To identify an unknown metal, the hydrogen formed after reacting it with an acid is measured. The temperature, volume, pressure, and the unknown metal’s mass can be calculated from the hydrogen produced from the reaction to find the atomic weight of the metal. To perform this lab, a piece of an unknown metal was placed into a flask containing hydrogen chloride placed in a water bath and the flask was plugged with a stopper. The stopper was connected to a pressure sensor and temperature sensor. As the flask was kept in a water bath, the temperature was measured along with the volume, and pressure. After the reaction took place, the number of moles of hydrogen produced was calculated from the data collected and all three atomic weights were found from this information. The possible unknown metal weights were then used to determine the actual unknown metal used in the experiment.