问题 选择题

下列说法正确的是(    )                                                        

A.热化学方程式中,化学式前面的化学计量数既可表示微粒数,又可表示物质的量。

B.热化学方程式中,如果没有注明温度和压强,则表示在标准状况下测得的数据。

C.书写热化学方程式时,不仅要写明反应热的符号和数值,还要注明各物质的聚集状态。

D.凡是化合反应都是放热反应,分解反应都是吸热反应。

答案

答案:C

题目分析:书写和应用热化学方程式时必须注意以下几点:

(1)反应热与温度和压强等测定条件有关,所以书写时指明反应时的温度和压强(25℃、101kPa时,可以不注明)

(2)各物质化学式右侧用圆括弧()表明物质的聚集状态。可以用g、l、s分别代表气态、液态、固态。

(3)热化学方程式中化学计量数只表示该物质的物质的量,不表示物质分子个数或原子个数,因此,它可以是整数,也可以是分数。

(4)热化学方程式是表示反应已完成的数量。由于△H与反应完成物质的量有关,所以方程式中化学式前面的化学计量数必须与△H相对应,当反应逆向进行时,其反应热与正反应的反应热数值相等,符号相反。

化合反应不一定都是放热反应,分解反应不一定都是吸热反应。

点评:理解热化学方程式的书写(各物质化学式右侧用圆括弧()表明物质的聚集状态)、含义(热化学方程式中化学计量数只表示该物质的物质的量)。

阅读理解

On the high-speed train Avignon to Paris, my husband and I landed in the only remaining seats on the train, in the middle of a car, directly opposite a Frenchwoman of middle years. It was an extremely uncomfortable arrangement to be looking straight into the eyes of a stranger. My husband and I pulled out books. The woman produced a large makeup case and made up her face. Except for a lunch break, she continued this activity for the entire three-hour trip. Every once in a while she surveyed the car with a bright-eyed glance, but never once did she catch my eye. My husband and I could have been a blanket wall.

I was amused, but some people would have felt uncomfortable , even repulsed(厌恶的).there is something about making up in public that calls up strong emotional reactions. Partly it’s a question of hygiene. And it’s a matter of degree. Making up --- a private act--- has a way of neglecting the presence of others. I was once seated at a party with a model-actress who immediately waved a silly brush and began dusting her face at the table, demonstrating that while she was next to me, she was not with me.

In fact, I am generally prohibited from making up in public, except when I am in the company of cosmetics moment. In a gathering more professional than social, I would do so.

Kathy Peiss, a history professor at the University of Massachusetts in Amherst says that nose-powdering in the office was an occasion for outrage in 1920’s and 30’s. Deploring the practice as a waste of company time, trade journals advises managers to discourage it among workers. Peiss theorizes that it was female’s making up in what has been an all-male field that disturb some gentlemen.

Peiss tells me that after the 30’s , pulling out a make-up case was no longer an issue. It became an accepted practice. I asked if she feels free to apply lipstick at a professional lunch herself. Sounding mildly shocked, she says she would save that for the privacy of her car afterward. Why? Because it would be “a gesture of inappropriate feminity(女性化).” One guess is that most professional women feel this way. There is evidence of the popularity of the new lipsticks that remain in place all day without retouching.

小题1:According to the author, “My husband and I could have been a blanket wall.” (Line 6, Para.1) most probably means “________”.

A.We were treated with an expressionless face.

B.We looked at the French woman expressionlessly

C.We used books as a wall to avoid the woman’s eyes

D.We were of no existence in the French woman’s eyes小题2:In the author’s opinion, she _______.

A.allows public making up on certain occasions

B.feels comfortable when making up in public

C.only makes up on social occasions

D.makes up before any professional gatherings小题3:According to Peiss, nose powdering in an office was criticized mainly for the reason that ____.

A.normal office work was disturbed

B.it discouraged women’s interest in career

C.make dominance was emphasized there

D.it distracted make workers’ focus on work小题4:Why do most professional women give up using lipsticks in public?

A.Because they are worried about being looked down upon

B.Because it emphasizes their female features in wrong situations

C.Because it implies women’s disadvantages in academic fields

D.Because they are ashamed to be seen making up in front of males/小题5:It can be inferred that in a highly open society, the differences between men and women ______.

A.have attracted little attention

B.hinder the social development

C.are attractive topics in talk shows

D.still call for great concern

单项选择题