Experiment 3

Reactions Taking Place

2KClO3 (s) → 2KCL (s) + 6O (g)

Calculations

A: Mass of oxygen lost becomes moles of Oxygen. KCl residue becomes moles of KCl. find moles of K and moles of Cl. take these three knwon mol values and do the empirical formula B: take mass of oxygen loss, convert to mol. convert to mol of KCl03. 2 mol KClO3=6 mol O. Take mol of KClO3, convert to g. find % mass.

Name of Experiment

Analysis of a Mixture

Suppose in part a KClO3 had water. how'd this affect ratio of O to Cl

Initial mass of KClO3 increaes. KClO3 is heated and the percieved mass difference will be greater due to the fact mass of oxygen and mass of water is lost. This will result in a greater mass of oxygen gas evolved and a greater number of oxygen atoms evolved. Cl atoms stays constant. so O: Cl increases.

MnO2

Manganese Dioxide

How would part a results be different if some of the KCl vaporized

Mass lost from KCl would be percieved as mass lost from Oxygen. So mass of oxygen increases. moles of oxygen goes up. changes ratio in favor of O.

KClO3

Potassium Chlorate

KCl

Potassium Chloride

Background

Stoich relates to the moles and mass relations of different chemical compounds in a chemical reaction. Part A: Only potassium chlorarte is heated; by measuring the amount of oxygen gasreleased from the decomposition of KCl, every other part of KClO3 will be found. Part B: Mixture of KClO3 and KCl. amount of KCl is found. MnO2 is a catalyst, mass stays constant. it lowers activation energy

Key Procedure Steps

Tilt the tube at 45 degrees. increases surface area of the solution inside, gas reaches the surface easier and at a shorter distance. The solution is exposed to more air. More of the substance reacts at once with higher surface area and less depth A: Heat KClO3 in the first step in order to drive off oxygen, gives us mass of KCl. stoich your way to find empirical formula B: Heat to evolve off oxygen again. Use that known mass of oxygen to find moles of KClO3 present. stoich to find % mass in original compound Let test tube cool to prevent convecton currents

Errors

entire of oxygen could not have been evolved. oxygen atoms could be too low. messes up the stoich convection currents in part b. tube could have been hot when it was heated.

Equipment Set Up

Ring Stand w/ Utility Clamp Bunsen Burner under Test tube at 45 degree angle. glass wool at top

Objective

To determine the original amount of potassium chlorate in a potassium chlorate-potassium chloride mixture by measuring the oxygen lost from decomposition

Catalyst

a substance that increases the rate of reaction without being consumed in the reaction itself