Download Stoichiometry of Sodium Hypochlorite and Potassium Iodide Reaction and more Lab Reports Chemistry in PDF only on Docsity! Date Performed: 5-30-08 Name: Danielle Brandibur Date Submitted: 6-2-08 Partner Name: Harry Moore Stoichiometry I. Objective: The objective of this lab is to determine the stoichiometry of the reaction between Sodium (NaClO) and potassium iodide (KI) in and aqueous solution. II. Experimental Data: Volume NaClO (mL) Volume KI (mL) Initial Temp. NaClO (°C) Initial Temp. KI (°C) Final Temp. (°C) 45.0 5.0 23.64 21.12 26.55 40.0 10.0 23.25 22.12 29.86 35.0 15.0 23.31 22.35 29.39 30.0 20.0 23.28 22.43 28.34 25.0 25.0 24.14 23.05 27.93 20.0 30.0 23.77 22.81 26.75 15.0 35.0 23.81 22.83 25.81 10.0 40.0 23.75 23.24 25.10 5.0 45.0 24.09 22.95 23.77 III. Sample Calculations: A. Weighted Temperature: Tinitial = T1V1+T2V2/(V1+V2) Tinitial = ((23.64°C)(45.0mL NaClO)+(21.12°C)(5.0mL KI))/(45.0mL+5.0mL) Tinitial = 23.4°C B. Mole fraction: Mole Fraction= Volume NaClO Volume NaClO+Volume KI Mole Fraction= 40mLNaClO 40mLNaClO+10mLKI Mole Fraction= 0.8 moles Mole fraction of NaClO = 0.8 Mole fraction of KI = 1-0.8 = 0.2 aNaClO + bKI →products a/b = mole fraction of NaClO/mole fraction of KI a/b = 0.8/0.2 = 4.0 moles of NaClO/mole of KI 4 = 4 1=1 4NaClO + KI → products IV. Results and Conclusions Volume NaClO (mL) Volume KI (mL) Initial Temp. NaClO (°C) Initial Temp. KI (°C) Initial Temp. (°C) Final Temp. (°C) ∆T (°C) Mole fraction NaClO Mole fraction KI 50.0 0.0 23.64 21.12 23.64 23.64 0.00 1.0 0.00 45.0 5.0 23.64 21.12 23.39 26.55 3.16 0.90 0.10 40.0 10.0 23.25 22.15 23.03 29.86 6.83 0.80 0.20 35.0 15.0 23.31 22.35 23.02 29.39 6.37 0.70 0.30 30.0 20.0 23.28 22.43 22.94 28.34 5.40 0.60 0.40 25.0 25.0 24.14 23.05 23.60 27.93 4.33 0.50 0.50 20.0 30.0 23.77 22.81 23.19 26.75 3.56 0.40 0.60 15.0 35.0 23.81 22.83 23.12 25.81 2.69 0.30 0.70 10.0 40.0 23.75 23.24 23.34 25.10 1.76 0.20 0.80 5.0 45.0 24.09 22.95 23.06 23.77 0.71 0.10 0.90 0.0 50.0 24.09 22.95 21.12 21.12 0.00 0.00 1.00 The stoichiometric coefficients calculated were determined by the maximum heat released. The maximum heat was released when the mole fraction of NaClO was around 0.80. I obtained this number by drawing diagonal lines on my graph and then drawing a line down from where the two lines intersected to obtain 0.80. By plugging this number into the equations given in class, it is possible to determine that 1-0.80 = 0.20, and thus the mole fraction of KI, when the mole fraction of NaClO is 0.80, is 0.20. This means that the mole ratio is 0.80/0.20 and thus the coefficient ratio is 4/1. V. Discussion of Experimental Uncertainty Although uncertainty was not calculated in this lab, it is important for us to remember that there was ±0.01g uncertainty in the balance when we weighed the KI, and there is ±0.05mL in the graduated cylinder whenever we measured the volume of a liquid such as the bleach. There is also a chance that my partner and I had measurements that were slightly off when measuring the amounts of each thing to make the 0.400M solutions, and if those were off by even a little then all of the measurements for temperatures could be off by a little bit too. There were a lot of places for error in this lab because there was a lot of measuring. VI. Answers to Questions
