# Determine the Reaction Stoichiometry and the Valency of Magnesium

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Objective: To study the quantitative relationship between the amount of the reactants and products of a reaction. 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 amounts of products with given the reactants and percent yield. In this experiment, a known starting mass of magnesium and the measured collection of hydrogen gas will be used to determine the reaction stoichiometry. Magnesium is used to reacts with hydrochloric acid in order to produce…show more content…
And the reaction between magnesium and hydrochloric acid is an exothermic reaction. Since the HCl is added in excess, hence the magnesium is the limiting reactant in this reaction. In this situation, the magnesium is used up completely to react with the excess hydrochloric acid.Based on the quantitative relationship between the amount of the reactants and products of the following equation: Mg + xHCl → MgClx + X/2 H2 A known starting mass of magnesium and the amount of hydrogen gas collected will be used to determine the x value and the valency of magnesium. In this experiment, the volume of unknown marked space in 50cm3 burette determined was5.5cm3. Volume of hydrogen gas was equal to burette marked region minus the burette reading after completion of reaction plus the volume of unknown marked space in 50cm3burette and it was 32.9cm3. From the calculation, the x value in the equation determined was 2.Therefore, the complete equation for magnesium and hydrochloric acid is Mg + 2HCl → MgCl2 + H2. The proportional molecular between Mg and Cl is 1:2.As magnesium is the categorized to the group 2 element in the periodic table which has 2 valence electrons presence in most outer shell. A magnesium atom will lose 2 electrons to form a stable 2+