Green Chemistry

Demonstrating the Stoichiometry of a Chemical Reaction with Baking Soda and Vinegar

Many students have been introduced to the chemical reaction of baking soda and vinegar throughout their school years. This lab is another way of interpreting the same reaction to visually understand chemical properties and synthesis more clearly. A common way to do this is to stretch a balloon, pre-filled with a certain amount of baking soda, over a flask in which some vinegar has been added. Tipping up the balloon causes the baking soda to mix with the vinegar and the resulting reaction produces gas that pumps up the balloon. Balloons expand to different extents depending on how much carbon dioxide gas is produced and this depends on the quantity of baking soda and vinegar used.

Equipment

Scale (to 0.1 grams)

Erlenmeyer flask (100 ml minimum)

Small Balloons

Baking Soda

Vinegar

Procedure

Read entire document, then ask questions before proceeding with lab

Create a data table for the mass of each object before and after reaction

Mass the empty balloon and the empty flask

Measure out 4 g sodium bicarbonate and place inside balloon.

Add 2 tablespoons of vinegar (30 ml of 5% acetic acid) into a 100 ml flask

Mass the vinegar and flask combination to determine the mass of vinegar

Stretch the mouth of the balloon over the mouth of the bottle then turn the balloon completely upright so that the baking soda inside the balloon pours into the vinegar.

When reaction is complete carefully remove balloon and tie off without letting gas escape.

Take balloon and place on scale to determine mass of gas inside balloon.

Assuming the gas was the only thing desired as a result of the reaction answer the questions in the analysis.

Assuming the following is the reaction for this lab, answer the following:

CH ₃COOH + NaHCO ₃ → CH ₃COONa + H ₂CO ₃

H ₂CO ₃ → H ₂O + CO ₂

Analysis

1. Place balloon with gas on scale to obtain mass of gas and place in data table.
2. Mass contents of flask by placing on scale
3. Add mass of gas and contents of flask to determine full mass of all products.
4. Describe the entire reaction from beginning to end in one short paragraph. Be sure to include temperature change, reaction sequence, what it looks like before and after reaction, etc…
5. Determine if the conservation of mass was achieved by adding mass of all reactants and comparing to mass of all products.
6. Determine the appropriate labels (what is each substance) for the above equations and apply labels by rewriting on your own paper.
7. Determine atom economy for the equation based on the assumption that the trapped gas was the only product that was desired. Use your notes to determine atom economy and show all work for this in molar mass.
8. Based on the efficiency of this synthetic process, extrapolate out the need for 1000 kg of CO ₂ gas using the same synthetic method. What would the amount of waste product be? Is this an efficient process?
9. What in your opinion could be done to improve the efficiency of this reaction to reduce the overall waste? List several.
10. What was left over after the reaction? Was all the vinegar used? How about all the baking soda?
11. What is the new substance in the flask? If the process was not complete, or even if it was, explain why in terms of solubility.

Polymer Ball Lab

Due to limited space available please proceed to the following site for this lab:

teachers.sduhsd.k12.ca.us/ccollins/Polymers lab.doc (public domain site courtesy)

Student advocacy Project

This project is designed to involve you the learner as a valid advocate for support of green chemistry in society. You now have a brief understanding of the principles of green chemistry most notably #'s 1, 2, 10, & 12 from the list of principles of green chemistry (if unsure, look back at your notes now). Using this knowledge of green chemistry, you will embark on a research project that will ultimately put you in contact with one of the following:

A company that does not use the principles of Green Chemistry and is unsure about how to implement them.

A company that has already begun using the principles of green chemistry in their products.

A politician at the state or federal level that has interest in green chemistry and its potential as use in creating new environmental legislation.

You may not know who you will be in contact with as you start this project as the project itself will become a learning exercise and will develop along with your level of education. Remember to use your zealousness as a pro green chemistry advocate every step of the way through this project understanding that no company will be perfect and very few if any chemical processes will be purely green. Instead you will be looking for the adaptation, and to what level the adaptation is being made to adhere, to the principles of green chemistry.

The Project:

A group of three (four when needed based on class size, two when no other choice is available, never solo, and never more than four) students chosen either randomly or by students dependant upon nature of students will form the brain trust of the project.

Each group will look around at their lives and lifestyle and choose one product that is an important part of their daily lives and routines (With the exception of shoes as this has already been discussed in class). Once this project is chosen, whether it be mp3 players, game systems, clothing, jewelry, or some other object students must approach the teacher and get approval of this product before proceeding further.

Research Phase:

Once approval of the project has been established, each person in the group should independently pursue research on the production of the same general product from a variety of manufacturers (i.e. for sneakers you could research Nike, Adidas, Reebok, New Balance, etc…). You want to create a data table of the different raw materials, or chemicals used in the manufacture of the product. This research should also include how these materials are acquired (mined, manufactured at other sites, etc…) and used in the manufacture of the final product for consumer use. Do not forget the packaging that the product comes in, as this is still a part of the manufacturing process. It is better to have more research at this point than too little. Get together and compare data with others in the group periodically to get a thorough education of the manufacturing process of this product, understanding what general wastes are associated with the manufacture of this product. Create a plan for how to address the issues that have been found regarding the manufacture of your chosen product. Conference with the teacher for guidance about findings and what direction the group should focus on from this point forward. This is an important step in this project to ensure a well thought out design.

Address the issues:

Based on the research, subdivide the group into one person to find a political ally in green chemistry. This person should interview a politician or politician's office as to their stance on certain manufacturing processes after you share your valuable education with them about green chemistry. The interview should include questions about policy and potential new legislation that relates to green chemistry and the principles of green chemistry. This interview should be a minimum of ten questions and must be approved by the teacher before the interview can take place. The answers should then be transcribed onto paper, or e-mail the questionnaire to their office after verbal dialogue to have a hard copy of their record.

The other two individuals will pick a company, a person to contact and determine if they are utilizing any practices of green chemistry. This can be done through the education resources of the company, or the companies' public administrator that addresses questions from the public on their manufacturing process. Understand that some questions about green chemistry may be new to them as it is a new science. Act professionally and ask them to get back to you with further clarification of any items they have trouble initially answering. Similar to the person above, this should be achieved by developing a set of interview questions based on the research done on the manufacturing of these products. The questions should be specific rather than general so that the answers can also be specific. Again the questions need to be approved by the teacher before the interview session. The interview again must be transcribed in writing to a hard copy that will eventually be turned in with the final project. With all luck, one person will find a company doing a lot in green chemistry, while the other will not, showing a range in manufacturing. If you find that neither company is doing anything you may want to continue searching for a few more companies to find one that does employ some form of green chemistry in the manufacturing process.

Develop a plan:

The group will have to report their findings back to the class with each person having a five minute report based on their findings. This presentation must have some form of visual aid which could be a display board, computer program such as power point, or an infomercial self-created about the chosen product and its manufacturing process. Data are important to include in this report so charts and diagrams showing waste and efficiency would enhance the overall project. Graded as a group and individually.

Finally the group will have to prepare a written research report describing their entire project from beginning to end. This should be no more than 15 pages total for the entire group and includes the transcribed interviews conducted during the research. This does not include bibliography, acknowledgements, or title and contents page. Graded as group for multiple grades should be written independently for different parts and then combined into one paper.