CHE 116 Chapter Notes - Chapter 14: Enzyme, Reaction Mechanism, The Exponents

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cyanherring316

29 Jan 2018

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The greater the frequency of collisions, the higher the reaction rate. Collisions only become reactions if it occurs with enough energy to break bonds and with appropriate orientation for new bonds to form in the proper locations. Speed: the change that occurs in a given time interval. The quantity that is changing divided by a time interval. Reaction rate: the change in the concentration of reactants or products per unit of time (m/s) Rates are always expressed as positive quantities. Instantaneous rate: the rate at a particular instant during the reaction; determined from the slope of the curve at a particular point in time. If stoichiometric coefficients are the same the rates are the same. Changing the initial concentration of either reactant changes initial reaction rate. Reaction orders: the exponents in the rate law. Overall reaction order: the sum of the orders with respect to each reactant represented in the rate law.

Related Questions

1a. Collision theory helps us to explain the factors affecting the rate of reactions between molecules. Select all of the following that should increase the rate of a reaction.

Increasing the concentration of the reactants.

Using complex molecules that have a limited number of sites where a collision will be successful.

Adding a catalyst that decreases the size of E_a.

Increasing the volume of the solution by dilution.

Decreasing the temperature of the reaction.

1b. Select all of the following that would act to make the value of k become smaller.

The temperature of the reaction is decreased.

The reactant has many sites for a successful collision to occur.

A catalyst is used which acts to lower the activation energy for the reaction.

The mobility of the molecules is decreased so that there are fewer collisions.

The reaction is heated.

The concentration of the reactant is increased.

For a reaction aA rightarrow Products, [A]_o = 13 M, and the first two half-lives are 35 and 70 minutes, respectively, a) Write the rate law for this reaction. b) Calculate k. c) Calculate [A] at t = 335 minutes The Model of Chemical Kinetics represents the reaction rate constant as: k = (2p) times exp(-Ea/RT). What does each variable in the equation mean- that is, in regard to their contribution towards the reaction rate constant? In other words, what does each variable actually mean/refer to? Chemists commonly use a rule of thumb that an increase of 10 K in temperature doubles the rate of a reaction. What must the activation energy be for this statement to be true for a temperature increase from 63 degree C to 73 degree C? ln(k_2/k_1) = E_a/R(1/T_1 - 1/T_2) (i) What is a catalyst? (ii) What are the two types of catalysts? Explain specifically why they are different? (iii) What is one example of each type of catalyst? (i) What does it mean when a reaction is in chemical equilibrium? Specifically, within the context of reactants? products, and the forward and reverse reaction rates, what does chemical equilibrium mean? (ii) What is Le Chateleir's Principle? Within the context of reactant/product concentration, temperature, and pressure, how does Le Chatelier's Principle predict a reaction will respond to variations in reactant, product concentration, temperature, and pressure. (i) For the given reactions: N_2(g) + 3H_2(g) harr 2NH_3(g), H_2O(g) + CO(g) harr H_2(g) + CO_2(g), HCN(aq) harr H^+(aq) + CN^-(aq), 2KClO3(s) harr 2KCl(s) + 3O_2(g) and 2H_2 O(l) harr 2H_2(g) + O_2(g). Write the equation that governs each of their equilibrium rate constant K (ii) If N_2(g) + 3H_2(g) harr 2NH_3(g)'s (at 25 degree C) has K = 25, what would K be (at 25 degree C) for 2NH_3(g) harr N_2(g) + 3H_2(g)? (iii) What would K be if [5 times (N_2(g)+3H_2(g) harr 2NH_3(g)]? (i) For N_2(g) + 3H_2(g) harr 2NH_3(g): P_NH3: 1.9 times 10^-1 atm, P_N2 = 8.9 times 10^-2 atm, P_H2 = 1.9 times 10^-2 atm, what is K_p? (ii) Using K_p, calculated in the previous step, what is K at 45 degree C, where K_p = K(RT)^Delta n? (R = 0.08206 L atm/mol K). What is the difference between homogeneous and heterogeneous? (ii) If K is larger than 1, does the equilibrium life farther to the right (favoring the production of products) or to the left (favoring reactant formation)? (iii) If K is less than 1, does the equilibrium life farther to the right (favoring the production of products) or to the left (favoring the production of reactants)?

CHE 116 Chapter Notes - Chapter 14: Enzyme, Reaction Mechanism, The Exponents

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