On dissolving 2.0 g of a metal in sulphuric acid, 4.51 grams of the metal sulphate was formed. The specific heat of the metal is 0.057 cal/g. What is the valency of the metal and its exact atomic weight?

On dissolving 2.0 g of a metal in sulphuric acid, 4.51 grams of the me

1.	On dissolving 2.0 g of a metal in sulphuric acid, 4.51 grams of the metal sulphate was formed. The specific heat of the metal is 0.057 cal/g. What is the valency of the metal and its exact atomic weight?
Answer» SOLUTION :LET the formula of the metal sulphate be `M_(2)(SO_(4))_(x)` ( x being the valency of the metal M) `:. X xx` moles of M = `2xx ` moles of `SO_(4)^(-2)` or `x xx "(wt.of M")/("ATOMIC weight of M ") = 2 xx ("wt. of sulphate ion ")/(" ionic wt. of "SO_(4)^(2-))` `x xx (2)/(112) = 2 xx((4.51-2))/(96)` `x= 2.85 =3` { at wt. of M = `(6.4)/(0.057) =112 ` (APPROX).} The valency is, therefore, 3. Now, SUBSTITUTE the valency of x as 3 in eqn. (1) again to calculate the accurate value of the atomic weight of the metal.