Science Einstein

Atom Economy –
1) The mass of desired product divided by the total mass of all reagents, times 100

Mass of Desired Product
Total Mass of all Reagents

Percent Atom Economy = x 100
2) The mass of desired product divided by the total mass of all products and
byproducts produced, times 100
3) A measure of the efficiency of a reaction

Green Chemistry
1) Designing chemical products and processes to reduce or eliminate the use or
generation of hazardous materials
2) Using chemistry for pollution prevention
3) Benign by design, sustainable chemistry

Molecular Weight – mass of one mole of a compound (units of grams per mole)

Percent Yield – actual yield divided by theoretical yield times 100

Theoretical Yield – the maximum amount of product that can be produced from the
quantities of reactants used; the amount of a given product formed when the
limiting reactant is completely consumed

Saponification – the decomposition of triglycerides with aqueous sodium hydroxide

Stoichiometry – application of the laws of definite proportions and conservation of mass to chemical processes; quantitative relationship between compounds involved in
a reaction

Talking Trash—Solid Wastes

Objectives
1) Analyze trends in the generation and reclamation of solid wastes within the United States over time.

Green Chemistry Principles
It’s midnight. Do you know where your product is?
Wastes? Why make them?

IL State Standards (Science)
11.A.3e, 11.A.3f, 11.A.3g, 11.A.4a, 11.A.4d, 12.E.3c, 13.B.4d

For Data Table, go to http://www.greeningschools.org/docs/TalkingTrash.pdf

Vocabulary
Municipal solid waste (MSW), biodegradable, composting, landfill, source reduction

Materials
Graph paper, chalkboard, whiteboard, flipchart or graphing software

Time
One class period

This material is adapted from the ACS text Introduction to Green Chemistry. See the “references” section of the introduction to this manual for additional information on this text.
Background/Overview
We discard many different types of “waste” every day, and yet we seldom stop to think about what happens when we throw things “away”—what do we really even mean by “away?” What is the impact of all the “stuff” we throw “away” once it gets there? The principles of green chemistry are meant to encourage people to think about the fate of the products they create, and to reinforce the idea that nothing every really goes “away.” If our products are not biodegradable (able to be broken down by organisms in the environment, such as bacteria or fungi) or recyclable, what will we do with them? Will any of our wastes be potentially harmful? Once we consider the fate of our products, we can also consider modifying our actions so we end up producing less waste to deal with, or at least producing types of waste that are easier and safer to deal with. In this exercise, students will examine data on the amounts of municipal solid waste generate and recovered in the U.S. over time, as one illustration of the importance of considering the fate of the products we create and dispose of.

The U.S. Environmental Protection Agency (EPA) gathers data every year on the quantity of municipal solid waste (MSW)—otherwise known as garbage, trash, and junk—generated in the United States. MSW consists of items such as product packaging, grass clippings, furniture, clothing, bottles, food scraps, newspapers, appliances, paint, and batteries (see table).

Activity and questions for discussion
1) Prepare a bar chart of total quantity of solid waste generated (shown in the row labeled “Generation”) for each year shown in the table, using graph paper, graphing software, or simply drawing on the chalkboard as a class. Discuss the trend indicated by your graph and possible reasons for this trend.
2) What percentage of solid waste was recycled in 1960 versus 1999? What are some possible reasons for the change?
3) What is composting? Look up information on this if you are not sure. Why would composting of yard trimmings and food waste be a better method of disposal rather than burying these wastes underground in a landfill?
4) In 1960, the quantity of solid waste generated per person per day was 2.68 pounds. By 1999, it had increased to 4.62 pounds. What are the implications of continuing this trend? List some ways of reducing the quantity of waste generated.