用50mL0.50mol/L盐酸与50mL0.55mol/LNaOH溶液在如图所

题型:实验题

问题:

用50mL0.50mol/L盐酸与50mL0.55mol/LNaOH溶液在如图所示的装置中进行中和反应。通过测定反应过程中所放出的热量可计算中和热。回答下列问题

(1)从实验装置上看,图中尚缺少的一种玻璃用品是____________。

(2)烧杯间填满碎纸条的作用是____________。

(3)大烧杯上如不盖硬纸板,求得的中和热数值________(填“偏大、偏小、无影响”)

(4)如果用60mL0.50mol/L盐酸与50mL0.55mol/LNaOH溶液进行反应,与上述实验相比,所放出的热量

________ (填“相等、不相等”),所求中和热_________(填“相等、不相等”),简述理由________________________。

(5)用相同浓度和体积的氨水(NH3·H2O)代替NaOH溶液进行上述实验,测得的中和热的数值会___________(填“偏大”、“偏小”、“无影响”)。

考点:中和热的测定
题型:实验题

已知集合U=R,A={x|x2-5x+6≥0},那么∁UA=(  )

A.{x|x<2或x>3}

B.{x|2<x<3}

C.{x|x≤2或x≥3}

D.{x|2≤x≤3}

题型:实验题

下列关于热型的叙述,错误的是

A.斑疹伤寒常为稽留热

B.弛张热是指体温在38℃以上,一天内波动不超过2℃

C.肺结核常为不规则热

D.间歇热是发热期和无热期交替出现

E.发热不一定是感染引起的

题型:实验题

Teaching a child to read at a young age gives him a valuable start in life. Reading is the basic part of education and a child’s reading ability will influence his school success greatly. Learning difficulties, many of which begin from poor reading skills, can damage a school child’s confidence and affect his future achievement. Young children are programmed to learn and they can learn better with encouragement. Ten to twenty minutes of reading a day still leaves plenty of time for play.

Many parents are concerned that learning to read is too challenging a task for a pre-school child, but they should also remember that most children learn to speak by the time they are 3. Learning a language is probably the single most challenging task any individual can undertake, yet children do it without formal instruction, achieving the fluency much better than adult language students.

There is a window of opportunity in terms of IQ development, which is most open during a child’s early years. A scientific study, carried out by Dr. Peter Huttenlocher at the University of Chicago, showed that the number of connectors, called synapses(神经元突触), between the nerve endings in a newborn baby’s brain is similar to the number in the average adult brain. These synapses increase rapidly during early childhood. By 12-24 months a child’s brain has about 50% more synapses than the average adult brain. After that the synapses which are not in use begin to atrophy(衰退). For most people, from age 16, the number remains steady. It begins to drop again as we move into our golden years. Doing intellectual activities at a young age, such as learning to read, can stimulate(刺激)and preserve these connectors in the brain resulting in a long-term beneficial(有益的)effect on IQ development.

Another notable study is probably the Milwaukee project. This study took a group of babies, all of whose mothers had low IQs, and gave them special training for seven hours a day, five days a week, until they started first grade. By the age of 6 these children had an average IQ 30 points higher than their contemporaries. The overwhelming conclusion is that the early intellectual stimulation can have a positive, long-term effect on a child’s brain development.

From birth you should talk to and explain things to your baby. Reading to him can be a wonderful way of spending quality time with your child. The enjoyment of books and being familiar with the idea of print will pave the way for(为……铺平道路)learning to read later.

If your child is a fast learner you can help him realize his potential by introducing him to the joy of the printed word at an early age. This will lay the foundations(基础)for both a high achieving school career and a lifelong love of reading. If your child shows early signs of reading difficulties, your efforts may help him get rid of such problems before he goes to school.

It can be difficult to teach your own child because emotional(引起情绪激动的)issues arise easily. Online programs for learning to read English are excellent options. They allow children to repeat new materials as many times as they need to, without wearing out the parents’ patience.

小题1:What does the passage mainly discuss?

A.Children should be taught to read at an early age.

B.Children can read better than most adult students.

C.Children have more synapses than most adults.

D.Children are supposed to learn to read on the Internet.小题2:Why does the author mention the study by Dr. Peter Hutten locher?

A.To remove parents’ worry.

B.To explain IQ development.

C.To explain how a baby’s brain works.

D.To show the parents’ wrong ideas.小题3:How can children benefit from learning to read at a young age?

A.It can build up great confidence in their mind.

B.It can help preserve the connectors in their brains.

C.It can help produce more connectors in their brains.

D.It can help them find both their weaknesses and strengths.小题4:At the end of this passage the author advises _______.

A.parents not to get angry too often

B.children to enjoy reading as early as possible

C.children not to wear out their parents’ patience

D.parents to get their children to take an online program

题型:实验题

诊断皮肤癌性溃疡首选的病理检查方式是()。

A.穿刺活检

B.切取活检

C.切除活检

D.脱落细胞检查

E.刷落细胞检查

题型:实验题

闭路电视监控系统的功能可分为摄像、传输、控制和显示记录四个部分,其中( )的任务是把现场摄像机发出的信号传送到控制中心,它一般包括线缆、调制解调设备、线路驱动设备等。

A.摄像部分
B.传输部分
C.控制部分
D.显示记录

更多题库