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食醋分为酿造醋和配制醋两种。国家标准规定酿造食醋总酸含量不得低于3.5 g/100 mL。

(1)某研究小组利用滴定分析法测定某品牌食醋中醋酸的含量，下列说法正确的是__________。

a．用NaOH溶液滴定时反应的离子方程式为H++OH-=H2O

b．食醋试样需稀释一定倍数后再进行滴定

c．用NaOH溶液滴定食醋，可使用酚酞或甲基橙作指示剂

d．若测得该品牌食醋的物质的量浓度为0. 75 mol/L，则该食醋的总酸量为4.5 g/100 mL。

(2)研究小组的同学仔细观察了该品牌食醋的标签，发现其中还含有苯甲酸钠作为食品添加剂，他想用资料法验证醋酸与食品添加剂(苯甲酸钠C6H5COONa)不会发生离子互换反应，需查找在一定温度下的醋酸与苯甲酸的____________（填写序号）。

a．pH b．电离度 c．电离常数 d．溶解度

(3)常温下，用0.100 0 mol/L NaOH溶液分别滴定20. 00 mL 0．100 0 mol/L HCl溶液和20. 00 mL

0．100 0 mol/L CH3COOH溶液，得到2条滴定曲线，如下图所示。

①滴定醋酸溶液的曲线是____（填“甲”或“乙”）；滴定曲线中a=____mL；

②E点pH>8的原因用离子方程式表示：________________。

(4)现欲粗略测定一未知浓度的CH3COOH溶液的电离度，应做的实验和所需的试剂（试纸）是____。

a．电解，NaOH溶液 b．蒸馏，Na2CO3溶液 c．酯化反应，石蕊试液 d．中和滴定，pH试纸

答案

(1)bd

(2)e

(3)①乙；20.00；②CH3COO-+H2OCH3COOH+OH-

(4)d

听力题

小题1:Next Friday, Duan Linxi _______ （leave） Baoshan for Sishui．

小题2:I forgot ___________ （tell） him．So he knew nothing about it．

小题3:I try __________ （get） good grades in this English exam．

小题4:My good friend always makes me ___________ （laugh）．

小题5:．He finished ________ （read） before 10:00 yesterday．

小题6:It takes me half an hour _______________ （exercise） every day．

小题7:Eating Dangshen and Huangqi herbs ______（be） also good for this．
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     " I will donate blood as long as I am healthy , that's a citizen's responsibility," said Peter Weber, Swiss by
birth and general manager of Four Seasons Shanghai, ___1____donating blood in a blood collection bus
on Friday morning.
     Despite the heat wave    2   the city, nearly 40 employees of the local leading hotel donated this
precious gift, 400ml of blood each, to     3     in need of transfusion.
        4     last week, the city' s blood centers have been thirsty for healthy blood because the need for
blood   5   in summer when traffic and burn accidents are more   6   . But the number of donors decreases
significantLy(明显减少)   7    the hot weather. During the first half of the year, blood donation increased     8     about 5.5 per cent but the clinical( 医学的) use of blood jumped by 11.2 per cent.
        " Right after we heard that the blood centre was short of healthy blood last week, we sent    9    to
our employees calling them to donate , " said  Stanley  Ng , the  hotel's  human  resources  director.
     "Our staff(共作人员) feel    10   to help the hotel make a contribution to public welfare events. "
     Meanwhile , the  hotel  also  11  leaflets(传单) to 50 nearby office buildings informing and encouraging
their employees   12   the Friday donation effort.
      "I hope my blood will help    13    in need, especially the patients with financial difficulty, " said one
donor.
        " Donating blood is good for others and also good for oneself and family. One day, if I or my family
members need to use blood.we   14   receive such help from others. "
     According to the China Blood Donation Law , blood donors can use blood up to   15   they have
donated within five years free of charge. Their family members can also use the same amount of donated
blood , also free of charge.
     In addition,public education on the   16   of blood donation should be improved and more convenient
procedures adapted.
        " The  arrival  of the  blood  collection bus at our hotel makes giving blood     17     more convenient.  Otherwise, it's quite complicated(复杂的) , with the need to make a trip  to a hospital ( blood collection centre) , " Weber     18   .
      All local residents who are   19    to donate their blood, are invited to contact the city's blood centre
via two blood donation   20   :6219-1114,6275-8257.
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     the number  
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D. because              
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D. the number
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D. importance            
D. really                
D. answered              
D. unwilling            
D. hotlines            

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