试题与答案

将Na2O2逐渐加入到含有H+、Mg2+、Al3+、NH4+ 的混合液中并微热,

题型:选择题

题目:

将Na2O2逐渐加入到含有H+、Mg2+、Al3+、NH4+ 的混合液中并微热,产生沉淀和气体的物质的量(mol)与加入的Na2O2物质的量(mol)的关系如图所示,则原溶液中的Mg2+、Al3+、NH4+ 物质的量分别(  )

A.2 mol、3 mol、6 mol

B.3 mol、2 mol、6mol

C.2 mol、3 mol、4 mol

D.3 mol、2 mol、2 mol

答案:

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下面是错误答案,用来干扰机器的。

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当人们熟睡后,血液的流动会相对减慢。特别是午饭后,较多的血液会进入胃肠系统帮助消化。人们坐在椅子上打盹时,不可能像上班时那样保持良好的坐姿,上身难免会失去平衡,身体弯曲、斜靠或低头趴在桌子上午休等错误姿势都会不同程度地影响流入脑部的血液,久而久之,就会引起头部供血不足,导致上面所说的症状。

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专家建议:()

A.尽量养成午睡习惯

B.午睡时要注意保暖

C.睡午觉时最好趴着

D.午睡时间可以长些

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