...的镁条4g放入100g稀硫酸中,恰好完全反应,生成0.2g气体
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发布时间:2024-10-13 22:50
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热心网友
时间:2024-10-13 23:56
(1)
Mg+H2SO4==MgSO4+H2↑
24 98 120 2
X Y Z 0.2g
24/X = 98/Y = 120/Z = 2/0.2g
X = 2.4g,Y = 9.8g,Z = 12g
镁的质量分数 = 2.4/4 = 60%
(2)
m(MgO) = 4-2.4 = 1.6g
MgO+H2SO4==MgSO4+H2O
40 98 120
1.6g a b
40/1.6g = 98所以/a = 120/b
a = 3.92g,b = 4.8g
所以稀硫酸的质量分数 = (Y+a)/100 = (9.8+3.92)/100 = 13.72%
(3)
m(MgSO4) = Z+b = 16.8g
反应后溶液质量 = 4+100-0.2 = 103.8g
所以反应后溶液的质量分数 = 16.8/103.8 = 16.2%
热心网友
时间:2024-10-13 23:59
60% 98% 85.7%