问题 问答题

某同学采用如图所示装置进行Fe粉与水蒸气的反应.

(1)写出Fe粉与水蒸气反应的化学方程式______.

(2)该同学向反应后的固体中加入过量的稀HCl,并将溶液分装在两支试管中.

①向第一支试管中滴加KSCN溶液,溶液呈红色,该溶液中存在的阳离子有______.

②向第二支试管中加入适量铁粉.该过程中发生化合反应的离子方程式是______.

再向所得溶液中滴加NaOH溶液并放置一段时间,该步反应中的实验现象是______.发生的氧化还原反应的化学方程式是______.

答案

(1)该反应的化学方程式是:3Fe+4H2O(g)

高温
.
Fe3O4+4H2

故答案是:3Fe+4H2O(g)

高温
.
Fe3O4+4H2

(2)①滴加KSCN溶液,溶液呈红色,证明有Fe3+,反应后的固体中一定含有剩余的铁,和盐酸反应生成氯化亚铁,溶液中含有氢离子;

故答案是:Fe3+、Fe2+、H+

②加入适量铁粉,铁和Fe3+反应,反应的离子方程式是:2Fe3++Fe═3 Fe2+;加入氢氧化钠溶液后,现象是:产生白色沉淀,迅变成灰绿色,最终速变成红褐色;反应的化学方程式为:4Fe(OH)2+O2+2 H2O═4 Fe(OH)3

故答案是:2Fe3++Fe═3 Fe2+; 产生白色沉淀,迅变成灰绿色,最终速变成红褐; 4Fe(OH)2+O2+2 H2O═4 Fe(OH)3

选择题
阅读理解

You’re standing in the dairy section at the grocery store, searching for your favorite brand. Suddenly, you catch a smell of chocolate cookies. You forget about dairy and head for the bakery (烘烤食品) section. Guess what? You just walked into an odor (气味) trap (陷阱)! The odor was cooked up by scientists in a lab.

For years, scientists have been studying the special powers of smell. They found that more than our other senses, smell changes our mood and helps us remember things.

So companies have begun spending thousands of dollars to scent (使充满香味) entire stores. Artificial (人造的) scents are being used to lead customers by the nose. These smells help to get people inside and put them in the mood to buy. They even make customers remember the store later, so they’ll come back for more. Also, many companies have smartly made use of product smells. A company added lemon fragrance to its dish cleaner. They wanted people to think the soap contained “natural” cleaners. It worked!

New uses for smells are being created every day. One bank, for example, gives customers coupons (优惠券) advertising car loans (贷款). To get people to take out a loan, bank officials hope to coat these coupons with the fresh leather smell of a new car. In Australia, telephone offices are putting sweat odor on unpaid bills. Since some people sweat when they’re scared, this smell might remind them of when they were frightened. And they’ll pay the bills right away!

What lies ahead for our noses? Smell scientists are working on some pretty far-out ideas. Would you believe TV sets that produce smells? Or how about scent diets? Certain food smells will fool your stomach into thinking it’s full. Alarm clocks will scent your bedroom with a strong pleasant smell designed to wake you up. Scientists are even working on ways to keep garbage from smelling. Researchers expect scents to help students make more sense of what they’re learning.

And just think. Someday soon, even your homework may smell nice!

小题1:How do sales methods affect customers in the stores?

A.They change customers’ preferences.

B.They persuade customers to use credit cards.

C.They make customers avoid bad and unsafe products.

D.They influence customers to make unplanned purchases.小题2:Why do telephone offices put sweat odor on unpaid bills?

A.Because the sweat odor is a reminder of terrifying experience.

B.Because the sweat odor can change people’s attitude.

C.Because most people don’t think much of sweating.

D.Because many people dislike paying bills.小题3:What does the author mean by saying “Someday soon, even your homework may smell nice!”?

A.Students would benefit more from smell research.

B.Students would be more willing to do homework.

C.Smell research would develop beyond our imagination.

D.Smell research would make great differences to our life.小题4: Why does the author write this passage?

A.To encourage the store owners to use smells.

B.To expose wrong practices by smell scientists.

C.To inform the readers of an interesting subject.

D.To blame the advertisers that use smells to sell.