问题 选择题

室温下pH=11的xy两种碱溶液各5mL,分别稀释至500mL,其pH与溶液体积(V)的关系如图所示,下列说法正确的是

A.稀释后x溶液中水的电离程度比y溶液中水电离程度小

B.若xy是一元碱,室温下pH=11的xy两种碱溶液的浓度相同

C.若xy都是弱碱,则a的值一定大于9

D.完全中和xy两溶液时,消耗同浓度稀硫酸的体积Vx)>Vy

答案

答案:C

x线pH下降快,说明碱性:x>y;A:稀释后y的碱性相对强,对水的电离抑制程度相对大,水的电离程度相对小;B:两碱的电离度不同,由c(OH)=c×α可知,两者的浓度不同;C:选项正确;D:其中y碱性相对弱,其电离度小,浓度相对大,同体积的两碱溶液,y消耗酸多。

完形填空

背书填空 ( 每空一词,每空0.5分,共计15分)

小题1:The Olympic ______ is “Faster, Higher, stronger”.

小题2:______ there is a river, there is a city. Perhaps this is not always true, but it is true that many of the world’s greatest cities have been ______ on the banks of a river.

小题3:In the 1984 Olympic Games, Carl Lewis from the USA won four medals in ______ and ______ and became one of the best ______ in the 20th century.

小题4:The Neva River flows ______ the centre of St Petersburg in Russia.

小题5:Following the history-making ______ in the 2000 Sydney Olympic Games, China won another______ in 2001 which was not for medal.

小题6:When asked about the ______ of his success, Steven Spielberg said that he ______ much of his success and happiness ______ his wife and children.

小题7:If we know more about what causes endangerment, we may be able to ______ ______ before it is too late.

小题8:Cellphones, or ______ phones, make it possible for us to talk to anyone from anywhere.

小题9:If the new species is too strong or uses too much of the ______ in the habitat, some of the ______ species may become endangered.

小题10:The latest cellphones have ______ such as games, music and an electronic calendar that will ______ you about appointments and important dates.

小题11:People who go to a ______ Western dinner party for the first time may surprised by table ______ in Western culture. Knowing them will help you make a good ______.

小题12:They are all used to their ______: that is, they have learnt how to live successfully in their habitat. When the habitat of a species is changed or _______ , the animal or plant has to either ______ to the change or find a new home.

小题13:Chuck learns that we need friends to share ______ and ______, and that it is important to have someone to care about.

小题14:The knife and fork that are ______ to your plate are a little bit bigger than the ones beside them.

小题15:In 1776 America became an ______ country. After that, the ______ slowly began to change.

单项选择题 A1/A2型题