HS-PS1-4 | Energy in Reactions
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.
Performance Level Descriptions
PLDs communicate the knowledge and skills expected of students to demonstrate proficiency in each Learning Standard. NYS assessments classify student performance into one of five levels.
Resources
Examples and discussion of resources for the learning, teaching, and assessment of HS-PS1-4.

Assessment
What assessment of HS-PS1-4 might look like on a NY state exam.

NGSS Dimensions
Performance expectation HS-PS1-4 was developed using the following elements from the NRC document A Framework for K-12 Science Education:
- Develop and using models: develop a model based on evidence to illustrate the relationships between systems or between components of a system.
- Structure and properties of matter: 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.
- Chemical reactions: chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of particles and the rearrangements of particles into new substances, with consequent changes in the sum of all bond energies in the set of substances that are matched by changes in energy.
- Energy and matter: changes of energy and matter in a system can be described in terms of energy and matter flows into, out of, and within that system.