Question

in 10 gram sample of magnesium oxide the percentage composition of magnesium in 60% find the percentage number of MG atoms in the sample​

Answer 1

The molecular formula of magnesium oxide  is MgO

it's molecular mass = 24 + 16 = 40 g

=> 40 grams of MgO contains 6.023 x 10²³ atoms of Mg

=> 10 grams of MgO contains = (6.023/4) x 10²³ atoms of Mg

= 1.5 x x 10²³ atoms of Mg

Since the molecular formula is MgO

=> number of magnesium atom and number of oxygen atoms will have a ratio of 1 : 1

So number of magnesium atom and number of oxygen atoms will be equal in any amount of sample of MgO

Hence the percentage number of Mg atoms in the sample will be 50%