Share
Explore BrainMass

Chemical Kinetics

Chemical kinetics is the study of the rates of chemical reactions. It closely examines reaction rates by looking at external variables, such as experimental conditions, and internal variables, such as the formation of intermediates. Although chemical kinetics can be highly theoretical, it also deals with experimental determination of reaction rates through the application of rate laws, and experimentally-derived rate constants. In chemical kinetics, knowing which rate law to apply is heavily dependent on the order of the reaction. This describes the exponent to which the reactant’s concentration in the rate equation is raised to. Consider the following rate equation: r = k[A]^1 [B]^2 where r is the rate of reaction k is the rate constant [A] is the concentration of reactant A [B] is the concentration of reactant B So looking at the above rate equation, we can see that the order of reaction of A is 1, while the order of reaction of B is 2. However, the overall order of reaction is 3, through summing the reaction orders of both reactants. Using the above equation, doubling the concentration of the reactant A, while keeping the concentration of B constant, will double the rate of reaction. Doubling the concentration of B, while keeping the concentration of A constant, will quadruple the rate of reaction. However, doubling the concentration of both A and B, will increase the original reaction rate by eightfold. Thus, understanding Chemical Kinetics is crucial to understanding the rates of chemical processes, and the variables which affect them.

Kinetics in Chemical Reactor

See the attached file. 1. The reversible exothermic water-gas shift reaction (seen in attached file), takes place in an isobaric and adiabatic PFR reactor of V=1m3. Ftot = 100 moles/sec contains 40 mol% H20 and 20 mole % of inert I. The total pressure is 3 bar and the inlet temperature is Tin = 500 k. In parallel the methanatio

Zinc-containing enzyme carbonic anhydrase

(a) The zinc-containing enzyme carbonic anhydrase is present in the red blood cells of humans and catalyses the following physiologically important reaction. Please see the attached document for the reaction. Where the carbon dioxide produced during respiration is converted to hydrogen carbonate, which is very soluble in

Rate Law and Rate Constant

Question 1. Write the rate law and give the rate constant for this reaction. 2 ClO2(aq) + 2 OH^-(aq) ---> ClO-3(aq) + ClO2^-(aq) + H2O(l) The following rate data were collected: Experiment----------[ClO2]---------[OH-]-----------initial rate 1----------------------0.060M-------0.030M--------0.0248 M/s 2------------

Kinetics: Rate Law

i am clarifying this is not an assignemt is just practice questions. It was part of an old test that the teacher gave to us to practice . This are practice questions 1. Calculate deltaH for the reaction P4O10 + 6 PCl3 ----? 10 Cl3PO From P4 + 6 Cl2 -----> 4 PCl3 deltaH = -1225.6 kJ P4 + 5 O2 -----> P4O10 deltaH =

Concentration, Saturation and Vapor Loss of a Gas in Tank

Hello: We are to assume a 129 m3 closed tank. The tank previously contained heptane and therefore has residual vapor. The vapor pressure is given and known as 40 mm Hg The temperature is given as 25 degrees C. 1) Is there a way to determine what the residual concentration of heptane gas would be in this closed con

Firefighter Health

Why are active on-duty firefighters likely to experience the adverse health effects from inhaling 300 ppm of carbon monoxide faster than nonactive off-duty firefighters who inhale the same concentration of the same substance? Explain your answer using the chemicals/process involved.

Review Questions on Kinetics

Please can you provide an explanation for the following questions: For the rate law, Rate = k[A]2[B], which of the following is false about the chemical reaction having this rate law? A) Doubling [A] quadruples the rate. B) The reaction is third order overall. C) The chemical reaction must be: 2 A + B â?' C. D) Do

Finding Rate of Reaction

An enzyme is a large protein molecule (typically with a molar mass greater than 20,000 AMU) that has a structure capable of catalyzing specific biological reactions. In general one or more reactant molecules (called substrates) bind to an enzyme at its "active sites" where the reaction the enzyme is responsible for occurs. The g

Exam Review 2 Questions

Would like to see answers worked out for exam review. Question 1 P(C6H14)/t was found to be -6.2 x 10-3 atm/s for the following reaction: C6H14(g) C6H6(g) + 4H2(g) Determine P(H2)/t for this reaction at the same time. 6.2 x 10-3 atm/s 1.6 x 10-3 atm/s 2.5 x 10-2 atm/s -1.6 x 10-3 atm/s -2.5 x 10-2 atm/s

Gen. chem 2 problems in Kinetics

Please see the attached file for full questions. 1. Consider the following reaction: 2N2O(g) -> 2N2(g) + O2(g) a. express the rate of the reaction with respect to each of the reactants & products. b. In the first 10s of the reaction, .018 mol of O2 is produced in a reaction vessel with a volume of .250L. what is the average

Reaction Kinetics, Rate Laws and Equilibrium

1. The isomerization of cyclopropane to form propene CH3 - CH CH2CH2 is a first-order reaction. At 760 K, 15 percent of a sample of cyclopropane changes to propene in 6.8 minutes. What is the half-life of cyclopropane at 760 K? 2. Consider the two gaseous equilibria (K1 and K2): SO2(g) + ½O2(g) SO3(g)

Determining flow rates- volumetric versus mass flow rates

A flow meter reads 10 liters per minute. The flow is comprised of a 7% solution of water and Chemical A. The % solution is known by Wgt Chemical A/Wgt Chemical A + Wgt of Water Chemical A has a given specific gravity of 2.8 as compared to water...the MW of Chemical A is given as 435 g/mol Therefore, for every 1 liter

