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On dissolving 2.0g of metal in sulphuric acid. 4.51g of the metal sulphate was formed. The specific heat of the metal is 0.057 cal g^(-1). What is the valency of the metal and exact atomic mass? |
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Answer» Solution :Equivalent MASS of `SO_(4)^(2-)` radical `=("Ionic mass")/("Valency")=(96)/(2)=48` Mass of metal SULPHATE =4.51 g ltbr. Mass of metal =2.0g Mass of sulphate radical =(4.51-2.0)=2.51g 2.51 g of sulphate combine with 2.0g of metal. So, 48 g of sulphate will combine with `(2)/(2.51)=48=38.24g` metal Equivalent mass of metal =38.24 ACCORDING to Dulong and PETIT's law, Approximate atomic mass `=(6.4)/("specific HEAT")=(6.4)/(0.057)=112.5` `"Valency"=("Approximately atomic mass")/("Equivalent mass")` `=(112.5)/(38.24)=2.9=3` Exact atomic mass `=38.24xx3=114.72`. |
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