Learning Resource Type

Classroom Resource

Energy Changes in Chemical Reactions

Subject Area

Science

Grade(s)

8

Overview

In this lesson, students will conduct two chemical reactions. In the first, the temperature will go down (endothermic), and in the second, the temperature will go up (exothermic). Students will see an animation to show that it takes energy to break bonds and that energy is released when new bonds are formed. Students will use this idea to explain why a reaction is either endothermic or exothermic.

Students will be able to define an endothermic and exothermic reaction. Students will be able to use the concept of energy in bond breaking and bond making to explain why one reaction can be endothermic and another reaction can be exothermic.

    Science (2015) Grade(s): 8

    SC15.8.4

    Design and conduct an experiment to determine changes in particle motion, temperature, and state of a pure substance when thermal energy is added to or removed from a system.

    Unpacked Content

    UP:SC15.8.4

    Vocabulary

    • Particle motion
    • Temperature
    • State [of Matter]
    • Pure substance
    • Thermal Energy
    • Kinetic Energy
    • System

    Knowledge

    Students know:
    • Changes in particle motion of a pure substance occur when thermal energy is added to or removed from a system.
    • Changes in temperature of a pure substance occur when thermal energy is added to or removed from a system.
    • Changes in state of a pure substance occur when thermal energy is added to or removed from a system.

    Skills

    Students are able to:
    • Identify the phenomena under investigation, which includes changes in particle motion, temperature, and state of a pure substance when thermal energy is added to or removed from a system.
    • Identify the purpose of the investigation, which includes determining changes in particle motion, temperature, and state of a pure substance when thermal energy is added to or removed from a system.
    • Develop a plan for the investigation individually or collaboratively.
    • Describe factors used in the investigation including appropriate units (if necessary), independent and dependent variables, controls and number of trials for each experimental condition.
    • Perform the investigation as prescribed by the plan.
    • Use data from the investigation to provide an causal account of the relationship between the addition of removal of thermal energy from a substance and the change in the average kinetic energy of the particles in a substance.

    Understanding

    Students understand that:
    • Adding or removing thermal energy from a system causes changes in particle motion of a pure substance.
    • Adding or removing thermal energy from a system causes changes in temperature of a pure substance.
    • Adding or removing thermal energy from a system causes changes in state of a pure substance.

    Scientific and Engineering Practices

    Planning and Carrying out Investigations

    Crosscutting Concepts

    Systems and System Models
    Link to Resource

    CR Resource Type

    Lesson/Unit Plan

    Resource Provider

    American Chemical Society
    Accessibility
    License

    License Type

    Custom
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