An X gram of calcium carbonate was completely burnt in air. The weight of the solid residue formed is 28 g. what is the value of X in grams

Explanation

Calcium carbonate decomposition: When calcium carbonate (CaCO₃) is heated strongly in air, it decomposes according to the following equation: CaCO₃ (s) → CaO (s) + CO₂ (g)Mass conservation: According to the law of conservation of mass, the total mass of the system remains constant before and after the reaction. Therefore, the mass of the solid residue (CaO) formed will be equal to the mass of calcium carbonate decomposed minus the mass of carbon dioxide released.Calculating X:o We know the mass of the solid residue (CaO) is 28 grams.o The molar mass of CaCO₃ is 100.09 g/mol, and the molar mass of CaO is 56.08 g/mol.o Let Y be the moles of CaCO₃ decomposed.Setting up the equation based on mass conservation:Mass of CaO = Mass of CaCO₃ - Mass of CO₂28 g = Y * 56.08 g/mol - Y * (100.09 g/mol - 56.08 g/mol)Solving for Y:Y ≈ 0.5 molesNow, calculate the mass of CaCO₃ (X) using the number of moles and molar mass:X = Y * Molar mass of CaCO₃X ≈ 0.5 moles * 100.09 g/molX ≈ 50.045 gRounding and choosing the answer: Since the question asks for the value of X in grams, we can round the answer to the nearest whole number, which is 50 g. Therefore, option d. 50 is the correct answer.I hope this explanation clarifies the reasoning and calculation steps involved in determining the value of X. Feel free to ask if you have any further questions!