Chemistry HW CHEMICAL REACTIONS

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organix

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Chemistry HW CHEMICAL REACTIONS

« on: March 21, 2011, 10:57:25 am » I answered a couple of them,but I am having trouble with these. . . 3. A combination reaction gave the following data. What is the rate law for this reaction?J  K → ÎœInitial Concentration Initial Rate(mol/L) (mol/Lps)[J] [K]0.30 0.50 0.0800.60 0.50 0.1600.60 0.25 0.0804. Iodide ion catalyzes the decomposition of hydrogen peroxide. The reaction is first-order in H2O2. What is the value of the rate constant, k, if the initial rate is 0.00842 mol/(Lps)?The initial concentration of H2O2 is 0.500 mol/L.2H2O2 → 2H2O  O25. A proposed reaction mechanism has two intermediates. How many elementaryreactions are in this mechanism?6. The reaction A  B → C is first-order in A and B, second-order overall.Complete the following table:Initial Concentration Initial Rate(mol/L) (mol/Lps)[A] [ B]0.50 0.50 0.0200.50 ? 0.0400.25 1.00 ?7. The condensation of acetic acid (C2H4O2) with methanol (CH4O) to form methylacetate (C3H6O2) and water is catalyzed by HCl.C2H4O2  CH4O 1 HCl C3H8O31 HCl C3H6O2  H2Oa. How many elementary reactions are there in this condensation?b. Write the formula for the reaction intermediate(s).c. Write the rate law for this condensation. « Last Edit: March 25, 2011, 06:55:30 pm by Borek » Logged

DevaDevil

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Re: Chemistry HW CHEMICAL REACTIONS

« Reply #1 on: March 21, 2011, 11:47:12 am » 3. rate equation: rate = constant * [J]n * [K]m, look at your table and try to see the dependence of the rate on the concentrations. What do the coefficients n and m have to be?4. what is the rate equation of a first-order reaction?5. how far do you get, try first please6. can you write the rate equation, based on the info of 1st order in A and B?7. can you try some reactions that might happen? HCl is a strong acid, where would it react first? Logged

organix

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Re: Chemistry HW CHEMICAL REACTIONS

« Reply #2 on: March 25, 2011, 11:03:41 am » Quote from: DevaDevil on March 21, 2011, 11:47:12 am

3. rate equation: rate = constant * [J]n * [K]m, look at your table and try to see the dependence of the rate on the concentrations. What do the coefficients n and m have to be?4. what is the rate equation of a first-order reaction?5. how far do you get, try first please6. can you write the rate equation, based on the info of 1st order in A and B?7. can you try some reactions that might happen? HCl is a strong acid, where would it react first?

3. A combination reaction gave the following data. What is the rate law for this reaction?J K → ÎœInitial Concentration Initial Rate(mol/L) (mol/Lps)[J] [K]0.30 0.50 0.0800.60 0.50 0.1600.60 0.25 0.080rate = constant * [J]n * [K]m 4. Iodide ion catalyzes the decomposition of hydrogen peroxide. The reaction is first-order in H2O2. What is the value of the rate constant, k, if the initial rate is 0.00842 mol/(Lps)?The initial concentration of H2O2 is 0.500 mol/L.2H2O2 → 2H2O O2RATE=K[A]a[ B]b5. A proposed reaction mechanism has two intermediates. How many elementaryreactions are in this mechanism? There are four reactions in a mechanism.6. The reaction A B → C is first-order in A and B, second-order overall.Complete the following table:Initial Concentration Initial Rate(mol/L) (mol/Lps)[A] [ B]0.50 0.50 0.0200.50 0.0400.25 1.0 Do not understand this too well.7. The condensation of acetic acid (C2H4O2) with methanol (CH4O) to form methyl acetate (C3H6O2) and water is catalyzed by HCl.C2H4O2 CH4O 1 HCl C3H8O31 HCl C3H6O2 H2Oa. How many elementary reactions are there in this condensation?One = C3H8O31b. Write the formula for the reaction intermediate(s).N2O --->n2+oN2o+o--->n2+o22N20--->2N2+o2c. Write the rate law for this condensation.rate= -_TA__=Concentration A-ConcentrationB TT t2-t1 « Last Edit: March 25, 2011, 06:56:07 pm by Borek » Logged

DevaDevil

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Re: Chemistry HW CHEMICAL REACTIONS

« Reply #3 on: March 28, 2011, 11:52:35 am » in question 3, you have to deduce the coefficients from the table. How does the reaction rate depend on the concentration of one component, when the other is constant and what does this mean for the coefficients m and n?4. you wrote a general reaction rate in terms of the products, but the question asks you to write it in terms of the reactant... (H2O2). Please attempt, do not just copy a general reaction rate law.5. Are there? Can you write the separate steps down? (in terms of e.g. A -> B (step 1) and so on)6. Okay, let's start with the rate equation: reaction rate = k * [A]n * [B ]m, what are the coefficients based on what it says in the question?Then, if the reaction rate doubles, but the concentration of A stays the same, what does this mean for the concentration of B (fill the values in the rate equation)The last ? has concentration of A halve, and the concentration of B double, what does this mean for the rate?7. there is indeed 1 stable intermediate, but what does this mean for elementary steps?b) what is meant is that you write down what the intermediate molecule looks like. I do not know why you write the decomposition of N2O here.c) write the reaction rate in terms of the products, not just A and B (do not integrate yet, you will have a differential equation) Logged

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