1.00g of mixture of calcium carbonate and calcium oxide liberated 0.33g of carbon dioxide on...

JAMB 1982

1.00g of mixture of calcium carbonate and calcium oxide liberated 0.33g of carbon dioxide on strong heating. The percentage of calcium oxide in the mixture is? (Ca = 40, C = 12, O = 16)

A. 5
B. 15
C. 25
D. 35
E. 50

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Correct Answer: Option C

Explanation

CaCO₃ + CaO \(\to\) 2CaO + 2CO₂

44gm of CO₃ is liberated by 100gm of CaCO₃

0.33gm of CO₂ will be liberated by \(\frac{100}{44}\) x 0.33

= 0.75 of CaCO₃

Amount of CaO = 1 - 0.75

= 0.25

% of CaO = \(\frac{0.25}{1} \times \frac{100}{1}\)

= 25%

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