Date Performed: 10/16/09 Name: Rachael Harris
Date Submitted: 10/23/09 Partner: Halie Sklanka
Stoichiometry; Method of Continuous Variations
Objective
To determine the stoichiometry of the reaction between sodium hypochlorite (NaClO)
and potassium iodide (KI) in aqueous solution.
Experimental Data
Vol. of NaClO
(mL)
Vol. of KI
(mL)
Initial temp.
Of NaClO (°C)
Initial Temp.
Of KI (°C)
Final Temp.
(°C)
45.0 5.00 21.62 22.04 24.40
40.0 10.0 22.22 22.12 26.94
35.0 15.0 23.14 22.37 26.73
30.0 20.0 22.88 22.15 26.60
25.0 25.0 22.52 21.87 26.25
20.0 30.0 21.56 21.51 26.12
15.0 35.0 22.14 21.82 25.99
10.0 40.0 21.93 21.73 24.01
5.00 45.0 22.02 21.81 23.00
Sample Calculations
Mole fraction NaClO = Number of NaClO moles or Vol. NaClO
Number of NaClO moles + Number of KI moles Vol. NaClO + Vol. KI
- Mole fraction NaClO = 45.0 mL = 0.900 mol
45.0 mL + 5.00 mL
Average initial T = T1V1+T2V2
V1+V2
-Average initial T = (21.62°C)(45.0mL) + (22.04°C)(5.00mL) = 21.7°C
50.0mL
ΔTT = TFinal - TInitial
- ΔTT = 24.40°C – 21.66°C = 2.74°C
