Observed patterns of forms and events guide organization and classification, and they prompt questions about relationships and the factors that influence them.
Stability and Change
For natural and built systems alike, conditions of stability and determinants of rates of change or evolution of a system are critical elements of study.
Science & Engineering Practices
Analyzing and Interpreting Data
Once collected, data must be presented in a form that can reveal any patterns and relationships and that allows results to be communicated to others. Because raw data as such have little meaning, a major practice of scientists is to organize and interpret data through tabulating, graphing, or statistical analysis. Such analysis can bring out the meaning of data—and their relevance—so that they may be used as evidence.
Engineers, too, make decisions based on evidence that a given design will work; they rarely rely on trial and error. Engineers often analyze a design by creating a model or prototype and collecting extensive data on how it performs, including under extreme conditions. Analysis of this kind of data not only informs design decisions and enables the prediction or assessment of performance but also helps define or clarify problems, determine economic feasibility, evaluate alternatives, and investigate failures. (NRC Framework, 2012, p. 61-62)
Constructing Explanations and Designing Solutions
The goal of science is the construction of theories that provide explanatory accounts of the world. A theory becomes accepted when it has multiple lines of empirical evidence and greater explanatory power of phenomena than previous theories.”(NRC Framework, 2012, p. 52)
chemical equilibrium - a state that is reached when the rate of the forward reaction equals the rate of the reverse reaction.
dynamic equilibrium - a state of equilibrium in which two opposing processes occur simultaneously with no net change.
equilibrium - a condition in which all acting influences are canceled by others, resulting in a stable, balanced, or unchanging system.
equilibrium constant (ksubeq) - the ratio of the concentration of products divided by the concentration of reactants.
Le Chatelier's Principle - a principle that states that when the equilibrium of a system is disturbed or stressed, the system adjusts to reestablish equilibrium by minimizing or countering the stress.
static equilibrum - a state of equilibrium in which no movement occurs.
The Haber Process - the process of synthesizing ammonia from nitrogen and hydrogen gases.
Georgia Standards of Excellence
SC2Obtain, evaluate, and communicate information about the chemical and physical properties of matter resulting from the ability of atoms to form bonds.
SC2.gDevelop a model to illustrate the release or absorption of energy (endothermic or exothermic) from a chemical reaction system depends upon the changes in total bond energy.
SC4Obtain, evaluate, and communicate information about how to refine the design of a chemical system by applying engineering principles to manipulate the factors that affect a chemical reaction.
SC4.aPlan and carry out an investigation to provide evidence of the effects of changing concentration, temperature, and pressure on chemical reactions. (Clarification statement: Pressure should not be tested experimentally.)
SC4.bConstruct an argument using collision theory and transition state theory to explain the role of activation energy in chemical reactions. (Clarification statement: Reaction coordinate diagrams could be used to visualize graphically changes in energy (direction flow and quantity) during the progress of a chemical reaction.)
SC4.dRefine the design of a chemical system by altering the conditions that would change forward and reverse rates and the amount of products at equilibrium. (Clarification statement: Emphasis is on the application of LeChatelier’s principle.)
Request Teacher Toolkit
The Chemistry Matters teacher toolkit provides instructions and answer keys for labs, experiments, and assignments for all 12 units of study. GPB offers the teacher toolkit at no cost to Georgia educators. Complete and submit this form to request the teacher toolkit. You only need to submit this form one time to get materials for all 12 units of study.