Safer, Engaging Chemistry Lessons
Green chemistry. The term conjures different images for different people. Perhaps for the business minded, it’s chemistry dedicated to generating a lot of greenbacks (dollars). For others, maybe it’s a huge cauldron of bubbling green goo with a who-knows-what toxic vapor rising from the brew. In fact, it is neither of these, but green chemistry can save you money and make your lab safer.
Green chemistry refers to the 12 Principles of Green Chemistry, which, when followed, can help you minimize the hazardous substances used in your classroom while providing your students with a rich and complete chemistry experience. The Green Chemistry Principles that can be easily and immediately implemented in a school setting are discussed below.
Prevention: green your lab with smaller sizes
Prevent waste instead of cleaning it up. Buy enough chemical to last only 1 school year. Unexpected changes in curriculum, choice of experiments, or other circumstances outside your control may make the chemical obsolete in your lab next year. We offer many chemicals in small sizes at reasonable prices to help convert your chemical stockroom of aging chemicals to an organized space full of fresh chemicals. Smaller sizes can equal smaller shipping costs. Substances that incur hazardous material shipping charges for larger quantities often ship without the hazardous material charge for smaller sizes (30 g, 30 mL). Look for these smaller sizes when choosing your chemicals.
Whenever possible, switch to a micro scale lab. Perform your experiments on the smallest possible scale. A qualitative experiment will probably scale down successfully. However, experiments demanding precise measurements may also accommodate reductions. Review the experiment to determine if you can reduce the scale. Balance the objective with the chemical demand.
Two good examples of micro scale activities are Carolina’s Mystery Chemical Reactions Kit and Carolina ChemKits®: Making Sense of Solubility. Reactions are completed on a reaction transparency grid using just a couple of drops of each reactant. Cleanup requires just a paper towel.
Safer solvents and auxiliaries: green your lab with solutions prepared for you
Our ready-to-use solutions are premixed for you. These solutions reduce your risk of exposure to pure bulk chemicals and save lab-prep time. If a solute dissolves in water, use an aqueous solution rather than an alcohol solution, sometimes referred to as a tincture. Before using a classic organic solvent, determine if there is a safer alternative. When organic solvents are required, switch to a safer solvent. The chart below will help you make substitutions when appropriate.
Direct Solvent Replacements
| Substance | Replace With | Common Use |
| Cadmium | Copper | Dense metal for density studies |
| Chlorinated Solvents | Ethyl acetate, acetone, or ethanol | Polar, organic solvent |
| Diethyl Ether | Hexane | Non-polar, organic solvent |
| Lead | Copper | Dense metal for density studies |
| Mercury Thermometer | Alcohol Thermometer | Lab Thermometer |
| Methanol | Ethanol | Polar, organic solvent |
| Nitrate Salts | Chloride Salts | Water-soluble metal salts |
| Petroleum Ether | Hexane | Non-polar, organic solvent |
Inherently safer chemistry for accident prevention: green your lab with safer chemicals
Chemicals consistent with the principles of green chemistry are not directly toxic nor do they generate toxic waste. If you are going green, avoid chemicals with health, physical, and environmental hazards. The Molar Mass of a Molecular Compound by Freezing-Point Depression: A “Green” Chemistry Activity is a great example of the “greening” of a standard molar mass determination lab.
You and your students need to be proficient with safety regulations and what is required to run a safe lab. For example, chemical labels must include pictograms compliant with the Globally Harmonized System (GHS) for health, physical, and environmental hazards. Carolina’s print catalog and online chemical product pages include chemical storage codes, California Proposition 65 Warnings, and identification of substances regulated for shipping by the US Department of Transportation (DOT).
We’ve made your selection process easier by identifying green alternatives to hazardous chemicals in the “Notes” of our print and online catalogs’ chemical listings. For example, suppose you plan to purchase sodium nitrate, which our catalogs identify as an oxidizer. The catalogs’ “Notes” list sodium chloride as a green replacement for sodium nitrate. Like sodium nitrate, sodium chloride is a water-soluble salt but does not pose the level of health, physical, and environmental dangers that sodium nitrate poses. Whether the green suggestion will work for you depends on the application. If you are performing double-replacements reactions with sodium nitrate and substitute sodium chloride, you will get nearly the same results at a much lower chemical-exposure risk and lower shipping costs.
See the table below for direct replacements.
Green Chemical Replacements by Substance
| Substance | Replace With |
| Aluminum Nitrate | Aluminum Sulfate |
| Ammonium Nitrate | Ammonium Chloride |
| Calcium Nitrate | Calcium Chloride |
| Chloroform | Ethyl Acetate |
| Cobalt Nitrate | Cobalt Chloride |
| Diethyl Ether | Hexanes |
| Lead | Copper |
| Lithium Nitrate | Lithium Chloride |
| Magnesium Nitrate | Magnesium Chloride |
| Methanol | Ethanol |
| Methylene Chloride | Ethyl Acetate |
| Naphthalene | Lauric Acid |
| Potassium Nitrate | Potassium Chloride |
| Sodium Nitrate | Sodium Chloride |
| Strontium Nitrate | Strontium Chloride |
| Zinc Chloride | Zinc Acetate |
| Zinc Nitrate | Zinc Acetate |
This discussion only addresses 3 of the 12 Green Chemistry Principles, but they are the principles that teachers have control over when making curriculum and materials decisions. Employing the Green Chemistry Principles protects your students, you, and the environment by reducing toxicity and waste, but they can even protect your budget by reducing chemical costs, storage needs, and transportation costs. That’s a win-win!
Resources
- “12 Principles of Green Chemistry” from Figure 4.1: (p. 30). 12 Principles of Green Chemistry from Green Chemistry: Theory and Practice (1998) by Anastas P. and Warner J. By Permission of Oxford University Press.
- American Chemical Society Green Chemistry Institute
- American Chemical Society 12 Principles of Green Chemistry
- EPA Green Chemistry
- EPA Basics of Green Chemistry
- Beyond Benign
Green Chemistry Journals
- Green Chemistry–The home of cutting-edge research on the development of alternative sustainable technologies: https://www.rsc.org/journals-books-databases/about-journals/green-chemistry/
- Clearinghouse of journals and conferences: https://www.omicsonline.org/green-chemistry-journals-conferences-list.php
