PS1+(Ext)+-+4


 * Students demonstrate an understanding of the structure of matter by …**

__4aa writing an electron configuration to include s, p, d, and f orbitals and relating to atomic interactions.__

__4bb given specific reactants (e.g. Ba + Cl2) write the balanced equation and determine the products, type of compound formed (ionic or molecular), and the properties of the compound (e.g. solubilities, electrolytic, etc).__

PS1 (Ext) - 4 - 4bb Adopted by Shara and Emily

What does this GSE mean?
Students will be able to construct chemical formulas to represent compounds and determine the products formed by interactions of the compounds. They will be able to describe the types of compounds formed and describe the various properties associated with these products.

What subtopics do students need to address to understand this GSE?
- conservation of mass - conservation of charge - reactants vs. products - properties of compounds - balancing chemical equations (stoichiometry) - predicting products - limiting reactants

What ideas to students need to understand before they can address the topics described above?
- difference between atoms and molecules - physical vs. chemical changes - chemical vs. physical properties - periodic table and trends - metals vs nonmetals - bonding (ionic, covalent, metallic) - chemical formulas (ionic, molecular) - molar mass / moles / relationships - Avogadro's Number

What misconceptions are students likely to have about these topics?
- Absence of conservation of particles during a chemical change - Frequent disregard for particle conservation and orderliness when describing physical changes - Failure to perceive that individual substances and properties correspond to a certain type of particle. Formation of a new substance with new properties is seen as simply happening rather than as a result of particle rearrangement - After chemical change, the original substances are perceived as remaining even though they are altered - Size of atoms greatly overestimated: atoms can be seen with a microscope, water molecules are heavy enough to be weighed individually in a high school lab - The original substance vanishes "completely and forever" in a chemical reaction - Freezing and boiling are examples of chemical reactions - Energy is used up in chemical reactions - Energy is created in chemical reactions - Lowest molar amount of reagents is the limiting reagent - Chemical reactions will continue until all the reactants are exhausted - Reactions that proceed more rapidly also proceed further (more completely)

What phenomena and representations help students understand these topics?
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What activities or activity sequences can be used to address these GSEs?
- Students can work in small groups to learn about the chemical composition of common substances. The teacher can given the groups a list of common substances they use every day (shampoo, soap, toothpaste). Students must first predict the elements each substance is made of, and only after that can they research (using the internet), the substances and discover the elements that are actually in the compounds. A brief paragraph can be written about each substance explaining why it is useful and include other interesting facts.

- Ball and stick model kits can be used to help students understand how to balance chemical equations.

- In-class lab activity to learn about chemical reactions: 1. Obtain a tarnished piece of silver. Describe its characteristics. 2. Crumple a small sheet of aluminum foil into a ball. 3. Place the aluminum foil ball into a dishpan filled with soapy water. 4. Position the tarnished piece of silver in the dishpan so that it is underwater and touching the aluminum foil. 5. Wait about 30 minutes then observe the piece of silver. - What happens to the piece of silver? How does it look? - Did a chemical reaction occur? How do you know? - What must occur when silver tarnishes? When it is polished? 6. Silver is tarnished when it is exposed to air, egg white, or rubber bands. Each of these substances contain some form of sulfer. Use this information to describe what happens when silver tarnishes and what happened during this activity.

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 * Concept Map **