Question

If an element X is present 70% by weight in its oxide X2O3, then atomic mass of element X is

Answer 1

Given:

Percentage of X in X2O3 = 70 %

To Find:

The atomic mass of element X.

Calculation:

- % of Oxygen = 100 - 70 = 30%

- Let the mass of X₂O₃ be 'm'

- Mass of oxygen in given X₂O₃ = 3 x 16 = 48 grams

⇒ 30% of m = 48

⇒ 30 m/100 = 48

⇒ m = 160 gram

⇒ The molar mass of X₂O₃ is 160 grams.

- Hence, the mass of 2 'X' atoms = 160 - 48 = 112

- Atomic Mass of 'X' = 112/2

⇒ Atomic Mass of 'X' = 56 gram

- Thus, the Atomic mass of Element 'X' is 56 gram.