Decomposition of Bleach Essay Example for Free

Decomposition of Bleach Essay In this experiment, the rate of decomposition is calculated by measuring the volume of the product gas using water displacement. The reactant used is household bleach, which contains 5 to 6% of NaClO. The decomposition can be stated in this following equation: 2 ClO- (aq) 2 Cl- (aq) + O2 (g) To measure the rate of decomposition, a catalyst is needed to fasten the reaction. A suitable catalyst is Co2O3, which is produced from mixing Co(NO3)2 and bleach. The reaction can be described as follows: 2 Co2+ (aq) + ClO- (aq) + 2H2O (l) Co2O3 (s) + 4 H+(aq) + Cl-(aq) Purpose The objective of this experiment is to determine the rate of decomposition of bleach by measurement of gas production at several different temperatures. Hypothesis The decomposition rate will increase if the surrounding temperature increases. If the surrounding temperature increases by 10C, the reaction rate will double. If the temperature decreases by 10C, then the reaction rate will decrease by half. Materials * Household Bleach * Co(NO3)2 solution * Erlenmeyer flask * Stopper and tube * Ring stand * Burette * Graduated cylinder * Thermometer * Burette clamp Procedure Refer to lab instruction sheet Decomposition of Bleach Data Table 1 Accumulation of Oxygen at Room Temperature (24C) Time Interval (s) Volume of Gas (mL) Time Interval (s) Volume of Gas (mL) 30 3.5 210 29.9 60 9.1 240 34.3 90 13.4 270 38.3 120 18.0 300 42.0 150 20.8 330 44.5 180 25.9 360 50.1 Table 2 Accumulation of Oxygen at 10C above Room Temperature (34C) Time Interval (s) Volume of Gas (mL) Time Interval (s) Volume of Gas (mL) 30 8.1 180 37.5 60 13.9 210 41.3 90 20.4 240 45.4 120 26.0 270 49.4 150 31.8 \ Table 3 Accumulation of Oxygen at 10C below Room Temperature (14C) Time Interval (s) Volume of Gas (mL) Time Interval (s) Volume of Gas (mL) 60 0 900 27.2 120 0 960 29.5 180 0 1020 31.9 240 1.8 1080 33.5 300 4.0 1140 36.0 360 6.5 1200 38.0 420 8.9 1260 40.5 540 11.8 1320 42.1 600 13.2 1380 44.1 660 15.6 1440 45.6 720 18.1 1500 47.5 780 21.0 1560 49.6 840 23.0 1579 50.0 Analysis Calculations: Reaction Rate = Reaction rate at room temperature = = 0.14 mL O2 / s Reaction rate at 10C above room temperature = = 0.17 mL O2 / s Reaction rate at 10C below room temperature = = 0.036 mL O2 / s Table 4 Rate of Decomposition of Bleach Surrounding Temperature (C) Reaction Rate (mL/ s)