Stoichiometric Analysis Formal Lab Report

Stoichiometric Analysis Formal Lab Report

I. Purpose- The purpose of this lab is to show stoiciometric reactions and relationships first hand. It also increases our level of understanding about the complicated relationships in chemical reactions and in stoichiometry.

II. Introduction- In chemical reactions and formulas there are various relationships between masses of reactants and products. The study of these relationships is called stoichiometry which is derived from the Greek words stoichein meaning “element” and metron meaning ”measure”. Stoichiometry is helpful in predicting outcomes of reactions or finding out missing parts in reactions. It can also help you determine unknown compounds.

III. Methods- Add a small sample of MnO2 to a dry test tube. Find the mass of this by zeroing a beaker on a scale and placing the tube inside. Place about 2.00 g of KCLOx into the test tube. Record the new mass, and mix the two reactants. Put in test tube clamp at a 45 degree angle. Heat the mixture for about 5 minutes. Allow to cool. Record the new mass. Repeat these steps with the KCLOx/KCLO mixture.

IV. Results-

KCLOx 1. 19.78 g 2. 21.88 g 3. 2.10 g 4. 21.12 g 5. 1.34 g KCL 6. .66 g O2 7. .017 mol KCL 8. .041 mol O2 9. KCLO3 10. 2 KCLO3 ( 2 KCL + 3 O2

KCL/ KCLOx 1. 23.79 g 2. 25.83 g 3. 2.04 g 4. 25.38 g 5. 1.59 g KCL 6. .45 g O2 7. .014 mol O2 8. .009 mol KCLOx 9. 1.10 g KCLOx 10. .539 % KCLOx in mixture

V. Conclusion- This lab showed us how stoichiometry can be used in a real situation to find something out. I think that the purpose of the lab was reached. It was helpful in strengthening my understanding of stoichiometry by using critical thinking to solve a problem. There was plenty of room for error. The results could be thrown off if the error is too great. Technique was needed in making sure the entire sample was reacted and keeping all of it in the test tube.

VI. Questions-

1. The definition of stoichiometry has roots meaning measure and element. In the first reaction you are trying to find the number or measure of an element that is present in a unknown quantity. 2. d 3. Ion charges aren’t a problem in determining mathematical relationships because the anion in the compound will have the same charge regardless of how many O’s are present. 4. The heating process is the same in both reactions because we want the level of decomposition to be consistent. With a different heating method the decomposition could vary and throw off the calculations. 5. The student could be asked to calculate the theoretical yield and compare/ calculate it to the actual yield to find out their error.