Laws of chemical combination: conservation of mass, constant proportions
Atoms and Molecules (School Level) · Chemistry
Study notes
10 g of calcium carbonate is heated strongly; 5.6 g of calcium oxide remains. What mass of carbon dioxide is produced? Step 1: Reaction: CaCO₃ → CaO + CO₂. Step 2: Law of conservation of mass: total mass before = total mass after. Step 3: 10 g = 5.6 g + mass(CO₂). Step 4: mass(CO₂) = 10 − 5.6 = 4.4 g. No mass is lost — the 'missing' 4.4 g escaped as gas.