Unit 2. Reaction Thermochemistry

This website provides learning and teaching tools for a first course on kinetics and reaction engineering. The course is divided into four parts (I through IV). Here, in Part I of the course, a brief review of some basic concepts related to chemical reactions is presented. Students taking their first kinetics and reaction engineering course should already be familiar with most of the material that is presented in this part of the course. The concepts that are reviewed here will be utilized repeatedly throughout the remainder of the course, and therefore it is critically important to master them before proceeding to the main body of the course, Parts II, III and IV.

Chemical reactions are processes wherein chemical bonds are broken and/or formed. Breaking a chemical bond requires the input of energy and forming a chemical bond releases energy. Unit 2 shows how thermodynamics data can be used to calculate the energy changes associated with chemical reactions and how those energy changes vary with temperature. It also shows how the resulting heat of a reaction can be used to calculate the temperature change that occurs when reactions take place adiabatically (that is, without the input or removal of any energy). The information presented in this unit is essential in chemical reaction equilibrium analysis and in reaction engineering.

Learning Resources

• Archive (.zip) - Contains all learning resources listed below for this unit, except for the simulators
• Documents to Read:
  • Unit 02 Informational Reading (.pdf)
  • Example 2.1 (.pdf)
  • Example 2.2 (.pdf)
  • Example 2.3 (.pdf)
  • Example 2.4 (.pdf)
• Videos to Watch (please right-click and save, then play back locally on your computer):
  • Unit 02 Informational Video (.mov)
  • Example 2.1 Video (.mov)
  • Example 2.2 Video (.mov)
  • Example 2.3 Video (.mov)
  • Example 2.4 Video (.mov)
• Reference Files:
  • Unit 2 Definitions, Nomenclature and Equations (.pdf)
  • How To Calculate a Heat of Reaction (.pdf)
• Other Files:
  • Example_2_1.m - MATLAB file used in the solution of Example 2.1
  • Example_2_2.m - MATLAB file used in the solution of Example 2.2
  • Reaction Thermodynamics Simulators
    • Methyl Chloride Synthesis (zipped .jar file)
    • Reverse Water-Gas Shift (zipped .jar file)
    • Methanol Synthesis (zipped .jar file)
     
    Please note that these simulators are intended for educational purposes only. They should not be used for any other purpose, and if they are, the author does not bear any responsibility or liability for the consequences.
     
    The “zipped .jar file,” when unzipped, will produce a folder that contains a .jar file and a folder named "lib". Not surprisingly the latter folder contains additional libraries and files that the simulator uses. To run the simulator, launch the .jar file either from the command line using java -jar [name of .jar file], or by double clicking it if your operating system supports it. The simulators require JAVA 1.6 or later in order to run. There is a User's Guide under the Help menu that describes how to use the simulators.
     
    

Teaching Resources

• Archive (.zip) - Contains all teaching resources listed below for this unit, except for the simulators
• Sample Class
  • Online Pre-class Quiz (.pdf file)
  • Redacted slides to make available to students before class
    • Keynote 09
    • PowerPoint
  • Learning Activity Files to make available to students before class
    • Activity 1 Handout (.pdf)
  • Class Lesson Plan (.pdf)
  • Complete slides to make available to students after class
    • Keynote 09
    • PowerPoint
• Alternative Questions (.pdf) that could be used in a pre-class quiz
• Simulator Source files
  • Methyl Chloride Synthesis (zipped Netbeans project folder)
  • Reverse Water-Gas Shift (zipped Netbeans project folder)
  • Methanol Synthesis (zipped Netbeans project folder)
   
  Please note that these simulators are intended for educational purposes only. They should not be used for any other purpose, and if they are, the author does not bear any responsibility or liability for the consequences.
   
  The “Netbeans Project folders” contain the Netbeans java project used to create them. Providing them in this way will allow instructors or students familiar with java and the Netbeans development environment to modify them. They were developed using version 6.7 of Netbeans. They use the Swing Application Framework, which is not supported in version 7.1 or higher of the Netbeans IDE. They are no longer in development, and I am not available to consult on any issues encountered when using them.

Practice Problems

1. The water-gas shift reaction, equation (1a), is used in a process for the removal of CO from hydrogen. Hydrogen is commonly manufactured by reacting steam with a hydrocarbon such as methane, and as a result, the product gas typically contains both CO and CO₂. CO₂ can be removed with relative ease by scrubbing the gas with an amine solution. Thus, before scrubbing, the water-gas shift reaction is used to convert as much of the CO as possible into CO₂. Generate an expression for the standard heat of the water-gas shift reaction as a function of the temperature. (You can find the necessary thermodynamic data in "The Properties of Gases and Liquids," 3^rd ed. by Reid, Prausnitz and Sherwood. McGraw-Hill, New York, 1977, among other sources.)

(Problem Statement as .pdf file)

2. Suppose that the feed to an adiabatic water-gas shift reactor consists of 40% steam, 10% CO, 5% CO₂, 35% H₂ and 10% N₂ at a temperature of 340 °C and a pressure of 25 atm. (See Practice Problem 1, above, for information about the water-gas shift reaction.) Generate an expression for the outlet temperature as a function of the fractional conversion of CO. (You can find the necessary thermodynamic data in "The Properties of Gases and Liquids," 3^rd ed. by Reid, Prausnitz and Sherwood. McGraw-Hill, New York, 1977, among other sources.) (Problem Statement as .pdf file)

3. The oxidation of ethanol to produce acetic acid is given in equation (3a). Standard heats of formation (gas phase) at 298K and average gas phase heat capacities for temperatures between 298 and 400 K for ethanol, acetic acid, oxygen and water vapor are given in the table below. Use those data to generate an expression for the standard heat of reaction (3a) as a function of temperature and calculate the standard heat of reaction at 300, 350 and 400 K. Comment upon the result.

(Problem Statement as .pdf file)