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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)A. 96B. 84C. 60D. 75 |
Answer» Correct Answer - B `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%`. |
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