问题 计算题

(5分)现有两种稀溶液:标记为A的0.0400%的氢氧化钠溶液;标记为B的0.365%的盐酸。假设本题所涉及到的各种稀溶液的密度均近似为1.00g·mL-1,且每滴溶液的体积近似为0. 05mL,试解答下列各小题。

(1)恰好完全中和20. 0gA溶液,需加入B溶液多少克?

(2)在盛有20. 0mLA溶液的锥形瓶中滴加2滴酚酞试液,再向瓶中缓缓倒人10. 0mLB溶液,边倒边振荡,充分混合后溶液呈无色。若取该无色混合液3.00mL于一支试管内,再向试管内滴加1滴A溶液,试通过计算说明此时试管内溶液呈现的颜色。

答案

(1)2.00g; (2)溶液显无色

题目分析:已知量:氢氧化钠:20.0g×0.0400%=0.008g; 0.365%的盐酸;10. 0mLB溶液中氯化氢的质量;10. 0mLB溶液;混合液3.00mL;未知量:(l)恰好完全中和20. 0gA溶液,需加入B溶液的质量;(2)试管内溶液的颜色;

解:(1)恰好完全中和20. 0gA溶液,需加入B溶液的质量为x

HCl  +   NaOH==NaCl+H2O

36.5      40

0.365%x   0.008g

=

x=2.00g   

(2)20. 0mL氢氧化钠溶液中含有氢氧化钠质量为8g;因为恰好完全中和20. 0gA溶液,需0.365%的盐酸的质量为2.00g,3mL盐酸中氯化氢的质量为:3mL·30mL-1×8g×0.365%=2.92g×10-3g;

设1滴A溶液中的氢氧化钠能中和1氯化氢的质量为y,

HCl   +    NaOH==NaCl+H2O

36.5         40

y      0.05g×0.04%

=

y-1.825g×10-3g<2.92g×10-3g;

所以盐酸有剩余,溶液显无色。                                                                                        

单项选择题 B型题
阅读理解

Shakespeare ,more perhaps than any other writer ,made full use of the greatest resources of the English Language .Most of us use about five thousand words in our normal employment of English ;Shakespeare in his works used about twenty—five thousand! There is probably no better way for a foreigner to appreciate the richness and variety of the English language than by studying the various ways in which Shakespeare uses it .Such a study is well worth the effort, even though some aspects of English usage ,and the meaning of many words ,have changed since Shakespeare’s day.

However ,it is surprising that we should know comparatively little about the life of the greatest English author. We know that Shakespeare was born in 1564 in Stratford—on—Avon ,and that he died there in 1616.He almost certainly attended the Grammer School in the town ,but of this we cannot be sure .We know he was married there in 1582 to Anne Hathaway and that he had three children .We know that he spent much of his life in London writing his masterpieces .But this is almost all that we do know .

However ,what is important about Shakespeare’s life is not its incidental details but its products , the plays and the poems .For many years scholars have been trying to add a few facts about Shakespeare’s life to the small number we already possess and for an equally long tine critics(批评)have been theorizing(理论化)about the plays .Sometimes ,indeed ,it seems that the poetry of Shakespeare will disappear under the great mass of comment that has been written upon it .

Fortunately this is not likely to happen .Shakespeare’s people have long delighted not just the English but lovers of literature everywhere ,and will continue to do so after the scholars and critics and all their works have been forgotten.

51.This passage is about         .

A.the great length of each chapter

B.the great varieties in writing styles

C.the richness of the content in Shakespeare’s works

D.the rich English language used by Shakespeare in his works

52.According to the writer ,which of the following remains uncertain about Shakespeare?

A.His date of birth.

B.His marriage.

C.His life in the Grammer School.

D.His date of death.

53.It can be inferred from Para 3 that           .

A.not all the comments on Shakespeare’s works have produced good effects

B.scholars have successfully collected facts about Shakespeare’s life

C.critics are more interested in Shakespeare’s play than his poetry

D.the details of Shakespeare’s life are more important than his literary works

54.What does the last sentence in Para 3 mean ?

A.People don’t think the poetry of Shakespeare good any more.

B.People pay more attention to the comment than the poetry of Shakespeare.

C.People can’t see the poetry of Shakespeare any more.

D.The comment is printed on the poetry of Shakespeare.

55.“Shakespeare’s people” in Para 4refers to             .

A.the characters in Shakespeare’s products

B.the people whose native language is English

C.the people living in Shakespeare’s day

D.the readers of Shakespeare’s works