Unpacked Content
Scientific and Engineering Practices
Constructing Explanations and Designing Solutions
Crosscutting Concepts
Stability and Change
Knowledge
Students know:
- Various stresses made at the macroscopic level, such as change in temperature, pressure, volume, concentration, affect a chemical system at the molecular level.
- Reaction rates of forward/ backward reactions change with stresses until rates are equal again.
- Forward/ reverse reactions occur at the same rate in dynamic equilibrium, so chemical systems appear stable at macroscopic level.
- The egineering design process is a cycle with no official starting or ending point, and, therefore, can be used repeatedly to refine your work.
Skills
Students are able to:
- Use the engineering design process (ask, imagine, plan, create, improve) to refine a chemical system.
- Refine a solution to a complex real-world problem, based on scientific knowledge, student-generated sources of evidence, prioritized criteria, and tradeoff considerations.
- Construct and revise an explanation based on valid and reliable evidence obtained from a variety of sources (including students' own investigations, models, theories, simulations, and peer review).
- Construct and present arguments supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for a phenomenon or a solution to a problem.
Understanding
Students understand that:
- Much of science deals with constructing explanations of how things change and how they remain stable.
- Solutions to real-world problems can be refined using scientific knowledge, student-generated sources of evidence, prioritized criteria, and tradeoff considerations.
- In many situations, a balance between a reaction and the reverse reaction determines the numbers of all types of molecules present.
- Criteria may need to be broken down into simpler ones and decisions about the priority of certain criteria over others (tradeoffs) may be needed.
Vocabulary
- system
- dynamic equilibrium
- stresses
- LeChatelier's principle
- criteria
- constraints
- reversible reaction
- forward/ backward rates
- macroscopic level
- atomic/ molecular level
- claim
- evidence
- reasoning