Introduction & Background:

The purpose of this lab is to determine how a reaction between an unknown metal and an acid be used to identify the metal. During the lab, a sample of the unknown metal is reacted with an acid and the hydrogen formed is collected.  The amount of hydrogen collected is calculated from its pressure, volume, and temperature.  From the amount of hydrogen and the mass of the unknown metal sample, an approximation of the atomic weight of the metal can be calculated based on all three stoichiometric possibilities.  To identify an unknown metal reacted with an acid, the released H2 gas is captured in a closed container with known volume and known temperature.  The Ideal Gas Law is then used to calculate the number of moles of hydrogen:

From the number of moles of hydrogen released and applying each of the possible three stoichiometric ratios, three atomic weights can be calculated.  Using the three calculations, a match can be found in the periodic table.