🏷️ LIMITED TIME OFFER: GET 20% OFF GRADE+ YEARLY SUBSCRIPTION →

HomeClass Notes1,200,000US530,000

CHEM 1214 Lecture Notes - Lecture 1: Enthalpy, Collision Theory, Activated Complex

15 views2 pages

15 Sep 2016

School

Northeastern University

Department

Chemistry & Chemical Biology

Course

Professor

Lykourinou Vasiliki

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Reaction rate: reaction rate: change in concentration over change in time, a b. Rate of disappearance of a: - [a]/ t: 2n2o5 4no2 + o2. (- [n2o5]/ t) = ( [no2]/ t) = 1/1( [o2]/ t: we cannot calculate a single number that expresses the rate for the entire reaction. Instead, we can calculate the average rate over a given interval of time (final-initial), or the instantaneous rate at a given instant in time (slope of tangent at specific time). Collision theory: reactions occur when molecules collide with sufficient kinetic energy to break chemical bonds. The reaction then proceeds and the activated complex splits into the products. Chemical kinetics: study of rate of change of concentrations of substances involved in chemical reactions. Reaction rate: how rapidly a reaction occurs; related to rates of change in concentration of reactants and products over time.

Related textbook solutions

Chemistry: Structure and Properties

ISBN: 9780134293936

Basic Chemistry

ISBN: 9780134138046

Principles of Chemistry Molecular Approach

ISBN: 9780134112831

Chemistry: Structure and Properties

ISBN: 9780134293936

Principles of Chemistry Molecular Approach

3rd Edition, 2014

ISBN: 9780321971944

Chemistry: A Molecular Approach

ISBN: 9780321809247

Chemistry: A Molecular Approach

ISBN: 9780134874371

Principles of Chemistry: A Molecular Approach

ISBN: 9780134895741

Chemistry: The Central Science

14th Edition, 2017

ISBN: 9780134414232

Related Documents

[CHEM 1214] - Final Exam Guide - Everything you need to know! (54 pages long)

CHEM 1214 Study Guide - Midterm Guide: Joule, Sodium Chloride, Exothermic Process

limesea-lion526

CHEM 1214 Lecture Notes - Lecture 2: Limiting Reagent, Arrhenius Equation, Radioactive Decay

Related Questions

Just answer

Did the reaction actually stop when the blue-black color appeared? Explain briefly

EXPERIMENT 16 A Kinetic Study of an Iodine Clock Reaction OBJECTIVES: To measure experimental reaction rates under different conditions. To use the method of initial rates to determine the order of reaction. To determine the rate constant of a reaction at different temperatures. To determine the activation energy of a reaction using graphical techniques. rate law. To make deductions regarding a reaction mechanism, based on the INTRODUCTION: According to chemical kinetics, it is possible to write down a Rate Law' for any chemical equation: Rate k[A]m [B] This rate law can be used to calculate the rate at which that particular reaction will proceed when a given concentration' of [A] and [B] are present in the system. However, to do this we must know the value of (it is temperature dependent). k rate constant m order with respect to concentration of A. n order with respect to concentration of B. It is important to realize that the values of k, m and n cannot be determined by looking at the chemical equation. They must be deduced experimentally someone must actually run and time the reaction under varying conditions. In this lab, we will studythe Rate Law forthe following reaction between the persulfate ion,s2os and the iodide ion. General Rate Lane. Rate -k ]m [s20g2-1n This reaction is called a clock reaction b of the thiosulfatestarch indicator system we use to time the reaction. Every you run this reaction, your flask will contain an indicator system consisting of time 5.0 x 105 moles of thiosulfate' ions, S2032, and a little starch. When the two reactants, Ose are first mixed start the reaction, every molecule of I2 that is produced reacts immediately with any nt according to the following chemical equation. S2032-preset 21- S40 12 2 S203 This removes the first 2,5 x 10 s moles I2 (look at stoichiometry of reactions above) from the system but then the thiosulfate is gone. This point is marked by the almost instantaneous appearance of an intense blue-black Also called Rate Equation and Rate Law Expression square brackets around anything, [X], means moles per liter of Xor molarin of x. You pipet 100 ml of 0.0050 M Naasio, into each flask.

33-To stabilize the transition state complex, which of the following must be lowered? A) Initial energy state B) Activation energy C) Net energy change D) The Vmax B) Final energy state 34- Which of the following statements about allosteric enzymes is CORRECT? A The binding of substrate to any active site affects the other active sites B The plot of initial velocity vs. substrate concentration is a straight line C The Keq of the reaction is increased when allosteric activator is bound D The enzymes contains only one polypeptide chain E Allosteric activators bind to all active sites equally 35. Which statement about the two different models proposed to explain enzyme specificity is CORRECT. a. The substrate changes shape when enzyme binds in the Lock and Key Model. b. The enzyme undergoes a covalent modification when bound to substrate in the Lock and Key Model. c. The active site of the enzyme alternates in conformation between opened and closed in the Induced Fit Model. d. The enzyme changes conformation after binding the substrate in the Induced Fit Model. eÂ·The product structure is altered after it has bound to the enzyme in the Induced Fit Model. 36. An enzymatic reaction proceeds with maximal velocity (Vmax) when A. the substrate concentration is equal to that of a competitive inhibitor. B. allosteric effectors are present. C. the enzyme substrate complex is maximal. D. the substrate concentration exceeds that of a noncompetitive inhibitor. E. all of the substrate is bound to the enzyme. 37. Which of the statements below are incorrect? A With all other factors that modify the rate of the enzyme catalyzed reaction remaining constant as we raise the temperature of an enzyme catalyzed reaction there is an initial increase of velocity with temperature. B. The rate of reaction increases with temperature because there is an increasing number of molecules with sufficient energy to pass over the energy barrier which we call the energy of activation C. Reaction rate increases with temperature until a maximum is reached, when the rate of the reaction will suddenly suddenly fall to zero because the enzyme will be denatured and therefore inactive. D. The reaction rate initially increases as temperature rises owing to increased kinetic energy of the reacting molecules E. Enzymes in crease reaction rates due to their ability to lower the energy barriers for reactions F. None of the above 38- Which of the following is true for the induced fit theory of enzyme action? A. The conformation of the substrate changes before binding to the enzyme. B. The active site changes shape during binding of the substrate C. The substrate fits into a preformed active site through a lock-and-key mechanism. D. Enzymes alternate between conformations where the active site is either open or closed. E. The substrate causes a cleft to form in the enzyme where it subsequently binds