JEE MainChemistrySome Basic Concepts of Chemistry
Thermal decomposition of calcium carbonate produces calcium oxide and carbon dioxide gas. If the volume of carbon dioxide gas produced at STP is 11.35 L , the mass of calcium carbonate decomposed is ____ g . (Given: Molar masses in g mol ⁻¹ : Ca = 40 , C = 12 , O = 16 . Molar volume of gas at STP = 22.7 L )
Correct answer
50
Step-by-step solution
The balanced chemical equation for the thermal decomposition of calcium carbonate is: CaCO ₃(s) CaO (s) + CO ₂(g) Number of moles of CO ₂ gas produced = Volume at STP Molar volume at STP Moles of CO ₂ = 11.35 22.7 = 0.5 mol From the stoichiometry of the balanced equation, 1 mol of CO ₂ is produced from 1 mol of CaCO ₃ . Therefore, moles of CaCO ₃ decomposed = 0.5 mol . Molar mass of CaCO ₃ = 40 + 12 + (3 16) = 100 g mol ⁻¹ Mass of CaCO ₃ decomposed = Moles Molar mass Mass = 0.5 100 = 50 g Answer: 50