诱导期测定中,压力达到一定值后,会在一段时间内保持恒定不变,直到氧与汽油中的()烃类

题型:单项选择题

问题:

诱导期测定中,压力达到一定值后,会在一段时间内保持恒定不变,直到氧与汽油中的()烃类化合而脱离气相,使压力开始连续地下降。

A.饱和

B.不饱和

C.烯烃

D.炔烃

考点:油品分析工考试中级油品分析工考试中级油品分析工考试题库
题型:单项选择题

某种工业废水中含有一定量的Cr2O72-和CrO42-,它们易被人体吸收积累而导致肝癌.污水处理厂常用还原沉淀法处理含铬废水,其流程如下:

Cr42-

H+
①转化
CrO72-
Fe2+
②还原
Cr3+
OH-
③沉淀
Cr(OH)3

2CrO42-(黄色)+2H+═Cr2O72-(橙色)+H2O

①Cr2O72-中Cr的化合价是______.

②若平衡体系的pH=10,则溶液显______色.

(2)第②步发生反应的离子方程式为______,还原1molCr2O72-离子,需要______mol的FeSO4•7H2O;

(3)常温下,Cr(OH)3的溶度积Ksp=10-32,要使c(Cr3+)降至10-5mol/L,溶液的pH应调至______.

题型:单项选择题

全部位于北半球的大洲和大洋是[ ]

A、欧洲      北冰洋

B、亚洲      北冰洋

C、北美洲      印度洋

D、北美洲      大西洋

题型:单项选择题

阅读理解。

     Most people will answer a ringing phone. Usually you don't know who is phoning or how urgent

their business is, so a ringing phone is difficult to ignore. In one experiment, a researcher wrote down

the numbers of several public phones in stations and airports. Then he called the numbers. Someone

nearly always answered. When he asked why, people usually said, "Because it rang."

     A few years ago in New Jersey, a man with a rifle killed 13 people. Armed police surrounded his

house but he refused to come out. A reporter found out the phone number of the house and called.

The man put down his rifle and answered the phone. "What do you want?" he said, "I'm really busy

right now."

     Imagine you're at work and the phone is ringing in someone else's office. Do you answer it or not?

In one survey on telephone use, 51% of participants told researches that they did. We can't ignore the

phone and for the reason, it forces its way into our lives. It interrupts what we are doing and on top of

that, the caller is often someone we don't really want to talk to. However, in the survey, 58% said they

never took the phone off the hook, and 67% didn't mind if someone called during a television programme. For 44% it wasn't a problem if someone rang during a meal, while only 28% were annoyed or upset.

If someone phoned in the middle of the night, 40% told researchers that they got nervous or frightened,

while around 30% got angry.

      Of course, when someone is really annoying, you can choose to hang up on him/her. This is in fact

one of the rudest things you can do on the phone, but 79% said they were prepared to do it in some

cases. Only 6% told researchers they never hung up on people.

1. In the experiment, people answered the researcher's phone _______.

A. for fear that it was urgent

B. in order to help him gather the data

C. to test the function of the phone    

D. to show their interest in the survey

2. The gunman answered the phone because _____.

A. he decided not to give up his resistance to the police

B. he tended to answer a ringing phone

C. he wanted to tell the reporter that he was too busy to offer any information

D. he intended to be friendly with the media

3. According to Para.3, most people _____ when they were doing their work or watching television.

A. minded the ringing of the phone

B. couldn't ignore the phone

C. refused to answer the phone in someone else's office

D. kept the phone ringing

4. What is implied by the sentence "79% said they were prepared to do it in some cases"(in the

last paragraph)?

A. They were annoyed by the rude callers.

B. They were prepared to punish those rude callers.

C. They were going to hang up on annoying phones.

D. They also agreed that it was a rude thing to hang up on others.

5. The purpose of the survey is to find out _____.

A. how the phone interrupts people's work

B. what role the phone plays in people's lives

C. why people mind a ringing phone sometimes

D. when the phone communication is more welcome

题型:单项选择题

下列各组腧穴中,两穴相距1寸的是()

A.神阙、石门

B.中极、阴交

C.气海、关元

D.中脘、建里

E.中脘、下脘

题型:单项选择题

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