Chemical Reactions and Bond Energies


Presentation Description

This is my Digital Unit Plan Proposal. It covers chemical thermodynamics, which includes reaction ethalpies, bonding energies, and combustion reactions (since these reactions typically emit a lot of energy, and are used power our cars and our homes).


Presentation Transcript

Chemical Reactions and Bond Energies:

Chemical Reactions and Bond Energies By Juan Perezchica

Content Standards Addressed (NGSS and CCSS):

Content Standards Addressed (NGSS and CCSS) NGSS.HS-PS1-2 .  Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties . NGSS.HS-PS1-4 .  Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy . NGSS.HS-PS1-7 .  Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.

Content Standards Addressed (NGSS and CCSS):

Content Standards Addressed ( NGSS and CCSS) CCSS.ELA-Literacy.WHST.9-12.2  Write informative/explanatory texts, including the narration of historical events, scientific procedures/experiments, or technical processes. ​ CCSS.Mathematics.MP.2  Reason abstractly and quantitatively. ​ CCSS.Mathematics.MP.4  Model with mathematics.

Big Ideas/Unit Goals and 21st Century Skills:

Big Ideas/Unit Goals and 21 st Century Skills Big Ideas: All chemical reactions produce new substances (products) from previous substances (reactants) and are regulated by the laws of thermodynamics.  Reactions will proceed forward by themselves if they are exergonic, that is if they must  release energy  to produce products.  In contrast, reactions that are endergonic need to  absorb energy  from the environment to be driven forward and produce products . The  required amount of energy  to make products from reactants in a chemical reaction system is identical to the  difference in the sum of bond energies between the products and the reactants  (also known as  change in enthalpy ).  If energy is  released  by the chemical reaction, than the sum of bond energies in the products is less than the sum of bond energies in the reactants.  If energy is absorbed  by the chemical reaction, than the sum of bond energies in the products is greater than the sum of bond energies in the reactants.

Big Ideas/Unit Goals and 21st Century Skills:

Big Ideas/Unit Goals and 21 st Century Skills Unit Goals: Students will conduct lab investigations, explore reliable texts and other types of resources, participate in discussions, and formulate arguments/claims in response to these questions: What happens in a chemical reaction and what must be provided or removed in a chemical reaction system to get it to push forward ? How does the required amount of energy  absorbed  or  released  in a chemical reaction relate to the  difference  in the sum of bond energies between the products and reactants; why?

Big Ideas/Unit Goals and 21st Century Skills:

Big Ideas/Unit Goals and 21 st Century Skills 21 st Century Skills: Students will research the internet for reliable science websites and resources to help them identify the unknown products and thermodynamic nature (including connected bond energies) of a mysterious reaction. Students will engage in an online socrative quiz on Kahoot , with questions pertaining to components involved in a chemical reaction, chemical thermodynamics, and the connection between bond energies and energy released/absorbed. They will need chromebooks /tablets for this activity. Students will use chromebooks to create a detailed and illustrated brochure naming one chemical reagent and a variety of substances it can react with to form numerous useful products. (The chemical reactions and created products must be real.)

Student Learning Objectives and Assessments:

Student Learning Objectives and Assessments Learning Objectives: Students will be able to write a scientific procedure for inquiry-based experimentation involving a mysterious reaction . Students will be able to construct a claim pertaining to the heat flow of a mysterious reaction, based on the chemical equation model they formulate about this reaction through laboratory exploration and research. Students will be able to construct a crude calorimeter, to perform combustion reactions on three food items and obtain the energy content per unit of mass in the food. Assessments: Entry Level: Students will work in pairs to answer introductory questions posted on an online Kahoot game, pertaining to chemical thermodynamics and bond energies; students will assess themselves as the computer scores their selections and compares them to the class average. Formative: On a provided scaffold guide, students will write a claim either about (1) the heat flow of the mysterious reaction, (2) the sum of bonding enthalpies of the products in relation to that of the reactants, or (3) a possible product. Students will have to support this claim with background knowledge and their observations initially. Summative: Students will be given a quiz with 14 items, covering chemical thermodynamics, bonding energies, and combustion reactions.

Two Different Learning Activities:

Two Different Learning Activities Students will get into groups of two and will read an adapted textbook reading on chemical equations, the law of the conservation of mass, reaction enthalpies and bonding energies. They will annotate and highlight the reading. After they read, they will engage in a pair-share activity to discuss what they have learned. Selected pairs of students will explain out loud what the article covered; they will be guided with questions from the teacher. Students will set-up a soda can calorimeter using materials provided by the teacher. Students will be allowed to use a hand-out for guidance and will be allowed to browse the internet for alternative set-ups/additional support. Students will be attentive as the teacher provides feedback on each group’s set-up. Each student will have to keep/fill a data table on the provided scaffold guide as the lab proceeds. The data table will keep track of the mass of each food item before and after combustion occurs (it’s burned), and the highest temperature recorded for the water in the can will also have to be recorded. These values will be necessary for calculations to be performed the following day, pertaining to the energy content of the food items.

Why I Chose This Topic.:

Why I Chose This Topic. I selected this topic because it’s generally a more challenging topic for high school chemistry students. Making the unit on chemical thermodynamics (which includes reaction enthalpies and bonding energies) more of a hands-on exploration (through compelling lab activities) would allow students to make better connections between the content in it than if, say, it was given exclusively as a reading and written assignments. This is why this unit will include both an exploration of a mysterious chemical reaction (in which students are to formulate a claim) and an investigation of food labels and the burning of the connected foods (energy content will be calculated in kilocalories for this activity). I think I can make this unit more interesting for the students, than what is typically encountered with this unit across high school campuses . Because of the addition of these activities, this unit will be a lot more technology-based and require the students to improve their researching skills on the internet, as they search for reliable web information for support. Students will have to rely on technology for multiple activities throughout this lesson. The reliance on technology and the information gathered from these lab activities will get students to see the crucial connection between energies in bonds and how these relate to the energy absorbed or emitted in a chemical reaction (where these bonds are broken and made). This unit will be far less confusing and more informative – which why I selected the activities in it.

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