Question

(4 pts) Consider the following chemical reaction: CuSO4 (s) + heat → CuO (s) + S03 (g) Design an experiment in which you use this chemical reaction to test the law of mass conservation.

Answer 1

A possible experiment would be the following:

In a closed vessel, equipped with a tube that allows the generated gas to bubble in a MgCl₂ solution, add a known mass of CuSO₄. Then heat it carefully, to induce the decomposition the formed CuO will remain as a solid in the vessel, while the gaseous SO₃ will bubble in the solution, forming the insoluble MgSO₃. The mass of CuO can be easily determined by weighting, while the solid MgSO₃ precipitate can be filtered and dried to determine its mass, which is directly related to the mass of SO₃ formed by the decomposition. In this way you can obtain the masses of the three species involved and thus test the law of mass conservation.