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  • an impure sample of sugar is burnt and it gives 134.4L of carbon dioxide at STP. If the sample weighs 513g, what is % purity of the sample?

an impure sample of sugar is burnt and it gives 134.4L of carbon dioxide at STP. If the sample weighs 513g, what is % purity of the sample?

Answers (1)

As we learnt

Dalton's Atomic Theory -

Chemical reactions involve reorganization of atoms. Atoms are neither created nor destroyed in a chemical reaction.

- wherein

CaCO_{3}\rightarrow CaO + CO_{2}

The number of atoms on both sides of the equation is the same

C_{12}H_{22}O_{11} + 12O_{2} \rightarrow 12CO_{2} +11H_{2}O

By Dalton's Atomic Theory, the atoms are neither created nor destroyed

\therefore moles of  C_{12}H_{22}O_{11}

 \\*= \frac{1}{12}\times (moles\;of\;CO_{2}) \\*= \frac{1}{12}\times \frac{134.4}{22.4} \\*= \frac{1}{12}\times 6 = 0.5 

molar mass of  C_{12}H_{22}O_{11} = 513g

% purity = \frac{0.5\times513}{mass\;of\;sample} = \frac{0.5\times513}{513}\times 100 = 50\%

\therefore Solution is B


Option 1)

25

This is incorrect.

Option 2)

50

This is correct.

Option 3)

75

This is incorrect.

Option 4)

100

This is incorrect.

Posted by

Ankit Dutt

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