice1. Which of the following elements is a noble gas?A. HydrogenB. OxygenC. NeonD. CarbonAnswer: C. Neon2. What is the chemical symbol for iron?A. FeB. IrC. InD. IoAnswer: A. Fe3. What is the pH of a solution that is considered neutral?A. 7B. 10C. 2D. 5Answer: A. 7Section 2: Short Answer4. Define a chemical reaction and provide an example.Answer: A chemical reaction is a process that involves the breaking and formation of chemical bonds between different substances. An example is the reaction between hydrogen and oxygen to form water.5. Describe the difference between an exothermic and endothermic reaction.Answer: An exothermic reaction releases energy in the form of heat, while an endothermic reaction absorbs energy from its surroundings.Section 3: Problem Solving6. Calculate the molarity of a solution containing 0.5 moles of solute dissolved in 2 liters of solvent.Answer: Molarity = moles of solute / liters of solutionMolarity = 0.5 moles / 2 litersMolarity = 0.25 M7. Balance the following chemical equation:C3H8 + O2 -> CO2 + H2OAnswer:C3H8 + 5O2 -> 3CO2 + 4H2OSection 4: Essay8. Discuss the importance of the periodic table in understanding the properties of elements and predicting chemical reactions.Answer: The periodic table is a fundamental tool in chemistry that organizes elements based on their atomic number and properties. By analyzing the periodic trends, such as atomic radius and electronegativity, chemists can predict how elements will behave in chemical reactions. This knowledge is crucial in designing new compounds and understanding the behavior of matter at the atomic level.。
2021年高二下学期4月月考化学试题(国际班) 含答案
2021年高二下学期4月月考化学试题（国际班）含答案说明：本试题分第Ⅰ卷（选择题）和第П卷（非选择题），考试时间为90分钟，卷面总分为100分，第Ⅰ卷涂在答题卡上，考试完毕后，上交第П卷和答题卡。
可能用到的相对原子质量：H:1 O:16 C:12 N:14 Na:23 S:32 Al:27 Ca:40第Ⅰ卷选择题（共80分）1．下列说法不正确．．．的是( )A．明矾可做消毒剂B．次氯酸钠可作漂白剂C．氧化铝可作耐火材料D．氢氧化铝可作治疗胃酸过多的药物2．化学与日常生活密切相关，下列说法错误．．的是( )A．Al2O3可用作高温耐火材料B．利用漂白粉的氧化性漂白织物C．浓硫酸可刻蚀石英制艺术品D．在医疗上碳酸氢钠可用于治疗胃酸过多3．下列铁的化合物不可能由化合反应直接制得的是( )A．FeCl2 B．Fe2(SO4)3 C．FeCl3 D．FeS4．某溶液中滴入KSCN溶液后变红，说明该溶液中存在A．NO3－ B．Fe3+ C．SO42－ D．Mg2+5．（xx秋•曲沃县校级期末）下列有关化学物质的俗称错误的是( )A．碳酸钠的俗称是纯碱 B．四氧化三铁的俗称是磁性氧化铁C．氧化铁的俗称是铁红 D．碳酸氢钠的俗称是苏打6．合金是一类用途广泛的金属材料。
下列物质中，不属于合金的是( )A．碳素钢 B．黄铜 C．硬铝 D．水银7．目前用量最大，用途最广的合金是( )A．钢铁 B．塑料 C．铝合金 D．青铜8．关于合金的叙述，不正确的是( )A．合金的熔沸点比原任一金属要高 B．合金的硬度比原任一金属要大C．非金属也可以是合金的成分之一 D．合金的用途比纯金属的用途更广9．4G网络让手机费起来了。
手机芯片的核心是硅板，其成分是( )A．SiO2 B．Si C．H2Si03 D．Na2SiO310．下列物质中用于制造光导纤维的材料是( )A．铜合金 B．陶瓷 C．聚乙烯 D．二氧化硅11．下列物质为纯净物的是( )A．水泥 B．水玻璃 C．氨水 D．液氯12．漂白粉的有效成分是( )A．次氯酸钙 B．氯化钙 C．次氯酸 D．次氯酸钙与氯化钙13．下列物质的用途与其性质的对应关系错误的是( )A．氯气用于自来水消毒﹣次氯酸的强氧化性B．碘化银用于人工降雨﹣使空气中水蒸汽凝聚C．氢氟酸腐蚀玻璃﹣强酸性D．过氧化钠用于做供氧剂﹣能与CO2、H2O反应生成氧气14．下列物质不能使有色布条褪色的是( )A．氯水 B．次氯酸钠溶液 C．氯化钙溶液 D．漂白粉溶液15．区别NaCl、FeCl3和NH4Cl三种溶液，可选用下列试剂中的( )A．KSCN溶液 B．NaOH溶液 C．AgNO3溶液 D．BaCl2溶液16．下列气体有颜色并有刺激性气味的是( )A． CO B．Cl2 C．N2 D．CO217．空气污染是人类社会面临的重大威胁。
吉林省名校联盟2024-2025学年高三上学期教学质量检测化学试题(含解析)
高三化学试卷本试卷满分100分，考试用时75分钟。
注意事项：1．答题前，考生务必将自己的姓名、考生号、考场号、座位号填写在答题卡上。
2．回答选择题时，选出每小题答案后，用铅笔把答题卡上对应题目的答案标号涂黑。
如需改动，用橡皮擦干净后，再选涂其他答案标号。
回答非选择题时，将答案写在答题卡上。
写在本试卷上无效。
3．考试结束后，将本试卷和答题卡一并交回。
4．可能用到的相对原子质量：H 1 N 14 O 16 Na 23 Mg 24 S 32 Fe 56 Cu 64一、选择题：本题共15小题，每小题3分，共45分。
在每小题给出的四个选项中，只有一项是符合题目要求的。
1．每一种生肖都有其独特的文化内涵。
下列与生肖有关的文物中，主要材质为金属材料的是（）A ．错金杜虎符B ．龙形玉佩C ．瓷猪（宋）D ．陶鸡2．化学与生活密切相关，下列不涉及化学变化的是（ ）A ．炒菜的锅未洗净出现锈斑B ．打磨磁石制作指南针C ．炖排骨汤时加点醋，味道更鲜D ．切开的茄子放置后切面变色3．中华文化源远流长，化学与文化传承密不可分。
下列说法正确的是（ ）A ．“曾青涂铁，铁赤色如铜”，涉及的反应能证明氧化性：B ．“绿蚁新醅酒，红泥小火炉”，制作火炉的“红泥”中含氧化铁C ．古陶瓷修复时所用的熟石膏，其成分为D ．“九秋风露越窑开，夺得千峰翠色来”，“翠色”是因为成分中含有氧化亚铜4．幸福不会从天而降，美好生活靠劳动创造。
下列劳动项目与所述的化学知识没有关联的是（ ）选项劳动项目化学知识A 医院消毒：喷洒次氯酸钠溶液次氯酸钠溶液显碱性B 生产活动：海水晒盐蒸发原理C 家务劳动：用食醋洗水壶醋酸可与水垢中的、反应D工业生产：技术人员开发高端耐腐蚀镀铝钢板铝能形成致密氧化膜5．下列分散系不能产生丁达尔效应的是（）32FeCu ++>()2Ca OH ()2Mg OH 3CaCOA ．有色玻璃B ．硫酸铜溶液C ．氢氧化铁胶体D ．蛋白质溶液6．茶叶中铁元素的检验可经过以下四步完成：①干茶叶灼烧灰化；②将茶叶灰用溶液溶解；③过滤，得澄清溶液；④滴加试剂检测滤液中的铁元素。