在甲乙丙丁四个烧杯中各放200ml水,然后分别放入含有2.3g钠元素的NA,NA2O,NA2O2,NAOH,将固体完全溶
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甲乙丙丁中溶质的质量分数大小关系甲>乙=丙>丁

200mlH2O的质量=200ml*1g/ml=200g

Na2O----2Na

62 46

X 2.3g

X=3.1g

Na2O2----2Na

78 46

Y 2.3g

Y=3.9g

NaOH-----Na

40 23

Z 2.3g

Z=4g

2Na+2H2O=2NaOH+H2↑

46 80 2

2.3g X1 X2

X1=4g

X2=0.1g

甲中溶质的质量分数=4g/(2.3g+200g-0.1g)*100%=1.98%

Na2O+H2O=2NaOH

46 80

3.1g Y1

Y1=4g

乙中溶质的质量分数=4g/(3.1g+200g)*100%=1.97%

2Na2O2+2H2O=4NaOH+O2↑

156 160 32

3.9g Z1 Z2

Z1=4g

Z2=0.8g

丙中溶质的质量分数=4g/(3.9g+200g-0.8g)*100%=1.97%

丁中溶质的质量分数=4g/(4g+200g)*100%=1.96%

则甲乙丙丁中溶质的质量分数大小关系甲>乙=丙>丁