Use the equation given to determine the "theoretical" values of g M / moles H2 (note that "M" is simply the metal, which is either La, Ba, Mn, or Pb). The equation is g metal / moles H2 = mass of metal / (moles H2/moles metal). The unknowns are each one of the following metals - La, Ba, Mn, Pb. Calculate the theoretical values of g M/ moles H2 for each of these metals. In each case, the metal chloride product is identified to the right to help determine the ratio of moles M / moles H2 produced.
g / La moles H2 - ? (LaCi 3 is produced)
g / Ba moles H2 - ? (BaCi 2 is produced)
g / Mn moles H2 - ? (MnCI2 is produced)
g / Pb moles H2 - ? (PbCI 2 is produced)
Write the balanced chemical equation for the reaction between the metals given and HCl (for example, La + HCl > LaCl3 + H2this equation needs to be balanced first). From the balanced chemical equation, you can determine the moles of H2/moles La. Remember that the number of moles is just the number of the coefficient in from of the molecule. For example, if you have 3H + 2O ---> 4H2O, there are 3 moles of H, 2 moles of O, and 4 moles of H2O in that equation. The mass of the metal (La) is just the atomic mass of La obtained from the periodic table.