HS-PS1-6
Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.
Clarification statement: Emphasis is on the application of Le Chatelier’s Principle and on refining designs of chemical reaction systems, including descriptions of the connection between changes made at the macroscopic level and what happens at the molecular level. Examples of designs could include different ways to increase product formation including adding reactants or removing products.
Assessment boundary: Assessment is limited to specifying the change in only one variable at a time. Assessment does not include calculating equilibrium constants and concentrations.
Note: this performance expectation integrates traditional science content with engineering through a Practice or Disciplinary Core Idea.
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-PS1-6.

Assessment
What assessment of HS-PS1-6 might look like on a NY state exam.

NGSS Dimensions
Performance expectation HS-PS1-6 was developed using the following elements from the NRC document A Framework for K-12 Science Education:
- Constructing Explanations and Designing Solutions
- Refine a solution to a complex real-world problem, based on scientific knowledge, student-generated sources of evidence, prioritized criteria, and tradeoff considerations.
- PS1.B: Chemical Reactions
- (NYSED) In many situations, a dynamic and condition dependent balance between a reaction and the reverse reaction determines the numbers of all types of particles present.
- EST1.C: Optimizing the Design Solution
- Criteria may need to be broken down into simpler ones that can be approached systematically, and decisions about the priority of certain criteria over others (tradeoffs) may be needed.
- Stability and Change
- Much of science deals with constructing explanations of how things change and how they remain stable.