To study the quantitative relationship between the amount of reactants and products of a reaction ( that is how many moles of A react with a given mol of B). A known starting mass of magnesium and the measured collection of hydrogen gas will be used to determine the reaction stoichiometry and the valency of magnesium
Introduction
Stoichiometry is the study of the quantitative relationship between amounts of reactants and products of a reaction. Stoichiometry can be used to calculate the amount of a product formed when given the reactants and a percentage yield. In the case of this experiment, a known starting mass of magnesium ribbon and the amount of collected hydrogen gas will be used in order to determine the reaction stoichiometry
Magnesium is used to react with hydrochloric acid in order to produce hydrogen gas. One of the purposes of this experiment is to determine X in the equation below
The mass of the magnesium used is measured before the use in the experiment via an analytical balance. The known amount of magnesium is then reacted with excess hydrochloric acid which causes the magnesium to be the limiting agent in this particular reaction. The amount of HCl used is in excess in order to ensure that the magnesium reacts completely. Hence, the formation of the products , MgCl and H2 are dependant on the amount of magnesium used. By comparing the amount of hydrogen gas produced with the amount of magnesium used, we are able to determine the value of X
Apparatus
Burette(50cm3), pipette(25cm3), retort stand, analytical balance, watch glass, beaker(500cm3), gauze, funnel, glass rod, thermometer
Materials
Magnesium ribbon, 0.5M HCl
Results
Mass of magnesium ribbon used (g)
0.0143
Initial reading of burette (mL)
21.50
Final reading of burette (mL)
24.60
Volume of unmarked space (mL)
3.5
Total volume of H2 collected (mL)
28.9
Calculation
Mole of magnesium = = 5.958 x 10-4 mol
Actual mol of