Introduction to Chemistry

Unit Overview

This unit is intended to familiarize students with some essential considerations of laboratory safety. For some students, this may be a review. For others, it will be new. It is prudent to assume that all students will profit from this discussion.

The learning objectives are general safety precautions that students should be familiar with. Other more specific precautions will arise during laboratory activities, and they should be brought to the students' attention at that time.

In addition,students should develop an understanding of the importance of chemistry in society, as well as how society influences the development of chemistry. The modes of thinking sanctioned by a society guide what members of that society look for and how what is seen is interpreted. What is searched for and how what is found is interpreted are key principles in how science and technology develop.

Students can investigate the societal implications of contemporary issues related to chemistry.

Although we think of science as being universal, science and the applications of science are both influenced by culture. How changes in chemical technology and products affect one society might be very different from how they affect another society or culture.

These principles are important to keep in mind throughout the study of chemistry.

Factors of scientific literacy which should be emphasized

Foundational Objectives for Chemistry and the Common Essential Learnings

Recognize safe practices and explain the reason for each practice.

Report to the teacher if contact lenses are worn.
Report any allergies to the teacher.
Identify the location of the fire blanket, fire extinguishers, eye wash station, and any other safety equipment.
Know how to use the safety equipment in the laboratory.
Restrain any loose clothing, jewellery, or hair.
Wear eye protection whenever it is prudent or required.
Maintain a clean, uncluttered work area.
Gather and promptly dispose of any broken glass.
Comply with fire drill regulations.
Check procedures before carrying them out.
Follow accepted principles for dispensing, handling, and disposing of chemicals.
Recognize and minimize the hazards of toxic and corrosive chemicals.
Treat all chemicals as if they were hazardous.
Refrain from pipetting by mouth.
Use care when operating a burner.
Neither bring food into the laboratory, nor consume food while in the room.
Wash hands after chemicals have been handled.

Identify and explain how chemistry affects us.

Discuss how advances in chemistry have led to the development of new products.
Outline the societal impact of new chemical products.
Recognize that advances in chemistry are often driven by societal needs.
Explain the relationship between science and technology.
Identify some issues or problems for which a knowledge of chemistry is important in identifying causes and solutions.
Recognize that some problems can not be solved by science.

Use a wide range of language experiences for developing knowledge of the importance of chemistry. (COM)

Show understanding by providing an alternative rephrasing, drawing a diagram or making a model.
Synthesize ideas gleaned from a variety of sources and media.
Identify critical issues in factual and editorial argumentative messages from both print and non-print media.
Create questions as tools to further understanding of concepts.

Develop an understanding of how knowledge is obtained, evaluated, refined and changed within chemistry. (CCT)

Focus attention on personal knowledge, and gaps in that knowledge.
Reflect upon how knowledge is created, refined and applied in chemistry.

Come to a better understanding of the personal, moral, social, and cultural aspects of chemistry. (PSVS)

Understand how application of chemical principles through technology influences the natural environment.
Establish arguments based on human rights, human needs or the needs of the environment with respect to the use of knowledge about chemical principles.
Explore how moral principles influence judgements about the application of chemical principles.

Develop a positive disposition to life-long learning. (IL)

Cooperate with each other in order to enhance understanding through shared information.
Move from choosing among teacher-directed activities toward creating self-directed activities pertinent to chemistry.
Develop a willingness to take risks as independent learners.
Recognize the inevitability of profound change due to technological innovations and changes in society's values and norms.
Be willing to try to influence change by continuing to learn and apply what is learned.

Suggested activities and ideas for research projects

Adapt an article from What's Happening in Chemistry to use as a case study to introduce the course.
Use Organic Chemistry 2: ASA or Organic Chemistry 2: Polyethylene from the Concepts in Science series. Although the terminology will be beyond most students understanding at this time, most of the concepts and references will be easily understood. Both videos convey the impact of chemistry and the interrelationships of science, technology, society and the environment.
From Sections III, IV, V, IX, and X of the Laboratory Safety Checklist on pages 139-144 of the Science Safety Resource Manual, create a checklist for students to complete. Take time to discuss the reasons for safety rules and the implications of unsafe practices in the laboratory.
Chapters 1 and 2 from Science Process and Discovery contain an excellent introduction to the nature of science. If these chapters were not already used in grade 10, they are well worth using as an introduction to Chemistry 20. The discussion of these chapters can serve as a focal point or a reference point during the rest of the course.
"Chemistry of Consumer Products" from Chemicals in Action may be a useful way to motivate students to study chemistry. Alternatively, there are some problems or questions from the unit Consumer Chemistry in this guide that might be used to introduce the study of chemistry.
When ethanol (or methanol) and saturated calcium acetate solution are mixed in a 5:1 volume ratio, a gel forms. Simultaneously pouring the liquids into a beaker produces sufficient mixing. The gel can be removed from the beaker and burned on a wire mat. Quantities of 5 mL acetate solution and 25 mL alcohol mixed in a 100 mL beaker are enough for each lab group to investigate.

