Physical Science: Chemical Reactions
Unit Overview
Chemistry is the science that answers questions about the composition, structure, and properties of matter and the changes matter undergoes. It has a specialized language based on chemical names, formulas, and equations that are common throughout the world. Students have previously studied physical changes in matter, the structure of the atom, and the periodic table as part of their physical science studies.
In this unit, students investigate the ways in which chemicals interact to form new substances with different properties and relate the patterns of those reactions to the periodic table. Students learn to represent chemical reactions using symbols and word equations. Upon completion of this unit, students should be able to apply their understanding of the Law of Conservation of Mass to write balanced chemical equations to represent chemical reactions.
There is considerable opportunity for students to explore the relationships between science, technology, society, and the environment by investigating the role of acids and bases in the environment and exploring chemical reactions that are common in Saskatchewan agriculture and industry.
Safety in the classroom, workplace, and environment is an important focus of the unit.
K-12 Related Topics in Science
Saskatchewan Science Units (2005)
Grade 1 - Classifying Matter (Optional)
Grade 3 - Properties of Matter
Grade 3 - Fire and Fuels (Optional)
Grade 5 - Matter and Its Changes
Grade 6 - Chemicals and Reactions
Grade 7 - Temperature and Heat (Optional)
Grade 8 - Solutions
Grade 9 - Chemistry and You
Grade 11 - Atoms and Elements
Grade 11 - Molecules and Compounds
Grade 11 - Chemical Reactions
Grade 11 - Mole Concept and Stoichiometry
Grade 11 - Consumer Chemistry (Optional)
Grade 11 - Organic Chemistry (Optional)
Grade 12 - Energy Changes in Chemical Reactions
Grade 12 - Reaction Kinetics
Grade 12 - Equilibrium
Grade 12 - Acid-Base Equilibria
Grade 12 - Oxidation and Reduction
Pan-Canadian Framework Units
Grade 5 - Properties and changes of materials
Grade 7 - Mixtures and solutions
Grade 7 - Heat
Grade 9 - Atoms and Elements
Grade 10 - Chemical Reactions
Grade 11/12 - Organic Chemistry
Grade 11/12 - Acids and Bases
Grade 11/12 - From Structures to Properties
Grade 11/12 - Electrochemistry
Grade 11/12 - Solutions and Stoichiometry
Grade 11/12 - Thermochemistry
Key Questions
- What are chemical reactions, and how do they differ from physical changes?
- How are chemical reactions important in our lives and community?
- How can chemical reactions be represented using words, symbols, and equations?
- What energy changes take place during chemical reactions?
- What factors influence the rate of chemical reactions?
- How does the reliance on fossil fuels affect our society?
- What is the importance of acids and bases in our lives?
Key Concepts
- A chemical reaction involves the rearrangement of atoms to produce different substances.
- Chemical reactions either release or consume energy. Some reactions such as the burning of fossil fuels release large amounts of energy in the form of heat and light. Light can initiate many chemical reactions such as photosynthesis and the evolution of urban smog.
- A large number of important chemical reactions involve the transfer of hydrogen ions (acid/base reactions) between reacting ions, molecules, or atoms.
- Chemical reactions can take place in intervals ranging from femtoseconds (10-15 seconds) to geologic time scales of billions of years. Reaction rates depend on how often the reacting atoms and molecules encounter one another, on the temperature of the reactants, and on certain physical properties - including shape - of the reacting substances.
- Catalysts are substances that increase the rate of a chemical reaction without being consumed in the reaction. Chemical reactions in living systems are catalyzed by protein molecules called enzymes.
- The Law of Conservation of Mass states that in a chemical reaction the total mass of reactants is equal to the total mass of the products.
Suggested Themes
The study of chemical reactions should focus on chemistry in a student's daily life in Saskatchewan, which may include themes such as household chemistry, food chemistry, agriculture, pharmaceuticals, photography, arts and crafts, personal care products, home maintenance products, pesticides, potash, water resources, sodium sulfate, ethanol, ammonia and urea, mining, forestry, or high technology industries.