问题 多选题

对于一定量的气体,若忽略气体分子势能,可能发生的过程是(  )

A.吸收热景,内能减少

B.放出热量,压强不变

C.绝热压缩,内能不变

D.等温吸热,体积不变

答案

A、根据热力学第一定律△U=W+Q可知若气体吸收热量的同时体积膨胀对外做功,且对外做功大于吸收热量,则内能将会减小,故A正确;

B、根据气态方程

PV
T
=C(常数)可知气体压强的变化由V和T的变化决定,而气体放出热量,其温度和体积的变化无法确定,如可能出现温度和体积都增大或都减小,则可以保持压强不变的情况,故B正确;

C、绝热说明气体不能吸放热即Q=0,压缩说明外界对气体做功,根据热力学第一定律△U=W+Q可知:绝热压缩,内能增大,故C错误;

D、等温说明内能不变,即△U=0,吸收热量,即Q>0,根据热力学第一定律△U=W+Q可知W<0,即气体膨胀对外做功,所以等温吸热,体积膨胀,故D错误.

故选AB.

阅读理解

Pubs are an important part of British life. Pubs, formally public houses, are common in towns and villages in England.People usually talk,eat, drink,meet their friends and relax there.You can order soft drinks like orange juice,cola or coffee ,but many people go to pubs to have an alcoholic drink.Many types of alcoholic drinks are available, but the most popular drink is beer.

Traditional English beer comes in a variety of local flavors and is called ‘draught’beer .All draught beer is served from a hand pump on the bar rather than in bottles or cans. Unlike American or other European beers, it is served cool but not cold.Nowadays,a lot of English people enjoy a European beers called lager(淡味啤酒).This is lighter, more refreshing(清新的) and is served cold. Beer is sold in pint or half-pint glasses (a pint is just over half a litre).When you order a drink, ask for a ‘pint’ or a ‘half’ of the beer you want to try.

There is no waiter service in an English pub.You go to the bar and place your order to the pub staff. They will pour your drinks and pass them to you. They will then tell you how much to pay.You have to pay your drinks there and then. After receiving your change,you can carry your drinks back to a table to enjoy. It is usual for friends to take turns buying drinks for each other.This is known as’buying a round’.

Pubs sell cheap food too.The choice of food ranges(涉及) from small bar snacks such as crisps and peanuts ,to three-course meals.A popular meal during the summer months is a ‘ploughman’s  lunch ’.This is a dish of bread ,cheese or ham ,and salad which is served cold.You will often find a pub’s menu written on a blackboard .There may even be daily specials for you to try.

You must be at least 18 years old to buy alcohol(含酒精的饮料)in England. Children under 14 years old are not usually allowed inside a pub, but families with children can sit outside in the garden, known as the beer garden ,when the weather is warm .Parents are allowed to buy soft drinks for their children.

Pubs are places where people go to enjoy themselves .People like to drink, eat ,talk with friends and have a good time.If you go to an English pub ,you will get a true taste of English life.

小题1:Traditional English beer is __________.

A.served slightly cold

B.served in pint glasses only

C.Served by waiters

D.called lager小题2:The bar staff ___________________.

A.are called waiters

B.expect you to tip them

C.pour your drinks before you pay

D.pour your drinks after you pay小题3:If you ‘buy a round’,you ______

A.pay for your drinks at the end of a meal

B.taste a variety of beers

C.share the cost of drinking with friends

D.pay for your own drinks小题4:.Pub food _______

A.is cheese or ham

B.doesn’t cost much money

C.is called a ‘bar snack’

D.is special English meal小题5:.Children _________

A.are allowed in pubs

B.can not drink alcohol

C.must not eat pub food

D.must buy rounds of drinks小题6:English pubs______

A.serve only alcoholic drinks

B.are for families only

C.serve both food and drink

D.are no longer common in England

选择题