Stoichiometry is the study of the quantitative, or measurable, relationships that exist in chemical formulas and also chemical reactions. In this experiment hydrogen gas will be produced from the reaction of a known mass of magnesium metal with an excess of hydrochloric acid. The theoretical number of moles of hydrogen gas may be calculated using stoichiometry and the balanced chemical equation. The theoretical volume of hydrogen gas may then be determined from the previously determined number of moles of gas by rearranging the ideal gas law to solve for volume at the experimental conditions of temperature and pressure. A comparison to the experimental volume of hydrogen gas obtained from the experiment is then made. The amount and percent errors will demonstrate the experimenter’s accuracy and precision.
Results and Discussion
When gases are collected by water displacement the volume of gas above the water includes not only the gas being bubbled through the water but also water vapor. Therefore, the total pressure in the eudiometer is due to the gas pressure plus water vapor pressure. The pressure due to water vapor is directly proportional to the temperature of the water. From this we were able to see how much Magnesium and H2 gases reacted with each other along with the H2O and we were able to figure out the HCl: Mg ratio with all the data we collected. The experiment although at first the magnesium was dissolving to fast turned out perfect after the second try.
Questions and Answers