问题 选择题

下列说法正确的是(  )

A.在0.1mol•L-1Na2CO3溶液中,加两滴酚酞显浅红色,微热后红色加深,说明盐类水解反应是吸热反应

B.已知MgCO3的Ksp=6.82×l0-6,则在含有固体MgCO3的MgCl2、Na2CO3溶液中,都有c(Mg2+)=c(CO32-),且c(Mg2+)•c(CO32-)=6.82×10-6mol2•L-2

C.等体积、pH都为3的酸HA和HB分别与足量的锌反应,HA放出的氢气多,说明酸性:HA>HB

D.已知:

共价键C-CC=CC-HH-H
键能/kJ•mol-1348610413436
上表数据可以计算出(g)+3H2(g)→(g)的△H

答案

A.滴有酚酞的Na2CO3溶液显示红色,是由于碳酸钠溶液中的碳酸根离子水解溶液呈碱性,其中碳酸根离子水解程度受温度的影响,微热,溶液颜色逐渐变深,说明温度高,水解程度大,碱性增强,所以盐类水解是吸热反应,故A正确;

B.含有固体MgCO3的MgCl2、Na2CO3溶液中,c(Mg2+)不一定等于c(CO32-),但c(Mg2+)•c(CO32-)=6.82×10-6 mol2•L-2,故B错误;

C.当体积、pH都为3的酸HA和HB分别与足量的锌反应,HA放出的氢气多,说明HA的物质的量大于HB的物质的量,溶液的体积相等,HA的物质的量浓度大于HB的,所以说明酸性:HA<HB,故C错误;

D.因为苯环中的碳碳键是介于单双键之间的一种独特的键,不存在典型的碳碳双键和碳碳单键,不能用以上表中进行计算,故D错误;

故选:A.

阅读理解

Who says constant texting is just a bad habit? The teenager with the fastest thumbs in the country was crowned on Wednesday at the LG US National Texting Championship in New York City, winning $50,000 after a series of fierce texting battles.

16-year-old Austin Wiershke comes from Rhinelander, Wisconsin of the United States. He took home the top prize at the fifth annual texting event, beating 11 other competitors in the final, including last year’s champion Brianna Hendrickson from Brooklyn, New York.

Wiershke, who was wearing a gray shirt and having Justin Bieber’s hairstyle, sailed through each level of the competition by typing passages of text on a QWERTY keyboard rapidly without any mistaken. One special round even included being blindfolded(蒙眼) on the state to make up phrases by memory.

“I’m extremely nervous,” Wiershke said while waiting for the results after the final round. “I’m getting ready to hear Brianna’s name. When I heard my name was announced, I really couldn’t believe my ears.” After the announcement was made, confetti(五彩纸屑) dropped from the ceiling and Wiershke was met on the stage by the singer who said that she liked texting very much. She was Ashley Tisdale, a famous and beautiful singer, who awarded him his check.

In August, a film on Music Television called “Thumbs” took a behind-the –scenes look at the teenager’s life. It shows how he practiced texting to be the fastest. The film followed a series of young texting competitors, including Brianna Hendrickson, in the weeks leading up to this year’s LG US National Texting Championship. Besides showing the always –connected lifestyle of these teenagers nationwide, the mover also shows the studies, sports , dreams and friendships among these competitors.

小题1:What is the main idea of this passage?

A.A teenager receiver $50,000.

B.Teenagers in the US make money by texting.

C.A teenager was named the fastest texter in the US.

D.The LG US National Texting Championship was held in New York City.小题2: During the special round, competitors were required to text_____________.

A.among confetti

B.without using their eyes

C.using a special keyboard

D.extremely difficult words小题3:We can infer that Austin Wiershke_________.

A.wasn’t used to using the QWERTY keyboard

B.didn’t think Brianna Hendrickson would win this time

C.didn’t expect he would beat Brianna Hendrickson

D.was very confident when he was waiting for the result of the contest小题4:Through the film called “Thumb”, people can know____________.

A.the development of the LG US National Texting Championship

B.various parts of the competitors’ life

C.what happened to the competitors after the contest

D.the details of the texting contest

单项选择题