Question

13.
SECTION - C
3 x 12
Determine the molecular formula of an oxide of iron in which the mass per cent of iron
and oxygen are 69.9 and 30.1 respectively. Given that molar mass of the oxide is 159.898
mol-1.​

Answer 1

69.9×159.898/100= 111.768

this is mass of iron in its oxide

divide this mass by molecular mass of iron for getting to know no of moles of Fe

you will find 2 moles of Fe

do the same with OXygen

30.1×159.898/100= 48

divide this by 16

you will get 3 moles of O

and the formula of iron oxide will become Fe2O3 ;

hope it helps!