6.01 – Reaction Rates & Rate Factors


It is time to break down the various aspects of chemical reactions and time.  In this mission, we will focus upon the methods of measuring reaction rates and the factors that can influence the rate of a reaction.

 

 

Lesson Objectives

  • List the factors that affect the rate of chemical reactions. (14.1)
  • Determine the rate of a reaction given time and concentration. (14.2)
  • Relate the rate of formation of products and the rate of disappearance of reactants given the balanced chemical equation for the reaction. (14.2)

To become familiar with the topics presented in this mission, view the slides below and take note of the key ideas.  These are from sections 14.1-14.2 of your text.

Now work through the practice problems, and post your work to OneNote.

Figure 14.3   -   Figure 14.4

Work out these mastery problems and check your answers in OneNote.  Post your work when finished, including any corrections.  These questions are from the text.

14.18  The rate of disappearance of HCl was measured for the following reaction:

CH3OH(aq) + HCl(aq) → CH3Cl(aq) + H2O(l)

The following data were collected:

Time (min) [HCl] (M)
0.0 1.85
54.0 1.58
107.0 1.36
215.0 1.02
430.0 0.580
  1. Calculate the average rate of reaction, inM/s, for the time interval between each measurement.
  2. Calculate the average rate of reaction for the entire time for the data fromt= 0.0 min to t = 430.0 min.
  3. Which is greater, the average rate betweent = 54.0 and t = 215.0 min, or between t = 107.0 and t = 430.0 min?
  4. Graph [HCl] versus time and determine the instantaneous rates inM/min andM/s at t = 75.0 min and t = 250 min.

 

 14.11  Draw a possible transition state for the bimolecular reaction depicted here. (The blue spheres are nitrogen atoms, and the red ones are oxygen atoms.) Use dashed lines to represent the bonds that are in the process of being broken or made in the transition state.

 

 

14.93  Cyclopentadiene (C5H6) reacts with itself to form dicyclopentadiene (C10H12) A 0.0400 M solution of C5H6 was monitored as a function of time as the reaction 2 C5H6 → C10H12 proceeded. The following data were collected:

 

Time (s) [C5H6] (M)
 0.0 0.0400
 50.0 0.0300
100.0 0.0240
150.0 0.0200
200.0 0.0174

Plot [C5H6] versus time, ln [C5H6] versus time, and 1/[C5H6] versus time.

 

  1. What is the order of the reaction?
  2. What is the value of the rate constant?

 

 

 

 

 

Now we know about how quickly reactions proceed.  Don't you feel better?