Experiment 2: Reaction Order and Rate Laws Name: Andrew Cordova Lab Partners: None Date of Experiment: February 20th Location: My house Course Number: CHE112 Abstract: This week we experimentally determined the rate constant k for the reaction 2HCl (aq) +Na2S2O3 (aq) → S (s) + SO2 (aq) + H2O (l) + 2NaCl (aq). In order to do this the average reaction time was recorded in seconds during two trials. The data from the experiment shows this reaction is in the first order overall: rate=.47s-1 [HCl]0 [Na2S2O3]1. These findings seem to be consistent with the expected results Experiment: First prepared a well plate with the appropriate amounts of distilled water, HCl, and Na2S2O3 in each well according to the lab manual. The well where the reaction …show more content…
took place was placed over a black ‘x’ on a white sheet of paper. Recorded the time in seconds at the moment the ‘x’ disappeared from view. The experiment was repeated over two trials with various concentrations of HCl and Na2S2O3. Data Table 1. Varying Concentrations of 1.0 M HCl. Concentrations # of drops # of drops # of drops Stock Solution Stock Solution Reaction (after mixing in well) Reaction (after mixing in well) Reaction Time (seconds) Reaction Rate (sec-1) Well # HCl H2O Na2S2O3 HCl Na2S2O3 HCl Na2S2O3 Trial 1 Trial 2 Average C1, D1 12 0 8 1M 0.3M .6 .12 35.1 35.5 35.3 2.8E-2 C2, D2 6 6 8 1M 0.3M .3 .12 45.8 44.4 45.1 2.2E-2 C3, D3 4 8 8 1M 0.3M .2 .12 50.6 52.2 51.4 1.9E-2 Data Table 2. Varying Concentrations of 0.3 M Na2S2O3. Concentrations # of drops # of drops # of drops Stock Solution Stock Solution Reaction (after mixing in well) Reaction (after mixing in well) Reaction Time (seconds) Reaction Rate (sec-1) Well # HCl H2O Na2S2O3 HCl Na2S2O3 HCl Na2S2O3 Trial 1 Trial 2 Average
C4, D4 8 0 12 1M 0.3M .4 .18 25.7 25.1 25.4 3.9E-2 C5, D5 8 6 6 1M 0.3M .4 .09 49.2 51.3 50.3 1.9E-2 C6, D6 8 8 4 1M 0.3M .4 .06 111 125 118 8.5E-3 Calculations and Error: Reaction Concentrations: Table 1 C1,D1 12 drops HCl * 1M / 20 total drops = .6 M C2,D2 6 drops HCl * 1M / 20 total drops = .3 M C3,D3 4 drops HCl* 1M / 20 total drops = .2 M All wells 8 drops Na2S2O3 * .3 / 20 total drops = .12 M Table 2 C4,D4 12 drops Na2S2O3 * .3 / 20 total drops = .18 M C5,D5 6 Na2S2O3 * .3 / 20 total drops = .09 C6,D6 4 Na2S2O3 * .3 / 20 total drops = .06 All wells 8 drops HCl * 1 M / 20 total drops = .4 M Reaction Rate: C1,D1 1/38 = .026 C2,D2 1/50 = .02 C3,D3 1/53 = .019 C4,D4 1/27 = .037 C5,D5 1/65 = .015 C6,D6 1/109 = .0092 Order: HCl .028/.022 = k[.6]m[.12 ]n / k[.3]m[.12 ]n ln(1.27) = m * ln(2) ln 1.3 / ln 2 = m m = .34 m = 0 Na2S2O3 .039/.019 = k[.4]m[.18]n / k[.4]m[.09]n 2.1 = 2n ln(2.1) = n * ln (2) ln2.1/ln2 = n n = 1.1 n = 1 Rate Constant: k = .019/(.4*.09) k = .53 k = .039/(.4*.18) k = .54 k = .0085/(.4*.06) k = 0.35 Average k = .47 s-1 Lab Question 2: k = .300 / (.5*.5) k = 1.2 M/s Discussion and Conclusion: The data from the experiment shows this reaction is in the first order: rate=.47s-1 [HCl]0 [Na2S2O3]1. Photos: Questions: Determine the reaction order for HCl using calculations described in the Background.