What effects are there when the 5:1 alcohol to acetate ratio is changed? What uses are there for this gel? What are some other examples of gels?
Demonstrate the dehydration of sugar by concentrated sulphuric acid.
Fill a 100 mL beaker to the 40 mL mark with table sugar (sucrose). Ask students to predict what will happen if 40 mL of water is added. Have them record their predictions, or record class predictions on the board. Mix and observe. Repeat the process (predictions and all) using 40 mL of concentrated (18 M) sulphuric acid instead of water. Since SO_2(g)is generated by the reaction between the sugar and the sulphuric acid, do this in a fume hood, a well-ventilated room or outdoors. Concentrated sulphuric acid is extremely corrosive. Handle it with care and have a spill absorbing mixture available. Rinse the carbon column under running water for at least a minute. It can then be disposed of in ordinary garbage.

Discuss the predictions and the results. Linus Pauling said that seeing this demonstration was the initial spark for his interest in chemistry.
Create a poster which describes the risks associated with one chemical or one family of chemicals which are found in your school.
Search through recent issues of newspapers and magazines. Clip any articles or advertisements which deal with chemicals, the chemical industry, chemical research or chemists. Mount these articles on a poster for display.
If you could develop a new chemical for some use, what would that use be? (e.g. a chemical additive to rubber tires to prevent them from wearing out) Are there any chemicals now which do similar things? Has there been any research done on a chemical for the purpose you stated?
Some chemical discoveries have had both positive and negative effects. Pick one chemical which has been synthesized or isolated in the twentieth century and describe its benefits and its drawbacks. Some examples of such chemicals are detergents, ASA, DDT or other insecticides, 2,4-D or other herbicides, vinyl.
Take a piece of loose leaf paper and draw a vertical line to produce two equal columns. Record observations of the following demonstration in the left hand column. Use a separate point for each observation, and two or three lines between points. When the demonstration is complete, write in the right hand column an explanation for each observation.
Note to teachers: This activity is designed to give students a chance to make observations, interpret them and discuss the difference between an observation, inference and conclusion. Set up the demo as in the diagram.

Put 25 mL concentrated nitric acid into flask A. Fill flask B two-thirds full of water. (Five drops of phenolphthalein and enough 1.0 M NaOH solution to produce a medium pink colour are optional.) Put the stopper into flask B. Gently blow through the delivery tube from the stopper which will go into flask A to make sure that the tube is not blocked.
When everyone is ready to start observing, drop a short piece of copper wire or a penny into the acid in flask A and stopper immediately. NO₂ gas forms. It is very irritating to the eyes, mucus membranes and lungs. Make sure the stoppers are securely in place. The water bath should remove almost all of the NO₂ gas, but have a fume hood handy.
If your classroom configuration is such that not all students have a good view of the flask, consider setting up a closed circuit tv network with the camera at the site of the demo and one or more monitors elsewhere. You might also want to videotape this demonstration. Future classes could be shown the apparatus and then the tape of the demo.
(This activity was adapted from CHEM13 NEWS, #192, February 1990, page 4, based on an idea from Judith Putnam of Ellington, CT, reported by Bruce Hemphill of St. Catharines, ON)

Sample ideas for evaluation and for encouraging thinking

Suppose you have a sister in grade 8. One day she asked you what chemistry is. Write a response to her question.
List five practices that you and your classmates follow to make working in your laboratories safer.
List five things you could do to make your work in the laboratory safer than it is now.
Comment on the quotation "Chemistry is the process of finding out what substances are made of and modifying them for our use."
How does chemistry affect the way we live?
"Science is built up with facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house." - Henri Poincaré, a nineteenth century French philosopher and mathematician.

If chemistry is just a matter of remembering a bunch of facts about matter and its structure, and memorizing how to do problems about matter and its changes, then it is like a heap of stones or a pile of brick or a stack of lumber. A house has a structure that is produced by ordered relationships among building materials. Chemistry has a stucture that is produced by ordered relationships among concepts. Matter is made of atoms. Atoms can join together to form molecules. An atom can be manipulated to give up electrons. These are all ideas we believe because of observations that have been made and facts that have been established.

Concept maps or concept webs help us sort out the connection among concepts. So a concept map is one way to express the structure of chemistry as a science, as defined by Poincaré.

Starting with the broad concept chemistry, draw a concept map or web which expresses your ideas about chemistry. Once you have drawn it, find a partner. Compare your maps or webs. Explain them to each other. Then put them away until the end of the term. At that time you will draw another map or web. The two can then be compared. Remember that a concept map is never right or wrong, but it expresses what you understand about a topic.

Teacher's note: A concept map has a hierarchical structure. Thus, the map indicates both the priority and specificity of the concepts diagrammed on it. A concept web has a structure which shows relationships among concepts, but does not attempt to indicate any level of either importance or abstraction. For a complete description of concept mapping, see Novak, J and D. Gowin (1984). Learning How to Learn . New York: Cambridge University Press.