Question

Calculate the mass of $C{O}_2$ produced by decomposing 40 g of 20 % pure limestone.

• A. 8 g
• B. 4.48 g
• C. 3.52 g
• D. 17. 6 g

Answer 1

The correct option is C 3.52 g

$CaC{O}_3\to CaO+C{O}_2$
Mass of 20% pure $CaC{O}_3$ = 20 % $\times$40 g = 8 g
Moles of $CaC{O}_3=\frac{\text{given mass}}{\text{molar mass}}=\frac{8}{100}=0.08$ moles
As per the reaction,
1 mole of $CaC{O}_3$ decomposes to give 1 mole of $C{O}_2$ gas
0.08 mole of $CaC{O}_3$ will give 0.08 mole of $C{O}_2.$
mass of $C{O}_2$ produced = $0.08\times 44$ = 3.52 g