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问题 单项选择题

患者，黄某，36岁，行甲状腺大部分切除术术后3天，出现手足疼痛，指尖针刺感并有轻度抽搐，护士应备好（）。

A.氯化钾

B.碘化钾

C.苯巴比妥

D.碳酸氢钠

E.葡萄糖酸钙

答案

参考答案：E

填空题

味精是烹制菜肴时常用的调味品，其主要成分是谷氨酸钠．谷氨酸钠有鲜味，易溶于水．小明发现某品牌味精包装上标注：“谷氨酸钠含量≥80%，NaCl含量≤20%”，他想测定此味精中NaCl的含量．

查资料：NaCl+AgNO3=AgCl↓+NaNO3，谷氨酸钠的存在不影响NaCl性质．

实验过程：

①称取该味精样品5.0g，并溶于蒸馏水；②加入过量的硝酸银溶液；③过滤；④用蒸馏水反复洗涤沉淀物多次；⑤将沉淀物烘干、称量，测得固体质量为2.87g．

根据上述实验步骤回答下列有关问题：

（1）过滤操作所需要的仪器除烧杯、铁架台（带铁圈）、玻璃棒外，还需要的玻璃仪器是______；

（2）此样品中NaCl的质量分数为______，是否符合其包装上标注的标准？______．

应用：最近专家否认了“味精致癌”的说法．实验表明，味精在100℃加热半小时，只有0.3%的味精（谷氨酸钠）生成焦谷氨酸钠（有毒），其对人体的影响甚微．对此下列认识正确的是______．

A．谷氨酸钠受热不发生化学变化

B．谷氨酸钠在加热下生成焦谷氨酸钠是物理变化

C．大量食用味精不利于身体健康

D．研究问题的一种有效方法是通过实验．
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单项选择题

Recent epidemiological studies have shown that the residents of Greenborough County have substantially higher rates of pancreatic and stomach cancer than do the residents of the state as a whole. Researchers have concluded that the high rates of these cancers are due to the presence in the county of a large petrochemical facility that manufactures chemicals known to be carcinogenic.
Which of the following, if true, most weakens the researchers’ conclusion ？（）

A. The county’s residents have the highest rate in the state of smoking, a habit that has been conclusively linked with higher rates of several types of cancer.

B. The residents of the county get their water from springs that could not have been contaminated by the petrochemical plant implicated by the researchers.

C. The petrochemical plant has been found to be in violation of EPA emissions standards five times in the last two years.

D. Residents of Greenborough County, like people throughout the state, are fond of spicy and fatty foods that have been linked to a number of health problems.

E. There are no known medical treatments that can permanently halt the development of certain forms of pancreatic cancer.
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