UTPA STEM/CBI Courses/Magic Blue Bottle

Course Title: Physical Chemistry

Lecture Topic: Magic Blue Bottle

Instructor: Aijie Han

Institution: University of Texas-Pan American

Backwards Design

Course Objectives

Primary Objectives- By the next class period students will be able to:
- understand the mechanism of the reaction
- identify reversible or irreversible reaction
- set up a crude manometer

Sub Objectives- The objectives will require that students be able to:
- understand the reason of the color change
- establish the ability to think ways to verify their guess and ideas

Difficulties- Students may have difficulty:
- Since the color changes from blue to colorless, and colorless or blue, the students will assume that it is a reversible process.
- The students will have difficulty to find out what is the reason of the color change.

Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
- The cut apple becomes brown quickly because of the oxidation by the oxygen in the air.
- The ion is rusted with color change.

Model of Knowledge

Concept Map
- Understanding the oxidation-reduction reaction
- Identify the oxidizing and reducing agents
- Understanding the reversible and irreversible reactions

Content Priorities
- Enduring Understanding
  - oxidation-reduction reaction
  - oxidizing and reducing agents
  - reversible and irreversible reactions
- Important to Do and Know
  - The indicator, methylene blue shows blue color when it is oxidized, while it changes to colorless when it is reduced.
  - The oxygen is the oxidizing agent for the reaction.
  - The unknown solid (glucose) is the reducing agent for the reaction.
- Worth Being Familiar with
  - the working principle of a manometer
  - The rate of the coloration step is faster than the rate of the decoloration step
  - The more shakes of the solution, the deeper blue color of the solution.

Assessment of Learning

Formative Assessment
- In Class (groups)
  - prepare the solution
  - group questions for possibles sources of the coloration suggested
- Homework (individual)
  - do experiments to verify or disprove the suggested possibilities about the coloration
  - set up a simple manometer to test the pressure change when the color change happens
Summative Assessment
- report
- presentation

Legacy Cycle

OBJECTIVE

By the next class period, students will be able to:

Understand the oxidation-reduction reaction
Understand the reversible and irreversible reactions
Identify the oxidizing and reducing agents

The objectives will require that students be able to:

set up a simple manometer
establish the ability to find ways to verify their ideas
predict the mechanism behind the phenomenon

THE CHALLENGE

In our ordinary life, the fresh cut apples become brown very quick. What happens?

GENERATE IDEAS

The apple is bad. The apple is oxidized. The apple is oxidized by the air. The apple is oxidized by the oxygen in the air.

MULTIPLE PERSPECTIVES

The professor will introduce the knowledge of methylene blue, the oxidation-reduction reaction, the reversible and irreversible reactions, and the reaction mechanism. In order to give the students a better understanding of the topic, the students will use online information and handout from the instructor.

RESEARCH & REVISE

Students will be provided with the chemicals for the experiment. They will be divided into groups and be asked to prepare the experiment. During the experiment, the students will follow the procedures provided by the instructor and answer some questions to direct the results.

For instance, in order to verify the oxidization agent for the reaction is oxygen, the students will replace the air by nitrogen or natural gas. For instance, in order to observe the pressure change when the oxygen is consumed during the reaction, the student will set up a simple manometer.

TEST YOUR METTLE

Students will receive feedback on their experiment and will be asked with some questions to see whether they undnerstand the process.

GO PUBLIC

Students will submit a report and present their work.

Pre-Lesson Quiz

1) Which of the following is oxidized in the following reaction? Fe + Ag2O -> FeO + 2Ag A. Ag B. Ag2O C. Fe D. FeO E. 2Ag

2) Which of the following is reduced in the following reaction? Cu(NO3)2 + Zn -> Zn(NO3)2 + Cu A. Cu(NO3)2 B. N C. O D. Zn E. NO3

3) Which one of these equations describes a redox reaction? A. 2Al(s) + 3H2SO4(aq) -> Al2(SO4)3(aq) + 3H2(g) B. 2KBr(aq) + Pb(NO3)2(aq) -> 2KNO3(aq) + PbBr2(s) C. CaBr2(aq) + H2SO4(aq) -> CaSO4(s) + 2HBr(g) D. H+(aq) + OH- (aq) -> H2O(l) E. CO32- (aq) + HSO4-(aq) -> HCO3- (aq) + SO42- (aq)

4) Which of these equations does not represent an oxidation-reduction reaction? A. 3Al + 6HCl -> 3H2 + AlCl3 B. 2H2O -> 2H2 + O2 C. 2NaCl + Pb(NO3)2 -> PbCl2 + 3NaNO3 D. 2NaI + Br2 -> 2NaBr + I2 E. Cu(NO3)2 + Zn -> Zn(NO3)2 + Cu

5) What element is oxidized in the chemical reaction H2SO4 + Cd(OH)2 -> 2H2O + CdSO4? A. H B. S C. O D. Cd E. This is not a redox reaction.

Test Your Mettle Quiz

1) What element is reduced in the chemical reaction Cu + 2H2SO4 -> CuSO4 + SO2 + 2H2O? A. Cu B. H C. S D. O E. H2O

2) Identify the reducing agent in the chemical reaction 5Fe2+(aq) + MnO4-(aq) + 8H+(aq) -> 5Fe3+(aq) + Mn2+(aq) + 4H2O(l). A. Fe2+ B. MnO4- C. H+ D. Mn2+ E. Fe3+

3)Identify the reducing agent in the chemical reaction Cd + NiO2 + 2H2O -> Cd(OH)2 + Ni(OH)2. A. Cd B. NiO2 C. H2O D. Cd(OH)2 E. Ni(OH)2

4) In the chemical reaction 5H2O2 + 2MnO4- + 6H+ -> 2Mn2+ + 8H2O + 5O2, the oxidizing agent is: A. H2O2 B. MnO4- C. H+ D. Mn2+ E. O2

5) Identify the oxidizing agent in the chemical reaction 2MnO4- + 5H2SO3 -> 2Mn2+ + 5SO42- + 4H+ + 3H2O. A. MnO4- B. H2SO3 C. Mn2+ D. SO42- E. H+