将10.1克过氧化钠和钠的混合物跟120.1克水充分反应后，收集到的_爱下问搜题

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问题填空题

将10.1克过氧化钠和钠的混合物跟120.1克水充分反应后，收集到的气体体积在标准状况下为2.24L。

（1）试分别写出过氧化钠跟水反应的离子、化学方程式；（2）计算原混合物中过氧化钠和氧化钠的物质的量之比，n(Na₂O₂)：n(Na)＝。

（3）计算所得溶液的质量分数是多大？ω＝。

答案

（1） 2Na₂O₂+2H₂O＝O₂↑+4 NaOH、 2Na₂O₂+2H₂O＝O₂↑+4OH^-+4Na⁺

（2）1:1

（3）9.34℅

题目分析：（1）过氧化钠溶于水生成氢氧化钠和氧气，反应的化学方程式和离子方程式分别是2Na₂O₂+2H₂O＝O₂↑+4 NaOH、2Na₂O₂+2H₂O＝O₂↑+4OH^-+4Na⁺。

（2）设过氧化钠和钠的物质的量分别是x和y，则78g/mol×x＋23g/mol×y＝10.1g。由方程式可知

2Na₂O₂+2H₂O＝O₂↑+4 NaOH

2 2 1 4

x x 0.5x 2x

2Na+2H₂O＝H₂↑+2NaOH

2 2 1 2

y y 0.5y y

所以0.5x＋0.5y＝＝0.1mol

由78g/mol×x＋23g/mol×y＝10.1g可知x＝y＝0.1mol

原混合物中过氧化钠和氧化钠的物质的量之比，n(Na₂O₂)：n(Na)＝1:1。

（3）根据（2）中可知生成的氢氧化钠是2x＋y＝0.3mol

氢氧化钠的质量＝0.3mol×40g/mol＝12g

溶液的质量＝10.1g＋120.1g－0.05mol×32g/mol－0.05mol×2g/mol＝128.5g

所以反应后溶液的质量分数ω＝×100%＝9.34℅。

完形填空

An old man went to live with his son, daughter-in-law, and 4-year-old grandson. The old man’s hands    , his eyesight was not clear, and his    unsteady（不稳定的）. The family were    every night at the dinner table. But the elderly grandfather’s shaky hands and     sight made this rather difficult. Peas rolled off his spoon onto the floor. When he grasped the glass,       would often spill（洒落）onto the tablecloth. “We must do something about grandfather,” said the husband.
So the husband and wife set a small table in the corner. There, grandfather ate    in the corner while the rest of the family enjoyed dinner at the dinner table.       grandfather had already broken a dish or two, his food was served in a    bowl. Sometimes, when the family      grandfather, he had a tear in his eye as he ate alone.      , the only words the couple had for him were sharp    when he dropped a fork or spilled food. The 4-year-old boy watched all this      .
One evening before supper, the father      his son playing with wood scraps（小块）on the floor. He asked the child sweetly: “What are you making?” Just as      , the boy answered: “Oh, I am making a little    for you and mama to eat your food from when I grow up.” The 4-year-old boy smiled and went back to      on it.
The words    the parents so much that they were    . Then tears started to stream down their cheeks.        no word was spoken, both knew what they had to do. That evening, the husband took grandfather’s hand and      led him back to the family table.

C．disappearing

C．looked through

D．looked after

D．fortunately

多项选择题

影响预防接种免疫效果的因素有哪些？（）

A.免疫制品方面；

B.受种者机体方面；

C.保存和运输条件方面；

D.接种工作方面。