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问题 计算题

环保部门测定某气体样品中一氧化碳的含量，其方法和实验步骤如下：

(1)将2.000 L的气体样品通过盛有I2O5固体的加热管，发生的反应为：5CO+I2O55CO2+I2。

(2)将所产生的碘升华，并加入30.00 mL 0.005 0 mol·L-1的硫代硫酸钠溶液，发生的反应为：I2+2====2I-+。

(3)将(2)中溶液取出，加入1.00 mL 0.010 0 mol·L-1的碘水，正好将所取溶液中过量的Na2S2O3全部氧化。

试计算1 L该气体样品中有多少毫克(mg)的CO。

答案

1.75 mg

根据题意，反应中各物质间的关系为：5CO—I2—2

得与CO和I2O5反应生成的I2的物质的量为：

n()="0.005" 0 mol·L-1×30.00 mL×10-3L·mL-1-5×0.010 0 mol·L-1×1.00 mL×10-3 L·mL-1×2=5.00×10-5 mol

n(CO)=n()=×5.00×10-5 mol=1.25×10-4 mol

m (CO)=1.25×10-4 mol×28 g·mol-1=3.50×10-3 g

c (CO)==1.75×10-3 g·L-1="1.75" mg·L-1。

阅读理解

D

I know what you’re thinking: pizza（比萨饼）? For breakfast? But the truth is that you can have last night’s leftovers in the a.m. if you want to.

I know lots of women who skip breakfast（不吃早餐）, and they have a ton of different excuses for doing it. Some say they don’t have time; others think they’re “saving” calories（卡路里）；still others just don’t like breakfast food . 

But the bottom line is that eating in the morning is very important when you’re trying to lose weight. “Eating just about anything from 300 to 400 calories would be better than nothing at all,” says Katherine Brooking R.D., who developed the super-easy eating plan for this year’s “SELF CHALLENGE”. And even pizza can be healthy if it’s loaded with vegetables, and you stick to one small piece. 

Breakfast is one meal I never miss, and the same goes for most weight loss success stories. Research shows that eating breakfast keeps you from overeating later in the day. Researchers at the University of Southern California found that breakfast skippers have a bigger chance of gaining weight than those who regularly have a morning meal.

So eat something in the morning, anything. I know plenty of friends who end up having no breakfast altogether, and have just coffee or orange juice. I say, try heating up last night’s leftovers—it may sound crazy, but if it works for you, do it! I find if I tell myself, “You can always eat it tomorrow,” I put away the leftovers instead of eating more that night. Try it. You may save yourself some pre-bedtime calories. And watch your body gain the fat-burning effects.

68. The word “leftovers” in Paragraph 1 probably means_______. 

A. food remaining after a meal         B. things left undone

C. meals made of vegetables           D. pizza topped with fruit

69. What can we infer from the text?

A. Working women usually have breakfast in a hurry.

B. Many people have wrong ideas about breakfast. 

C. There are some easy ways of cooking a meal. 

D. Eating vegetables helps save energy. 

70. According to the last paragraph, it is important to________. 

A. eat something for breakfast           B. be careful about what you eat

C. heat up food before eating it          D. eat calorie-controlled food

71. The text is written mainly for those________. 

A. who go to work early        B. who want to lose weight

C. who stay up late            D. who eat before sleep

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单项选择题 A3/A4型题

患者女性，43岁，近日出现尿频、 * * 烧灼痛，就医检查，确诊淋球菌引起的泌 * * 感染。服用磺胺异噁唑治疗，用药后出现严重的溶血性贫血。

出现的严重反应属于（）

A.药物副作用

B.药物变态反应

C.药物毒性反应

D.药物继发反应

E.药物特异质反应
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