Question

$x$ gm of $CaC{O}_3$ was completely burnt in air. The weight of the solid residue formed is 28 g. What is the value of $x$ in grams?

• A. 44
• B. 200
• C. 150
• D. 50

Answer 1

Answer: (D)

50

$CaC{O}_3\to CaO+C{O}_2\left(g\right)$

$1molCaO=1mol$ of $CaC{O}_3$

Molar mass of $CaO=56.1$ g/mol

Molar mass of $CaC{O}_3=100$ g/mol

Mass of $CaC{O}_3$ that produces $28$g of $CaO$

$=(28\ast 100)/56.1=49.9$g