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• FeS的电离中c(Fe+)*c(s2-)=6.25*10^-18,又知溶液中,[c(H+)]^2*c(S2-)=1*10^-22现将适量的FeS,投入饱和溶液中,要使溶液的c(Fe2+)达到1mol/L,应调节溶液的PH为多少?
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• FeS饱和溶液中c(Fe2+)c(S2与c（H+）*c(OH-)=Kw类似,FeS饱和溶液中c（Fe2+)*c(S2-)=Ksp.常温下Ksp=8.1*10-17.理论上FeS的溶解度为?而事实上其浓度远大于这个数值,其原因可能是?
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• 阅读选择：We have a nice classroom.The windows are big and the wals are white.There's a bigblackboard on the front wall.A big desk is near it.It is for our teachers.There's a map of China and some other pictures on the wall.There are forty small desks and chairs in the room.They are for students.There are sixteen girls and twenty-four boys in our class.There are some flowers on the teacher's desk.They're for our English teacher.She is  a good teacher and w
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• 如图,正方形ABCD,E、F分别是CD、DA上的点,BF平分角ABE,说明BE=AF=CE
• ABCD是正方形,E,F分别是CD,DA上的点,BF平分角ABE,求证BE=AF+CE