Experiment on determination of stoichiometry of a reaction | CHEM 1045, Lab Reports of Chemistry

Download Experiment on determination of stoichiometry of a reaction | CHEM 1045 and more Lab Reports Chemistry in PDF only on Docsity! Lab Report Sydney Pelts 10/15/2008 Partner- Linda Robertson 10/22/2008 Instructor- Lucy Liu Experiment 6- Stoichiometry 1. Objective  To determine the stoichiometry of the reaction between sodium hypochlorite (NaClO) and potassium iodide (KI) in aqueous solution. 2. Experimental Data Vol NaClO (mL) Vol KI (mL) Intial Temp. NaClO (C) Initial Temp. KI (C) 45.0 5.00 22.27 20.57 40.0 10.0 21.67 20.66 35.0 15.0 21.66 20.70 30.0 20.0 21.55 20.72 25.0 25.0 21.70 20.76 20.0 30.0 21.31 20.86 15.0 35.0 21.34 20.89 10.0 40.0 21.24 20.90 5.0 45.0 21.17 20.91 3. Sample Calculations This is the method of finding the mole ratio of NaClO. Mole fraction = Volume NaClO Volume NaClO + Volume KI Volume NaClO = 45.0 mL Volume KI = 5.0 mL = 45.0 mL = 0.90 45.0 mL + 5.0 mL 4. Results and Conclusions Mole Fraction NaClO Initial Temp. (C) Final Temp. (C) T (C) 0.90 22.10 24.63 2.53 0.80 21.47 27.83 6.36 0.70 21.37 27.04 5.67 0.60 21.22 26.26 5.04 0.50 21.23 25.31 4.08 0.40 21.04 24.42 3.38 0.30 21.03 23.44 2.41 0.20 20.97 22.51 1.54 0.10 20.94 21.80 0.86 Conclusions: The stoichiometry of any particular reaction must be determined by experiments which measure both the relative amounts and chemical formulas of the reactants and products. In this experiment the reaction between the NaClO and the KI is an exothermic reaction, this caused heat to be given up to the environment causing the temperature to rise. 5. Discussion of Discrepancy and Experimental Uncertainty In this experiment several sources could have caused uncertainty. One would be if there was already KI left on the scale when measuring our amount; this could have thrown off the temperature readings. Also, if we forgot to rinse the temperature probe between measuring the temperature in NaClO and the KI solution. Another factor that could affect uncertainty would be if we did not wait for the temperature probe to fully reach the highest temperature of the reaction between the NaClO and the KI solution. 6. Answers to Questions: a. Stoichiometric coefficient: the coefficient that occurs before a species in a chemical equation to ensure that the equation balances.