Question

An experiment is performed to measure the mass percent of caco3(s) in eggshells. Five different samples of caco3(s) of known mass react with an excess of 2. 0mhcl(aq) in identical sealed, rigid reaction vessels. The pressure of the gas produced is measured with a pressure gauge attached to the reaction vessel. Since the reaction is exothermic, the reaction system is cooled to its original temperature before the pressure is recorded. The experimental data are used to create the calibration line below.

Answer 1

The law of conservation of mass states that matter cannot be created or destroyed in a closed system. In the reaction example, the mass of calcium carbonate (CaCO3) before reaction equals the mass of carbon dioxide (CO₂) and calcium oxide (CaO) after, confirming this law.

Step-by-step explanation:

The student's question pertains to the law of conservation of mass as it applies to a reaction involving calcium carbonate (CaCO3). An example is given where heating 10.0 grams of CaCO3 produces 4.4 g of carbon dioxide (CO₂) and 5.6 g of calcium oxide (CaO). To show that these observations align with the law of conservation of mass, one must demonstrate that the mass of the reactants equals the mass of the products.

Using the experimental data provided:

• Mass of CaCO3 (reactant): 10 g
• Mass of CO₂ and CaO (products): 4.4 g + 5.6 g = 10 g

Since the mass before the reaction (10 g of CaCO3) is equal to the mass after the reaction (10 g of combined CO₂ and CaO), the law of conservation of mass is upheld. This fundamental chemical principle states that matter cannot be created or destroyed in a closed system through ordinary chemical reactions or physical changes.