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题目列表(包括答案和解析)

19、某工厂在装配一件设备时,不小心把一个用镁合金制造的精密空心小球掉到一个又深、又小的坚固的水泥小洞中,用各种工具都取不出来,有人提出往小洞中倒入某种溶液使小球浮起的方法.现有三种物质的溶解度数据(注:水的密度为1g/cm3,溶液的体积变化忽略不计.)
在保证不损坏小球的前提下,理论上可以用上表中
硝酸钾
物质配制成溶液,倒入小洞中使小球浮起,该溶液的最低温度应保持在
40
℃以上(已知该小球的密度为1.60g/cm3).在以上计算所得的最低温度时,该饱和溶液溶质的质量分数是
39%
;若小洞的容积为4000mL,要配制4000mL上述饱和溶液,理论上至少需要溶质
2558.4
g.

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完型填空(共20小题;每小题1分,满分20分)
阅读下面短文,掌握其大意,然后从四个选项(A、B、C和D)中,选出最佳选项。
"Hey, Tahlia! How's the model?"
I had just taken a bite of my hot dog __21__ I heard a familiar voice yelling at me from across the crowded school yard. I saw a group of popular girls who were all __22__.
"What kind of __23_ are you going to do? An ad for a Frankenstein movie?" More laughter. My stomach twisted into a tight knot. How could they humiliate (羞辱) me like this, __24__ the entire school? As I walked into the cafeteria, I __25__ the dark scars on my right hand.
At 9 months old, I knocked over a tea pot and dumped boiling water allover my hands and stomach. My parents __26__ me to the hospital, but I had to have skin graft (移植) operation. I was in so much pain! But what __27__ me most were the cruel things people said about how I looked, __28__ that day at lunch.
The girls were being supermean to me because they'd heard I was considering doing some modeling. A close friend had suggested that I shouldn't let my scars limit me and that I might __29__ a good model.
But after that __30__ at school, I was sure I'd made a huge mistake. Upon arriving home, I covered the mirror with a blanket, fell on my bed and sobbed.
The next day, I __31__ myself to go to school. At lunch my best friend Jesse tried to encourage me: "You can't __32_ forever, Tahlia. So what if you have a few scars? Just go outside and show them that you're just as good as they are." Although I knew he was right, I couldn’t __33__ standing up for myself like that.
However, that night as I sat on the bed, my friend's words replayed in my mind. I'm __34__ hiding from myself, I thought. How stupid! Slowly, I stood up, walked over to the __35__, and tossed the blanket aside. There, in the mirror I saw a slim, dark-haired, blue-eyed girl, looking just fine, __36__ with a few scars.
The next day I wore a comfortable T-shirt to school. What's more, I had lunch outside the cafeteria, __37__ beside those mean girls. They were shocked that I should dare to walk into their territory. I felt __38_ too—free and happy.
Sometimes people still look at me strangely. They __39_ and stare, but I don't let it get to me. I have applied to several modeling companies, and at least one company is considering me for jobs. Maybe I'll never __40_ posing on the runway, but I do know one thing: I'm done.
【小题1】
A.as B.when C.while D.before
【小题2】
A.applauding B.cheering C.laughing D.quarreling
【小题3】
A.modeling B.writing C.drilling D.acting
【小题4】
A.in spite of B.in view of C.in terms of D.in front of
【小题5】
A.looked into B.searched for C.wondered aboutD.glanced at
【小题6】
A.presented B.sent C.rushedD.handed
【小题7】
A.hurtB.beat C.disappointed D.puzzled
【小题8】
A.for B.like C.on D.after
【小题9】
A.impressB.make C.consult D.defeat
【小题10】
A.effect B.phenomenon C.challenge D.scene
【小题11】
A.forced B.expected C.reminded D.preferred
【小题12】
A.apologize B.beg C.hide D.complain
【小题13】
A.consider B.imagine C.appreciate D.resist
【小题14】
A.hardly B.ever C.even D.gradually
【小题15】
A.blanket B.bed C.chair D.mirror
【小题16】
A.while B.though C.but D.because
【小题17】
A.right B.still C.therefore D.anyhow
【小题18】
A.sensitive B.uncomfortable C.different D.tense
【小题19】
A.compare B.associate C.wave D.whisper
【小题20】
A.give up B.end up C.put up D.set up

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实验探究氢气遇到氧气发生爆炸的条件:
①甲装置中仪器“A”的名称是
 
;在实验室中利用氯酸钾和二氧化锰制取氧气,发生的化学方程式是
 
;利用锌粒和稀硫酸制取氢气,可以利用下列
 
(选填“甲”或“乙”)装置;
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②利用丙装置将氢气、氧气混合气体收集起来,可以观察
 
数量,通过活塞控制两者气体的比例关系,利用一次性保鲜袋收集混合气体,然后直接点燃保鲜袋.
③实验共四次,实验数据及现象记录在下表:
实验次数 第一次 第二次 第三次 第四次
氢气与氧气的体积比 1:2 1:4 1:19 1:39
氢气的体积百分数 33% 20% 5% 3.3%
点燃后现象 爆炸 爆炸 爆炸 保鲜袋燃烧,没有爆炸
由此可见氢气与氧气混合发生爆炸,除要达到燃烧的三个条件外,还和
 
有关.

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实验探究氢气遇到氧气发生爆炸的条件:

①甲装置中仪器“A”的名称是(17)     ;在实验室中利用氯酸钾和二氧化锰制取氧气,发生的化学方程式是(18)               ;利用锌粒和稀硫酸制取氢气,可以利用下列

(19)   (选填“甲”或“乙”)装置;

②利用丙装置将氢气、氧气混合气体收集起来,可以观察(20)                 数量,通过活塞控制两者气体的比例关系,利用一次性保鲜袋收集混合气体,然后直接点燃保鲜袋。

③实验共四次,实验数据及现象记录在下表:

实验次数

第一次

第二次

第三次

第四次

氢气与氧气的体积比

1︰2

1︰4

1︰19

1︰39

氢气的体积百分数

33%

20%

5%

3.3%

点燃后现象

爆炸

爆炸

爆炸

保鲜袋燃烧,没有爆炸

由此可见氢气与氧气混合发生爆炸,除要达到燃烧的三个条件外,还和(21)       有关。

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实验探究氢气遇到氧气发生爆炸的条件:

(1)甲装置中仪器“A”的名称是         ;在实验室中利用氯酸钾和二氧化锰制取氧气,发生的化学方程式是                    ;利用锌粒和稀硫酸制取氢气,可以利用下列       (选填“甲”或“乙”)装置;

(2)利用丙装置将氢气、氧气混合气体收集起来,可以观察                 数量,通过活塞控制两者气体的比例关系,利用一次性保鲜袋收集混合气体,然后直接点燃保鲜袋。

(3)实验共四次,实验数据及现象记录在下表:

实验次数

第一次

第二次

第三次

第四次

氢气与氧气的体积比

1︰2

1︰4

1︰19

1︰39

氢气的体积百分数

33%

20%

5%

3.3%

点燃后现象

爆炸

爆炸

爆炸

保鲜袋燃烧,没有爆炸

 

由此可见氢气与氧气混合发生爆炸,除要达到燃烧的三个条件外,还和           有关。

 

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