February 28th, 2013
Abstract: The reactions of the Sodium Hydroxide and two acids, Hydrochloric Acid and Sulfuric Acid were performed. The heat given off by these two reactions was used to determine the stoichiometric ratio and the limiting reactants in each experiment.
Introduction: Coefficients in a balanced equations show how many moles of each reactant is needed to react with each other and how many moles of each product that will be formed. Stoichiometry allows us to calculate the amount of reactants needed and also the amount of product. The major basis of stoichiometry is formed by the law of definite proportions, which states that a chemical compound always contains the exact proportion of elements by mass. This is also the heart of balancing chemical equations.
The coefficients of a balanced equation can also be thought of as the ratios in which the reactants combine. In the chemical equation A+ B→ AB the coefficients tell us that for every one mole of reactant “A” one moles of reactant “B” are needed and used to produce the product “AB”. If two moles of “A” was present and only one mole of “B” the excess mole of “A” would have nothing to react with. In this reaction “B” would be the limiting reactant. The reaction is limited due to “B” because once “B” is all used up, the reaction will stop, and there would be an excess of unused “A”.
The progress of a reaction can be measured by the heat energy that is given off. Exothermic reactions give off heat and therefore an increase in temperature also occurs. The reaction between an acid and a base is also known as neutralization, and is usually an exothermic reaction. When reactants are combined at stoichiometric ratios the reaction is able to be completed and would exert the most heat energy. The purpose of this lab was to carry out the reaction between a basic solution of Sodium Hydroxide with Hydrochloric acid, and also the reaction of Sodium Hydroxide with Sulfuric Acid to