Question

10 gram of a metal oxide X2O3 contains 4 gram metal then find atomic weight of the metal?​

Answer 1

According to Question

$10g \: X_{2}O_{3} = = = > 4g \: metal \\ 100 \: X_{2}O_{3} = = = > 40g \: metal$

So

$Percent \: by \: mass = 40$

$\boxed{Mass \% = \frac{Mass \: of \: the \: Element}{Mole \: Atom} \times 100}$

On putting all values

$=> 40 = \frac{2x \times 100} {2x + 48} \\ = > 80x + 1920 = 200x \\ = > 1920 = 200x - 80x \\ = > 1920 = 120x \\ = > x = \frac{ \cancel1920}{ \cancel120} \\ = > \boxed{x = 16g}$

Therefore

Therefore Weight of the metal will be 16g.