Oil Supply and Reserves

1. Just to continue using oil at the current rate (not the projected higher exponential rate), we must discover and add to global oil reserves the equivalent of a new Saudi Arabian supply (the world's largest) every 10 years. Do you believe this is possible? If not, what effects might this have on your life and on the life of a

Reaction Mechanism Based on Rate Expression

Problem: For the reaction: 2H2(g)+2NO(g)--> N2(g)+2H2O(g) The observed rate expression is: rate=k[NO]^2[H2] Which of the following mechanisms is/are consistent with the overall reaction and the rate expression? a. Single step 2H2 + 2NO --> N2 + 2H2O b. Step 1 H2 + NO --> H2O + N (slow) Step 2

Nitrogen Content and Biochemical Oxygen Demand ( BOD )

We have a wastewater source whose flow is 2000 m3 per day; the stated BOD or bio-chemical oxygen demand in that wastewater is given as 5000 mg/l. We are to use urea (NH2)2CO to provide nitrogen to the wastewater in a specific ratio of 100 parts (BOD) to 5 parts(Nitrogen) --- no more or no less. The mass fraction of N in ur

Reaction Kinetics : Calculating a Rate Constant

The following data were acquired in an iodination experiment involving acetone. Trial Volume of 0.0010 ( ) Volume of 0.050 ( ) Volume of 1.0 acetone ( ) Volume of water ( ) Temperature ( ) Reaction time ( ) A 5.0 10.0 10.0 25.0 25.0 130 B 10.0 10.0 10.0 20.0 25.0 249 C 10.0 20.0 10.0 10.0 25.0 128 D 10.0 10.0 20

Reaction Kinetics : Absorbance of Crystal Violet

The question is : What is happening to the crystal violet concentration as the absorbance decreases? Choices: a) increases b) decreases c) nothing happens to the crystal violet concentration CRYSTAL VIOLET(1) A KINETICS STUDY -----------------------------------------------------------------

Reaction Kinetics Lab : Hydrolysis of Aspirin

Please see the attached files for the fully formatted problems. Use the data attached to work out the order of reaction in terms of rate (calculate the error associated with the determined value) Discuss the MECHANISM, HYBRIDIATION, BOND LENGTHS and REACTION NAME of the process discussed.

Rate Laws, Rate Constants and Reaction Orders

Please see the attached file for the fully formatted problems. Question 1 Consider the reaction whose rate at 25 was measured using three different sets of initial concentrations as listed in the following table: 1 0.40 0.010 1.9×10^3 2 0.40 0.020 3.8×10^3 3 0.80 0.010 7.7×10^3 What is the rate law

Calculating Rate Laws

Please see the attached file for the fully formatted problems. For the reaction , the initial reaction rate was measured for various initial concentrations of reactants. The following data were collected: Trial ( ) ( ) ( ) Initial Rate ( ) 1 0.10 0.10 0.10 2 0.10 0.10 0.30 3 0.20 0.10 0.10 4

Reaction Kinetics : Reaction Orders from Concentration and Reaction Times

The following data were acquired in an iodination experiment involving acetone. Trial Volume of 0.0010 ( ) Volume of 0.050 ( ) Volume of 1.0 acetone ( ) Volume of water ( ) Temperature ( ) Reaction time ( ) A 5.0 10.0 10.0 25.0 25.0 130 B 10.0 10.0 10.0 20.0 25.0 249 C 10.0 20.0 10.0 10.0 25.0 128 D 10.0

Concentration and Reaction Order

Solution to be listed in Excel Graphs The initial speed of formation of a substance X depends on the concentration as it follows: C x*103 [M] 5.0 8.2 17 30 Vx, 0*107 [Ms-1] 3.6 9.6 41 130 Find the order of the reaction and the constant of speed. Solution: Let the order of reaction be "m" and constant of speed k. The

Rate Constant for Reverse Reaction

The rate constant for the elementary reaction is 7.1 109/M·s at 25°C. 2 NO(g) + O2(g) 2 NO2(g) What is the rate constant for the reverse reaction at the same temperature?

Chemical Kinetics, Experimental Measurements and Rate Law

1) Explain the concept of chemical kinetics and the various factors that influence reaction states. 2) Relate experimental measurements to reaction rates and the rate laws. 3) Determine the order of reaction, the rate law, the rate constant, and the rate of concentrations. 4) Solve first-order rate problems.

Orders of Reaction

The rate of the following reaction in aqueous solution is monitored by measuring the number of moles of Hg2Cl2 that precipitate per liter per minute. The data obtained are listed in the table. 2HgCl2 + (C2O4^2-) ----> (2Cl^-) + 2CO2 (g) + Hg2Cl2 (s) Experiment [HgCl2],M ([C2O4]^2-),M Initial rate,m

The half-life for the first-order decomposition of sulfuryl chloride

The half-life for the first-order decomposition of sulfuryl chloride at 320 degrees Celsius is 8.75 h. SO2Cl2 (g) -----> SO2 (g) + Cl2 (g) (a) What is the value of the rate constant k, in s^-1? (b) What is the pressure of sulfuryl chloride 2.52 h after the start of the reaction, if its initial pres

Reaction Rates

The rate of the following reaction in aqueous solution is monitored by measuring the rate of formation of (I3^-). The data obtained is listed in the table. (S2O8^2-) + (3I^-) ----> (2SO4^2-) + (I3^-) Experiment ([S2O8]^2-), M ([I]^-),M Initial rate, M s^1- 1 0

Concentration

The smog constituent peroxyacetyl nitrate (PAN) dissociates into peroxyacetyl radicals and NO2 (g) in a first-order reaction with a half-life of 32 min. If the initial concentration of PAN in an air sample is 5.9 x 10^14 molecules/L, what will be the concentration 1.05 h later? (in molecules/L)