Question

Caco3 decomposes to give cao and co2 if the masses of cao and co2 are 5.6g and 4.4g respectively by heating 12 g of an impure caco3 sample then the % impurity of the sample will be

Answer 1

I am not exactly correct but I think it can be the answer.

Ans. Impurity obtained = 12 - (5.6+4 4)
= 12 - 10
= 2g

Thus, %age impurity = (2/12)×100
= 100/6
= 16.67 %




hope it helps..........

Answer 2

Answer: 16.6%

Explanation:-

$CaCO_3\rightarrow CaO+CO_2$

From the balance chemical equation:

100 g of $CaCO_3$ decomposes to give 56 g of $CaO$

Thus 12 gram  $CaCO_3$ decomposes to give=$\frac{56}{100}\times 12=6.72g$ of $CaO$

Thus theoretical yield of $CaO$ is 6.72 g.

But Experimental yield is 5.6 g.

${\text {percentage purity}}=\frac{\text {Experimental yield}}{\text {Theoretical yield}}\times 100\%$

${\text {percentage purity}}=\frac{5.6g}{6.72g}\times 100\%=83.3\%$

Thus percentage impurity=$(100-83.3)\%=16.6\%$