20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample ? (At. Wt of Mg = 24)

20.0 g of a magnesium carbonate sample decomposes on heating to give c

1.	20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample ? (At. Wt of Mg = 24)
Answer» 96 84 60 75 Solution :`UNDERSET(84g)(MgCO_(3))overset(HEAT)(rarr)underset(40g)(MgO)+CO_(2)` 84 g of `MgCO_(3)` yield upon heating MgO = 40 g 20 g of `MgCO_(3)` yield upon heating `MgO=((40g)xx(20g))/((84g))` `=9.52g` Weight of MgO ACTUALLY formed = 8.0g % purity of `MgCO_(3)=((8.0g))/((9.52g))xx100=84%`.