To determine the carbonation degree of materials used in mineral carbonation experiments, a fast, simple, and sufficiently accurate method is required. For this purpose, a method based on the reaction between carbonates and hydrochloric acid was developed. It was noted that this method could also be used to teach undergraduate students some basic concepts in thermodynamics and inorganic chemistry. When the mass of a sample exposed to a HCl solution is measured, the carbonation degree of the sample can be calculated from the difference between the initial pressure and the final pressure in a sealed container using the ideal gas law. The equipment and methods are presented in detail together with considerations that take into account the heat of reaction, H[subscript 2]O release, and measurement accuracy, all of which can be incorporated into an interesting and informative experiment in applied chemistry. (Contains 5 figures.)