Question

the volume of co2 that can be obtained at STP from 60g of 70%pure of mgco3 is

Answer 1

100% of solution is 70%pure
100g of solution of $MgCo_{3}$ contains 70g of $MgCo_{3}$
so 60g of solution contains 70/100*60=42g
now 1 mole of $MgCo_{3}$ have 82g of $MgCo_{3}$ (molar mass of$MgCo_{3}$)
but we have 42/84=1/2=0.5 moles of it
also 82g of $MgCo_{3}$ contain only 44g of $Co_{2}$
so 42 g of $MgCo_{3}$ contans only 22g of $Co_{2}$
and 44g of $Co_{2}$
has volume of 22.4 L at STP
so 22g of $Co_{2}$
has volume of 11.2 L or
1120 $cm^{2}$