除去下表所列物质中含有的杂质，所选试剂及操作方法均正确的是（_爱下问搜题

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问题选择题

除去下表所列物质中含有的杂质，所选试剂及操作方法均正确的是（　　）

选项	物质	杂质	除去杂质所选试剂	操作方法
A	二氧化碳	一氧化碳	氧气	点燃
B	氯化钾	碳酸钾	稀盐酸	蒸发
C	锌	铁	稀硫酸	过滤
D	氧化钙	碳酸钙	稀盐酸	蒸发

A．A

B．B

C．C

D．D

答案

A、二氧化碳中混有一氧化碳，通入氧气点燃的方法不可行，会带入氧气等新的杂质，且一氧化碳量很少，也不易点燃，此项错误．

B、氯化钾中混有碳酸钾，加入稀盐酸后蒸发，可以把碳酸钾除掉，并且不带入新的杂质，此项正确．

C、锌中混有铁用稀硫酸，不可行，因为锌和铁都能和稀硫酸反应，会把原物质除去，此项错误．

D、氧化钙中混有碳酸钙，用稀盐酸不可行，因为二者都能和稀盐酸反应，会把原物质除掉，此项错误．

故选B

问答题

铁块的体积是100cm³，密度是7.8×10³kg/m³，通过计算说明能否用量程的5N的弹簧测力计测出它受到的重力．

完形填空

A man hired a taxi outside the airfield．The cab had a woolen carpet with 36 lace edges．On the glass partition that 37 the driver's seat was a copy of a famous painting．Its windows were all clean．The customer was very much 38 and said to the driver，“I've never seen a nicer 39 ．”“Thank you for your praise．”the driver answered 40 ．
“The car isn't mine，”said the driver．“It belongs to the company．I used to be a 41 of cabs．When they returned，all of them were as 42 as garbage cans with cigarette butts and rubbish 43 here and there．On the seats and door-handles could be found something 44 like peanut sauce or, chewing gum．Why so? I thought if the car itself were very clean the passengers would most 45 be considerate and refrain from littering．”
“So when I got a 46 to be a taxi-driver，I began 47 my idea into practice-to tidy and 48 the car． Now before a new passenger gets on my car，I'd make a cheek and be sure it is in good order．When my car 49 after a day's work，it always remains 50 ．”
When doing a thing，one makes efforts and wants to see the result．To change others，one has to make twice the 51 but get half the result．To change oneself is the other way round-more fruit with less effort．One had better ask oneself why one makes 52 on others much more than on oneself． 53 you take enough care to do as best you can for other people's sake，your efforts will yield results，If you 54 the inner world of your own，examine yourself and wipe out the dust and dirt，instead of fixing your eyes on other people，you will find a cheerful 55 for yourself and create a pleasant environment for others．

C．disappointed

C．certificate

A．suggestions

D．look through