Chemical Kinetics Experimental Results
CHEMICAL KINETICS
RESULTS AND DISCUSSION
The balanced equation of the reaction between sodium thiosulfate and Hydrochloric acid is:
S2O32- (aq) + 2 H+ (aq) SO2 (g) + S (s) +H2O (l)
Using beakers with the same diameter was very important in conducting the experiment. If different sizes were used, the visibility of the “x” on the paper beneath the beaker could disappear from view too early or too late than the hypothetical time depending on the depth of the solution. It was also significant to use the same timer in recording the time of reaction because different timers have different accuracy and response and may therefore invalidate the resulting observed time of reaction. Having a single person to judge the “end” of the reactions was important because people have different judgments. One person would say that the reaction was over while another one would not which would result to a larger percentage of error.
Adding the acid last in runs 1-3 was needed because HCl was the controlled reactant. In runs 4-6 Na2S2O3 was added last because it served as the controlled reactant for the same reason- that it was the controlled reactant in the last three runs.
The order of the reaction with respect to S2O32- was 1 while that of respect to H+ was 0. This clearly explains why there is only a minimal deviation in the rate of reaction in runs 4-6 when the amount of Na2S2O3 was maintained constant and the HCl amount was varied. The complete solution can be found in the Sample Calculations page.
Temperature-dependence of Reaction Rate: The Arrhenius Equation
Based on the data obtained, temperature is directly proportional to the rate of reaction. As the temperature increases, the rate of reaction also increases.
The average rate of a chemical reaction over a certain interval of time is equal to the change in concentration of a reactant or product that occurs during that time divided by the time. Since rate is proportional to (1/t), then (1/t) is also
RESULTS AND DISCUSSION
The balanced equation of the reaction between sodium thiosulfate and Hydrochloric acid is:
S2O32- (aq) + 2 H+ (aq) SO2 (g) + S (s) +H2O (l)
Using beakers with the same diameter was very important in conducting the experiment. If different sizes were used, the visibility of the “x” on the paper beneath the beaker could disappear from view too early or too late than the hypothetical time depending on the depth of the solution. It was also significant to use the same timer in recording the time of reaction because different timers have different accuracy and response and may therefore invalidate the resulting observed time of reaction. Having a single person to judge the “end” of the reactions was important because people have different judgments. One person would say that the reaction was over while another one would not which would result to a larger percentage of error.
Adding the acid last in runs 1-3 was needed because HCl was the controlled reactant. In runs 4-6 Na2S2O3 was added last because it served as the controlled reactant for the same reason- that it was the controlled reactant in the last three runs.
The order of the reaction with respect to S2O32- was 1 while that of respect to H+ was 0. This clearly explains why there is only a minimal deviation in the rate of reaction in runs 4-6 when the amount of Na2S2O3 was maintained constant and the HCl amount was varied. The complete solution can be found in the Sample Calculations page.
Temperature-dependence of Reaction Rate: The Arrhenius Equation
Based on the data obtained, temperature is directly proportional to the rate of reaction. As the temperature increases, the rate of reaction also increases.
The average rate of a chemical reaction over a certain interval of time is equal to the change in concentration of a reactant or product that occurs during that time divided by the time. Since rate is proportional to (1/t), then (1/t) is also