问题 选择题

某温度下,体积一定的密闭容器中进行如下可逆反应:X(g)+Y(g)⇌Z(g)+W(s);△H>0

下列叙述正确的是(  )

A.加入少量W,逆反应速率增大

B.当容器中气体压强不变时,反应达到平衡

C.升高温度,平衡逆向移动

D.平衡后加入X,上述反应的△H增大

答案

A、W在反应中是固体,固体量的增减不会引起化学反应速率的改变和化学平衡的移动,故A错误;

B、随反应进行,气体的物质的量减小,压强减小,压强不变说明到达平衡,说明可逆反应到达平衡状态,故B正确;

C、该反应正反应为吸热反应,升高温度平衡向吸热反应移动,即向正反应移动,故C错误;

D、反应热△H与物质的化学计量数有关,物质的化学计量数不变,热化学方程式中反应热不变,与参加反应的物质的物质的量无关,故D错误;

故选B.

选择题
阅读理解

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项.选项中有两项为多余选项.

  __1__  

According to figures, some 80 per cent of children with better than expected reading skills had their

own books, compared with just 58 per cent who were below the level expected for their age group.

Children as young as seven are more likely to own a mobile phone than a book, figures show.__2__

  Almost nineinten pupils now have a mobile compared with fewer than threequarters who have their

own books in the home, it was disclosed.The study by the National Literacy Trust suggested a link

between regular access to books outside school and high test scores.__3__  Research led by Nevada

University, in the United States, said that children coming from a "bookish home" remained in education

for around three years longer than young people born into families with empty bookshelves, regardless

of parents' own education, occupation and social class.

  __4__  By ensuring children have access to reading materials in the home and by encouraging children

to love reading, families can help them to do well at school and to enjoy opportunities throughout their

life.

As part of the latest study, the trust surveyed more than 17,000 schoolchildren aged 7 to 16.It found

that 85.5 per cent of pupils had their own mobile phones, compared with 72.6 per cent who had their

own books.Among children in Key Stage 2-aged 7 to 11-79.1 per cent had a mobile compared with

72.7 per cent who had access to books.__5__  

A.It fuels fears over a drop in reading.

B.Family encouragement is essentially important too.

C.Children are more likely to own a mobile phone than a book

D.Reading activities at home has significant positive influences.

E.That could increase children's chances of doing well at school.

F.The findings cause concerns over the effect of modern technology on young people.

G.Children from richer home literacy environments show higher levels of reading knowledge.