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) [2015]

Question

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) [2015]

Smart Achievers · Accepted Answer

(3)

$\underset{84 g}{{MgCO}_{3 (s)}} \overset{Δ}{\to} \underset{40 g}{{MgO}_{(s)}} + {CO}_{2 (g)}$

84 g of $M g C O_{3} \equiv$ 40 g of MgO

$∴$ ${20 g of MgCO}_{3} \equiv \frac{40}{84} \times 20 = 9.52 g of MgO$

Actual yield = 8 g of MgO

$∴$ $% purity = \frac{8}{9.52} \times 100 = 84 %$

Solution

Q.
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) [2015]

1 96

2 60

3 84

4 75

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