Question

A 100 gram calcium carbonate on strong heating produces 20 L of carbondioxide at STP. Calculate the actual weight of calcium carbonate present in the sample and also percentage impurity ​

Answer 1

Explanation:

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CHEMISTRY

50 g of an impure calcium carbonate sample decomposes on heating to give carbon dioxide and 22.4 g calcium oxide. The percentage purity of calcium carbonate in the sample is:

December 27, 2019avatar

Poulomi Mahima

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ANSWER

CaCO

3

⇌

Δ

CaO+CO

2

Let pure sample of CaCO

3

=x grams

Mass of CaO produced after decomposition =22.4 g

Molar mass of CaCO

3

=100 g/mol

and, Molar mass of CaO=56 g

If 100% is pure, then

100 g CaCO

3

⟶56 g of CaO

Also,y g of CaCO

3

⟶22.4 g of CaO

Dividing these two,

y

100

=

22.4

56

y=40 grams

∴ Percentage of purity =

Totalmassofimpure

Massofpuresample

×100=

50

40

×100=80%

just write 100 instead of 50 and 20 l