Show your work. Note that your answer will probably not be an even whole number as it is in the examples, so round to the nearest whole number. m = 0 *see calculations above Determine the reaction order for Na2S2O3 using calculations described in the Background. Show your work. Note that your answer will probably not be an even whole number as it is in the examples. m=1 *see calculations above Write the specific rate law for the reaction between HCl and Na2S2O3. rate=.47s-1 [HCl]0 [Na2S2O3]1. What is the purpose of holding the initial concentration of one reactant constant during each trial? This process allows us to determine the reaction order. When changing the concentration of the one particular reactant we are able to calculate the order based on the change in reaction rate. This question refers to the example data given below. Using the rate law and the experimental values given below, calculate k. 1.2M/s *see calculations Rate= k [F2] [ClO2] Experiment [F2] (M) [ClO2] (M) Initial rate (M/S) 1 0.5 0.5 0.300
2 0.8 0.8 0.768 3 0.5 0.8 0.480 6. If the decomposition of HBr(g) into H2(g) and Br2(g) is known to be second order with respect to HBr: Write a balanced chemical equation for this reaction. 2 HBr(aq) H2(g) + Br2(l) Write the rate law for this reaction. rate= k [HBr]2 When the concentration of HBr is 2.0 M, the rate of decomposition is 1.58 x 10-2 M/s. Calculate the value and units of the rate constant. 4.0 * 10-3 M-1s-1 What is the rate of this reaction when the concentration of HBr is 0.75 M? 2.3*10-3s-1 References: Brown, Theodore L., H. Eugene LeMay, and Bruce Edward. Bursten.Chemistry: The Central Science. Upper Saddle River, NJ: Prentice Hall, 2000. Print. Hands-On Labs. (2015). HOL Courseware and Resources. Denver, CO. Print, digital, and web formats.
This is because there are more water molecules in a given volume to react with the Alka-Seltzer tablets. However if there are sufficient water molecules to occupy the Alka-Seltzer tablets an increase in the water molecules will not alter the rate of the reaction. This is because the Alka-Seltzer tablets are already working as fast as they can to react with the water. The concentration can be increased by increasing the volume of the water used in the reaction to dissolve the Alka-Seltzer tablets in. To control the... ...
Addition and Subtraction- in that order as well. To explain this, we will solve the problem above:
== == I completed a table to show my results, here is the table: Table 1. Results of different changes of substances Part A Copper (II) Sulfate and Water Reactant description Water (reactant): Color: Colorless Transparency:
and it is necessary for the back of the gas syringe to be taken out,
Investigating the Factors Influencing the Rate of Reaction Between Sodium Thiosulphate and Dilute Hydrochloric Acid
The rate equation is in terms of concentration over time and the reaction rate compares the increase/decrease
Na2S203 (aq) + 2HCl (aq) -> 2NaCl (aq) + H20 (l) + SO2 (g) + S (s)
In the reaction, potassium peroxodisulphate and potassium iodide will be used to provide the peroxodisulphate ions and iodide ions respectively. The ionic formula for the reaction is as follows:
And the symbol equation for it is:. Na2S2O3 + 2HCl, S + SO2 + 2Na + H2O. Before conducting my experiment, I will research into, amongst other things, the factors that affect the rate of a reaction. This is so that I may have enough information to understand the effect of temperature on the rate of a reaction and also gain appropriate understanding to make a suitable prediction as to what the outcome of my experiment will be. Reactions occur when the particles of reactants collide together continuously.
Rate of Reaction - Sodium Thiosulphate and Hydrochloric Acid. Aim Investigation, to find out how the rate of reaction between sodium thiosulphate and hydrochloric acid is affected by changing the concentration. Introduction I must produce a piece of coursework investigating the rate of reaction, and the effect different changes have on them. The rate of reaction is the rate of loss of a reactant, or the rate of development of a product during a chemical reaction. It is measured by dividing 1 by the time taken for the reaction to take place.
Effect of Temperature on the Rate of Reaction between Sodium Thiosulphate and Hydrochloric Acid Investigation Chemical reactions are used in our everyday life, they literally keep us alive. They are used in food, respiration and everywhere else in the environment. A chemical reaction mainly occurs when reactants react together to produce a new product. The speed at which this reaction takes place is called the rate of reaction. The product produced has a number of particles in the solution that has formed from the reactants.
Investigating the Effects of Temperature on the Rate of Reaction between Magnesium and Hydrochloric Acid Introduction Chemical kinetics is the study and examination of chemical reactions regarding re-arrangement of atoms, reaction rates, effect of various variables, and more. Chemical reaction rates, are the rates of change in amounts or concentrations of either products or reactants. Concentration of solutions, surface area, catalysts, temperature and the nature of reactants are all factors that can influence the rate of reaction. Increasing the concentration of a solution allows the rate of reaction to increase because highly concentrated solutions have more molecules and as a result the molecules collide faster. Surface area also affects reaction rate because when the surface area of a reactant is increased, more particles are exposed to the other reactant.
One vital process in the human body observed in chemistry is the idea of chemical kinetics. Chemical kinetics is the study of the rate of reactions, or how fast reactions occur.1 Three factors that affect chemical kinetics are concentration, temperature, and catalysis. As the concentration of a substance increases, the rate of the reaction also increases.1 This relationship is valid because when more of a substance is added in a reaction, it increases the likelihood that the
rate of reaction. To do this I will put a piece of paper with an "X"
t = time, a = volume of reactant, k is a constant of proportionality; x is the order of reaction. Because k is a constant of proportionality 1/t is directly proportional to the rate of reactant. Then to find out the order of reaction in a catalysed system the volume of ammonia molbydate is varied and the concentration of the other reactants kept the same. Thirdly to investigate the activation energies, the concentrations are kept the same and the temperature is varied.