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问题 填空题

（1）工业用盐亚硝酸钠的化学式（其中氮元素的化合价为+3价）______；

（2）亚硫酸钠Na2SO3 中硫元素的化合价______；

（3）碳酸钠中的阴离子______；

（4）用化学方程式表示以下两题：

不能用铁制容器配制波尔多液（含硫酸铜）的原因______．

实验室用高锰酸钾制氧气的反应原理______．

答案

（1）亚硝酸钠中钠元素显+1价，亚硝酸根显-1价，其化学式为：NaNO2．

（2）由化合价的表示方法，在其化学式该元素的上方用正负号和数字表示，正负号在前，数字在后，故亚硫酸钠Na2SO3中硫元素的化合价可表示为：Na2

+4
S
O3．

（3）碳酸钠中的阴离子是碳酸根离子，其离子符号为：CO32-．

（4）铁和硫酸铜溶液发生置换反应生成硫酸亚铁和铜，故不能用铁制容器配制波尔多液，反应的化学方程式为：Fe+CuSO4═FeSO4+Cu．

高锰酸钾在加热条件下生成锰酸钾、二氧化锰和氧气，反应的化学方程式是2KMnO4

  △  
.
 
K2MnO4+MnO2+O2↑．

故答案为：（1）NaNO2；（2）Na2

+4
S
O3；（3）CO32-；（4）Fe+CuSO4═FeSO4+Cu；2KMnO4
  △  
.
 
K2MnO4+MnO2+O2↑．

单项选择题

留置胃肠减压管预防肺部感染的处理不包括（）

A.减压期间禁食

B.口腔护理

C.减少谈话和不必要的刺激

D.必须经胃管给药者，应在服药后停止抽吸半小时

E.保持引流通畅，防胃液返流
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单项选择题

The United States government publishes guidelines for appropriate nutrient intakes. These are known as the Recommended Dietary Allowances (RDAs) and are updated regularly based on new research in nutrition. RDAs are suggested amounts of calories, protein, and some minerals and vitamins for an adequate diet. For other dietary substances, specific goals must await further research. However, for the U.S. population as a whole, increasing starch and fiber in one’s diet and reducing calories (primarily from fats. sugar, and alcohol) is sensible. These suggestions are especially appropriate for people who have other factors for chronic diseases due to family history of obesity, premature heart disease, diabetes, high blood pressure, and high blood cholesterol, or for those who use tobacco.
Snacks can furnish about one-fourth of the calorie requirements among teenagers. Those snacks should also provide much of the day’s allowances for protein, minerals, and vitamins. Sandwiches, fruit, and milk make good snacks for active teenagers. Food from the food pyramid may be part of any meal. A grilled cheese sandwich or a bowl of whole-grain cereal is just as nutritious in the morning as it is at noon. In addition, a good breakfast consists of any foods that supply about one-fourth of the necessary nutrients for the day.

The reduction of calories in the diet is particularly good for people who suffer from ______.

A．obesity

B．premature heart disease and diabetes

C．high blood pressure and cholesterol levels

D．all of the above
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