Question

You must determine the identity of a metal, M, based on the following data. If M is part of a metal sulfate, it is composed of 40.5% M, 19.9% S and 39.6% O. If it is part of a chloride, it is composed of 48.0% M and 52.0% Cl.

Answer 1

Let, the metal sulfate will be MSO₄ and metal chloride will be MCl₂

(1) Suppose,

Mass of metal sulfate (MSO₄) = 100 g

So,

Mass of M = 40.5 g (40.5% M)

Mass of S = 19.9 g (19.9% S)

Mass of O = 39.6 g (39.6% O)

Let,

Atomic mass of M = x g/mol

Atomic mass of S = 32.0 g/mol

Atomic mass of O = 16.0 g/mol

Now,

Molar Ratio of M:S:O in MSO₄

As we know that if the metal is divalent, then M and S are in a 1:1 ratio. So,

(2) Similarly,

Molar Ratio of M:Cl in MCl₂

Note: Atomic mass of Cl = 35.5 g/mol

putting the value of x from part (1), we get

Now, simplify this ratio, we get

So, in the MCl₂, the ratio of M and Cl is 1:2 which means the atomic mass of metal is 65.1 g/mol.

The metal which has atomic mass of 65.1 g/mol is Zn (Zinc).

Hence, the identity of a metal, M, is Zn (Zinc).

Let me know if you have any queries regarding this.