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Chemical Kinetics

Rate Constant

For the reaction 3 A(g) + 2 B(g) yields 2 C(g) + 2 D(g) The following data were collected at constant temperature. Determine the rate law for this reaction and the value of the rate constant. Trial Initial [A] mol/L Initial [B] mol/L Initail rate mol/L min 1 0.200 0.100

Rate of reactions

1. The numerical value of the rate constant for the gaseous reaction 2N2O5 reacts to form 4No2 + O2 was found to be 5.80 times 10 exp -4. The initial concentration of N2O5 was 1.00 mol/L. Assuming all measurements are recorded in seconds, determine the time required for the reaction to be 60% complete. 2. Re

A grain sample was found in a cave.

A grain sample was found in a cave. The amount of carbon-14 in the sample was 1/16 the amount found in a fresh sample of grain. How old was the grain in the cave? The half-life of carbon-14 is 5600 years.

Reaction rate constant and kinetics

The reaction CH3CH2N02 + 0H^- -----> CH3CHN02^- + H20 has the rate r=k[CH3CH2N02][0H^-] it takes 0.5 min for one % of CH3CH2N02 to react at 25 degrees C, in the case of a solution 0.002 M in CH3CH2N02 and 0.3 M in Na0H. a) Calculate k. b) Calculate also how long it would take f

Rates of Effusion

Which species, ^235(UF6) or ^238(UF6), would you expect to effuse faster through a porous membrane? How much faster, i.e. what are the relative rates of effusion?

Ratio of rates from Arhenius equation

. Question : Two reactions have the same Arhenius frequency factor, while their energies of activation differ by 5020 Jmol-1. Calculate the ratio of their rate constants at 27degree Celsius

Rate Constant for Temperatures

As you are aware, temperature affects the rate of reactions. You have the following reaction: 2A + B = C (equilibrium is = sign). For this reaction at 25 degrees Celsius, the forward rate constant, kf, is larger than the reverse rate constant, kf (i.e., kf = 10 to the 3rd x kr). Would there be a temperature at which this re

Half-life and Periodic Trends

Because the time it takes for a reaction to actually reach equilibrium is infinite, scientists have used the estimate that after ten half-lives (or ten half-times) the reaction is completed (i.e., the reaction has reached equilibrium). Chlorine gas and solid sodium metal react to produce sodium chloride. If you place one mole

General Chemistry

Kc for the reaction below at 25°C is 4.8 x 10-6. Calculate the equilibrium concentration (mol/L) of Cl2(g) if the initial concentration of ICl(g) is 1.33 mol/L. There is no I2 or Cl2 initially present. 2ICl(g) <-> I2(g) + Cl2(g) a. 6.4 x 10-6

General Chemistry problems

1. The relationship between the rate constants for the forward and reverse reactions and the equilibrium constant for a process is K = ____________. a. kf/kr b. kfkr c. kf+kr d. kf-kr e. 1/(kfkr) 2. Consider the following equilibrium. 2 SO2(g) + O2(g) 2 SO3(g) From which of the following starting conditions would

General Chemistry

A sample of radioactive curium was found to decay in a manner that follows a first order create reaction. After 1.00 year the activity of the sample had declined from 3012 disintegration per second (create as a concentration) to 2921 disintegration per second (treat as a concentration). What is the half-life of the decay process

Kinetics: various calculations

1) Calculate the mole fraction of methanol (CH OH) in a mixture of equal masses of methanol and water. 2) Calculate the molar concentration of chloride ions in a solution prepared by dissolving 454g of CaCl in water and diluting to 500mL. 3) At 25 degrees Celcius calcium chloride has a solubi

Solving for Activation Energy

Question: Activation Energy. Use the data below to answer the following questions about a chemical reaction. A. What is the activation energy for the chemical reaction? B. What is the value of the rate constant at 430.0 K? Temperature (Degrees°C) k (1/s) 189.7 2.52 x 10-5 198.9

Catalyst Decomposition Mechanism

Acetaldehyde can undergo catalytic decomposition according to the mechanism below: CH3CHO + I2 = CH3I + HI + CO (RDS) CH3I + HI = CH4 + I2 Use the mechanism to determine: a. the overall chemical equation b the catalyst c the intermediates d. the rate law

Gas Laws Problems

1. How do you find the ratio of rates (in grahams law) when you only are given the molar masses? 2. How do you find the t2 when you are given P1, t1, V1, and P2, and V2?

