Module: Modeling Conservation of Energy
DCI: PS1.A (D) A stable molecule has less energy than the same set
of atoms separated; one must provide at least this energy in order to take the
molecule apart.
PE: 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.
[Clarification
Statement: Emphasis is on the idea that a chemical reaction is a system that
affects the energy change. Examples of models could include molecular-level
drawings and diagrams of reactions, graphs showing the relative energies of
reactants and products, and representations showing energy is conserved.]
[Assessment Boundary: Assessment does not include calculating the total bond
energy changes during a chemical reaction from the bond energies of reactants
and products.]
The basic content of the standard is as follows.
- Stable molecules have less energy than the atoms of which they are made.
- In order to break a stable molecule down into the atoms of which it is comprised, you have to add energy.
- Kids need to have a general concept of how energy is released or absorbed during chemical reactions, depending on the change to bonds.
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