Chem Lab 2

Chem Lab 2 - Kahl INTRODUCTION The purpose of this lab was...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Kahl INTRODUCTION The purpose of this lab was to examine the stoichiometric properties of a reaction and then, by manipulating the amounts of reactants, determine which was the limiting reactant. The two reactants used in this experiment were aqueous solutions of one molar calcium chloride and two and a half molar sodium hydroxide. The reaction of these two ionic compounds yields solid calcium hydroxide and aqueous sodium chloride, as demonstrated by the equation below: CaCl 2(aq) + 2 NaOH (aq) → Ca(OH) 2(s) + 2 NaCl (aq) Based on the equation, it can be deduced that for every mole of calcium chloride added, two moles of sodium hydroxide will have to be added in order for the reaction to proceed to completion. However, it is very rare that an experiment will use the perfect amount of reactants in the same stoichiometric ratio as their formula indicates. This means that there will be more of one reactant than needed to react with the other. As a result, the amount of product will be limited to the amount of the other reactant present. Thus, the left-over reactant is deemed the excess reagent and the consumed reagent is known as the limiting reagent. Without increasing the excess reagent, increasing the mass of the limiting reagent will allow the mass of the product to increase. Assuming a constant excess reagent, increasing the mass of the limiting reagent will continue to cause an increase in the mass of the product until the molar ratio of the limiting reagent to the excess reagent equals their stochiometric ratio. If the mass of the limiting reagent is increased passed this point, the roles switch. The limiting reagent becomes the excess reagent and what was the excess reagent becomes the limiting reagent. In the lab, varying amounts of NaOH were added to a fixed amount of CaCl 2 . Because the molarity of both reactants were known, the moles of each substance could be calculated volumetrically. Using the number of moles of each substance, the theoretical yield of Ca(OH)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/07/2011 for the course CHEM 101 taught by Professor Multipleprofs during the Fall '07 term at Drexel.

Page1 / 4

Chem Lab 2 - Kahl INTRODUCTION The purpose of this lab was...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online