Kinetics, 1/2 life question

Can you please explain how we are using the half life equation in this question? to get mass in grams after 13 days. The question is as follows: Gallium-67 (t 1/2 = 78.25 hours) is used to diagnose certain tumors. If you ingest 0.055 mg of 67 GA what mass will remain in 13 days. I started out using the integrated rate

First Order Reaction

The following first order reaction is conducted in an inert liquid at 45 celsius: N2O5 N2O4 + 1/2 O2 THE RATE CONSTANT IS K=6.2*10 XY TO -4 SXY -1 AN 80.0g SAMPLE OF N2O5 IS DISSOLVED IN THE INERT LIQUID AND ALLOWED TO DECOMPOSE AT 45 CELSIUS. 1- HOW LONG WILL IT TAKE FOR THE QUANTITY OF N2O5 TO BE REDUCED TO 2.

Law of effusion and molar mass

Please explain the below problems, thanks: A polymer chemist dissolves 6.053g of poly(vinyl alcohol) in enough water to make 100.0mL of solution. At 25 C, the osmotic pressure of this solution [w/respect to pure water] is 0.272atm. What's the molar mass of the polymer sample? ans: 5.44x10^3 ------------------- A b

Specific Rate Constant

Evaluate the specific rate constant for the reaction at the temperature for which the data were obtained. The rate-law expression is rate=k[A][B]squared. A + B>>>>>> C Experiment Initial [A] Initial [B] Initial Rate of Formation of C 1 0.10 M 0.10 M

Apply steady-state approximation

Consider the following mechanism for the reaction of nitric oxide with hydrogen: 1) 2NO ----> N2O2 <---- 2) N2O2 + H2 -----> N2 + H2O2 3) H2O2 + H2 ----> 2 H2O a) apply the steady state approximation to one or more of the intermediates and thence derive the rate law for the overall reaction. B) unde

Reaction rate and tempersture

For the reaction: C2H4(g) + H2(g)----> C2H6(g) the activation energy is 181kJ/mol. The rate constant at 1000 degrees celsius is 1.6 x 10^3 L/mol/s. A.) at what temperature is the rate constant half its value at 1000 degrees Celsius? B.) What is the rate constant at 725 degrees Celsius?

Rate expression for Reaction

The equation for the reaction between iodide and bromate in acidic solution is 6I-(aq) + BrO3-(aq) + 6H+(aq) ---> 3I2(aq) + Br-(aq) + 3H2O The rate of the reaction is followed by measuring the appearance of I2. The following data are obtained. [I-] [BrO3-] [H+] Initial Rate (mo

Zero order reaction

For the zero order decomposistion of HI on a gold surface it takes 1.0 seconds for the concentration of HI to drop from 0.335M to 0.285M. HI(g)---> 1/2H2(g)+1/2I2 I need to know what is the rate constant for the reaction, how long will it take for the concentration of a 0.650M solution to drop to 0.0100M, and what is the hal

Beta decay

A 25.0 mg sample of 148/58 CE (t 1/2=48s) undergoes beta decay. After 4.50 min, how much of the original sample is left, what is the product formed and how much of the product is formed?

Oxidation Experiment

If you had the follwing two oxides: Hematite (Fe2O3), magnetite(Fe3O4) How would you conduct a simple experiment to show the different oxides of Iron? Thank you so much! PS. In my lab, we just did an experiment with AL and two different unknown Copper oxides: Cu2O and CuO. We were given one of the unknown copper oxid

Recognizing the Order of a Reaction

In the reaction 2 A + 2 B ----> C + 3 D the rate of disappearance of A is -2.2 X 10^-4 M s -1. What is the rate of formation of C? The answer states A = to 1.1 x 10^-4 M/s. What happened to the "-1" in this situation? Can these measures for rates, Ms^-1 and s-1, be used to help identify first second and third order?

Chemical Kinetics Problems

Please explain what the s-1 means in the rate constant calculation. Can you please describe in detail why this is being added on as a unit and what it is used for.

Rates of Reaction Problem

A particular reaction was found to depend on the concentration of the hydroxyl ion [OH-]. The initial rates varied as a function of initial pOH as follows: pOH 2.699 2.398 2.097 initial rate 1.600e-2 6.400e-2 2.560e-1 (M/s) Predict the initial reaction rate when pOH is 2.155.

Reactions

For the reaction BrO3- + 5 Br- + 6 H+ ---> 3 Br2 + 3 H2O at a particular time, -/[BrO3-]// t = 1.5 10-2 M/s. What is -/[Br-]//t at the same instant? Question 2 Question: The reaction A + 2 B ---> products has been found to have the rate law, rate = k [A]

Arrhenius Equation

The Arrhenius equation relates reaction rates to temperature via the activation energy. Calculate the ratio of the rates at -30 degrees C (a typical stratospheric temperature) for two biomolecular reactions having the same Arrhenius A factor and initial concentrations , one of which is endothermic and has an activation energy of