CR3 Identify characteristics of chemical reactions involving organic compounds

Suggested time: 3-5 hours

Learning Objectives

1. Observe and describe the combustion process.
   
2. Illustrate, using chemical formulas, a variety of natural and synthetic compounds that contain carbon.
   
3. Defend a decision or judgement related to the use of fossil fuels and demonstrate that relevant arguments can arise from different perspectives. (PSD, COM)
   
4. Propose alternative solutions to society's reliance on fossil fuels, identify the potential strengths and weaknesses of each solution, and select one as the basis for a plan. (CCT, PSD)
   
5. Use factual information and rational explanations when analysing and evaluating perspectives related to the use of fossil fuels. (CCT)
   

Key Questions

1. What are the key characteristics of organic compounds?
   
2. What are the products of hydrocarbon combustion?
   
3. What are the dangers of incomplete combustion of a hydrocarbon?
   
4. Why is there concern in our society about the combustion of fossil fuels?
   

Key Concepts

• Organic compounds are molecular substances that contain carbon, excluding carbonates and oxides.
  
• Hydrocarbons are organic compounds composed solely of hydrogen and carbon atoms.
  
• Combustion is the reaction of a substance with oxygen to produce oxides, light and heat. Most combustion reactions involve organic compounds.
  
• Incomplete combustion occurs when there is not enough oxygen available for a combustion reaction which leads to the production of carbon monoxide instead of or in addition to carbon dioxide, when burning a hydrocarbon.
  
• Scientific and technological developments have real and direct effects on every person's life. Some effects are desirable; some are not.
  
• Scientific thought and knowledge can be used to support different positions. Scientists may disagree even though they may invoke the same scientific theories and data.
  
• Science is based on evidence, developed privately by individuals or groups, that is shared publicly with others. This enables others to attempt to establish the validity and reliability of the evidence.
  
• All branches of science are interrelated.
  
• Applications of scientific knowledge and of technological products and practices are ultimately determined by society. Scientists and technologists have a responsibility to inform the public of the possible consequences of such applications.
  

Pre-Instructional Questions

1. Do the students know the difference between organic and inorganic compounds?
   
2. Are the students able to provide examples of organic compounds in their daily lives?
   
3. Are the students able to name examples of hydrocarbons?
   
4. Are the students aware of the location of Canada 's primary hydrocarbon resources?
   

Suggested Teaching Strategies and Activities

1. Students should identify common organic compounds that are present in students' daily lives in order to gain an appreciation of the prevalence of organic compounds. Students could categorize these compounds according to criteria such as use (e.g., fuels, lubricants, detergents, synthetic fibres, plastics, and rubbers). Individual students or groups of students could research the uses of these and other common organic compounds.
   
   
2. Students could describe examples of the combustion process that students see in their daily lives (e.g., propane or natural gas BBQ, automobile gasoline, diesel fuel for a generator, butane curling iron or lighter) as well as examples which may be less readily observable (e.g., oil refinery, industrial manufacturing).
   
   
3. Students should observe the combustion process through the burning of hydrocarbons (e.g., a propane or natural gas BBQ, or Bunsen burner). Students should identify the reactants and products of a typical combustion reaction and the nature of energy changes during these reactions. Students should write the general word equation and a balanced chemical equation for combustion reactions in general (i.e., hydrocarbon + oxygen ® carbon dioxide + water + energy) and for specific combustion reactions (e.g., methane, propane, butane). Students should also be able to describe the origin of the energy that is released during the combustion process.
   
   
4. Students could construct models of common organic compounds (e.g., methane, propane, butane, octane, methanol, ethanol, and glucose) using objects such as Styrofoam balls, marbles, marshmallows, or commercial molecular model kits. As an enrichment activity, students might use the models to identify patterns in the ratios of the elements in organic compounds.
   
   
5. Students could research Canada 's primary hydrocarbon resources (i.e., gas and oil fields in Western Canada, the Alberta Tar Sands, and Hibernia ) and explain why these resources exist in these particular locations. Additionally, students could identify issues related to the use of fossil fuels and the advantages and disadvantages of this resource. Students could also develop a plan for alternatives to fossil fuels for public and private transportation. (IL, PSD, CCT)
   
   
6. Students should research the effects of the use of fossil fuels and then write a position paper, conduct a deliberative dialogue, or participate in a debate in which they defend a position related to the implications of burning fossil fuels in Saskatchewan . Students should express ideas and reactions in an appropriate manner. (IL, PSD, CD 2.3)
   
   
7. Enrichment: Students could research societal and environmental effects of using polymers (e.g., polyurethane, rubber, Lycra, polypropylene, polyethylene, aspartame, saccharine, linoleum) for products such as clothing, diapers, contact lenses, grocery bags, floor coverings, or artificial sweeteners.