2013年4月24日，东航首次成功进行了由地沟油生产的生物航空燃油_爱下问搜题

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问题选择题

2013年4月24日，东航首次成功进行了由地沟油生产的生物航空燃油的验证飞行。能区别地沟油（加工过的餐饮废弃油）与矿物油（汽油、煤油、柴油等）的方法是

A．点燃，能燃烧的是矿物油

B．测定沸点，有固定沸点的是矿物油

C．加入水中，浮在水面上的是地沟油

D．加入足量氢氧化钠溶液共热，不分层的是地沟油

答案

答案：D

题目分析：进行物质的检验时，要依据物质的特殊性质和特征反应，选择适当的试剂和方法，准确观察反应中的明显现象，如颜色的变化、沉淀的生成和溶解、气体的产生和气味、火焰的颜色等，进行判断、推理、验证即可。A、地沟油与矿物油都能燃烧，不能鉴别，A不正确；B、地沟油与矿物油都是混合物，没有固体的熔沸点，不能鉴别，B不正确；C、地沟油与矿物油的密度都小于水，不溶于水，不能用水鉴别，C不正确；D、地沟油主要成分是油脂，属于酯类，能与氢氧化钠溶液加热发生水解反应。而矿物油主要成分是烃类，与氢氧化钠溶液不反应，可以鉴别，D正确，答案选D。

选择题

下列离子中，所带电荷数与该离子的核外电子层数相等的是（）

A．Al³⁺

B．Mg²⁺

C．Be²⁺

D．H⁺

问答题

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The magazine cover showing an attractive mother holding a cute baby is hardly the only Madonna-and-child image on newsstands this week. There are also stories about newly adoptive—and newly single-morn Sandra Bullock, as well as the usual "Jennifer Aniston is pregnant" news. Practically every week features at least one celebrity morn, or mom-to-be, smiling on the newsstands.
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Of course, the image of parenthood that celebrity magazines like Us Weekly and People present is hugely unrealistic, especially when the parents are single mothers like Bullock. According to several studies concluding that parents are less happy than childless couples, single parents are the least happy of all. No shock there, considering how much work it is to raise a kid without a partner to lean on; yet to hear Sandra and Britney tell it, raising a kid on their "own" (read: with round-the-clock help) is a piece of cake.
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