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Greening the Clock Reaction: Rates of Reaction Lab

Greening the Clock Reaction: Rates of Reaction Lab
Contributors
Mollie Enright
Beyond Benign, Inc.
Annette Sebuyira
Retired K-12 Educator | Beyond Benign, Inc.
Janie Butler
Education and Workforce Development Specalist | Science Done Sustainably
Beyond Benign
Beyond Benign, Inc.
Learning Objets
Summary
The amount of each reactant present and the temperature of the reaction vessel typically influence the rate at which a chemical reaction proceeds. And, typically, this relationship between the reaction rate and reagent concentration takes a simple form known as the rate law: rate = k[A]x[B]y

Clock reactions can be performed with a variety of reagents, including bisulfites, formaldehyde, mercuric ions, and thiosulfates. The traditional clock reaction involves the use of mercuric ions. While mercury compounds are typically not used in today’s classrooms, this lab provides an excellent example for highlighting how experiments have evolved and the importance of green chemistry.


Keywords
Reaction Rate
Chemical Reactions
Iodine Clock Reaction
Kinetics

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Moderation state
Published
Object Type
Laboratory experiment
Audience
High School (Secondary School)
Published on
Green Chemistry Principles
Safer Solvents and Auxiliaries
NGSS Standards, if applicable
HS-PS1-5. Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.

HS-PS3-4. Plan and conduct an investigation to provide evidence that the transfer of thermal energy when two components of different temperatures are combined within a closed system results in a more uniform energy distribution among the components in the system (second law of thermodynamics).
Learning Goals/Student Objectives
Educational Goals: To understand reaction rate, concentration and determine the order of a reaction and the rate constant.

Student Objectives: Students will …
• Apply the concepts of reaction rate to a clock reaction.
• Think critically about a process and how it might be improved using green chemistry principles.
Common pedagogies covered
Hands-on learning
Time required (if applicable)
One 45-60 minute class period

Submitted by

Rhianna Kozinski
Safety Precautions, Hazards, and Risk Assessment
Safety Information:
- Goggles should be worn at all times.
- Gloves and aprons may be worn.
- Hand protection should be used when removing glassware from heat.

Disposal Information:
• Solutions are all safe to go down the drain after collected from student groups.
• Always follow district and state disposal rules.
Digital Object Identifier (DOI)
https://doi.org/10.59877/PZWJ6749

File (PDF, PPT, image, etc)

File (PDF, PPT, image, etc)
greening-the-clock-reaction.docx
Creative Commons License
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.