Is Chemistry Required in High School in Missouri?
To graduate high school in Missouri, students must complete 3 credits of Science with biology, chemistry, and physics with at least one lab class is strongly recommended. According to the Missouri Science Standards, students in Grades 9-12 will cover chemistry topics in their Physical Sciences class such as:
12.PS1.B.1 Chemical Reactions
Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.
[Clarification Statement: Emphasis is on student reasoning that focuses on the number and energy of collisions between molecules. Increasing the temperature increases the kinetic energy of particles. Increasing the number of reactants increases the number of collisions, which increases the reaction rate. Students will analyze data of reaction rates and explain how temperature or concentration affects the rate of reaction.]
Possible Evidence
- Students construct an explanation that includes the idea that as the kinetic energy of colliding particles increases and the number of collisions increases, the reaction rate increases.
- Students identify and describe evidence to construct the explanation, including the following:
- Evidence (e.g., from a data table) of a pattern that increases in concentration (e.g., a change in one concentration while the other concentration is held constant) increases the reaction rate, and vice versa.
- Evidence of a pattern that increases in temperature usually increase the reaction rate, and vice versa
- Students use and describe the following chain of reasoning that integrates evidence, facts, and scientific principles to construct the explanation:
- Molecules that collide can break bonds and form new bonds, producing new molecules.
- The probability of bonds breaking in the collision depends on the kinetic energy of the collision being sufficient to break the bond, since bond breaking requires energy.
- Since temperature is a measure of average kinetic energy, a higher temperature means that molecular collisions will, on average, be more likely to break bonds and form new bonds.
- At a fixed concentration, molecules that are moving faster also collide more frequently, so molecules with higher kinetic energy are likely to collide more often.
- A high concentration means that there are more molecules in a given volume and thus more particle collisions per unit of time at the same temperature.
12.PS1.B.2 Chemical Reactions
Refine the design of a chemical system by specifying a change in conditions that would alter the amount 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. Students will change a variable and explain how that changes equilibrium.]
Possible Evidence
- Students identify and describe potential changes in a component of the given chemical reaction system that will increase the amounts of particular species at equilibrium. Students use evidence to describe the relative quantities of a product before and after changes to a given chemical reaction system (e.g., concentration increases, decreases, or stays the same), and will explicitly use Le Chatelier’s principle, including the following:
- How, at a molecular level, a stressor involving a change to one component of an equilibrium system affects other components.
- That changing the concentration of one of the components of the equilibrium system will change the rate of the reaction (forward or backward) in which it is a reactant, until the forward and backward rates are again equal.
- A description of a system at equilibrium that includes the idea that both the forward and backward reactions are occurring at the same rate, resulting in a system that appears stable at the macroscopic level.
- Students describe the prioritized criteria and constraints, and quantify each when appropriate. Examples of constraints to be considered are cost, energy required to produce a product, hazardous nature and chemical properties of reactants and products, and availability of resources.
- Students systematically evaluate the proposed refinements of the design of the given chemical system. The potential refinements are evaluated by comparing the redesign of the list of criteria (i.e., increased product) and constraints (e.g., energy required, availability of resources).
12.PS1.B.3 Chemical Reactions
Use symbolic representations and mathematical calculations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.
[Clarification Statement: Emphasis is on conservation of matter and mass through balanced chemical equations, use of the mole concept and proportional relationships. Students will be able to demonstrate that the number of products equals the number of reactants.]
Possible Evidence
- Students identify and describe the relevant components in the mathematical representations:
- Quantities of reactants and products of a chemical reaction in terms of atoms, moles, and mass.
- Molar mass of all components of the reaction.
- Use of balanced chemical equation.
- Identification of the claim that atoms, and therefore mass, are conserved during a chemical reaction.
- Mathematical representations may include numerical calculations, graphs, or other pictorial depictions of quantitative information
- Students identify the claim to be supported.
- Students use the mole to convert between the atomic and macroscopic scale in the analysis.
- Given a chemical reaction, students use mathematical representations to predict the relative number of atoms in the reactants versus the products at the atomic-molecular scale.
- Calculate the mass of any component of a reaction, given any other component.
- Students describe how the mathematical representations (e.g., stoichiometric calculations to show that the number of atoms or number of moles is unchanged after a chemical reaction where a specific mass of reactant is converted to product) support the claim that atoms, and therefore mass, are conserved during a chemical reaction.
- Students describe how the mass of a substance can be used to determine the number of atoms, molecules, or ions using moles and mole relationships (e.g., macroscopic to atomic molecular scale conversion using the number of moles and Avogadro’s number).
12.PS1.C.1 Nuclear Process
Use symbolic representations to illustrate the changes in the composition of the nucleus of the atom and the energy released during the processes of fission, fusion, and radioactive decay.
[Clarification Statement: Emphasis is on simple qualitative models, such as pictures or diagrams, and on the scale of energy released in nuclear processes relative to other kinds of transformations. Students can explain how the composition of the nucleus changes.]
Possible Evidence
- Students develop models in which they identify and describe the relevant components of the models, including:
- identification of an element by the number of protons.
- the number of protons and neutrons in the nucleus before and after the decay.
- the identity of the emitted particles (i.e., alpha, beta — both electrons and positrons, and gamma).
- the scale of energy changes associated with nuclear processes, relative to the scale of energy changes associated with chemical processes.
- Students develop five distinct models to illustrate the relationships between components underlying the nuclear processes of 1) fission, 2) fusion, and 3) three distinct types of radioactive decay.
- Students include the following features, based on evidence, in all five models:
- The total number of neutrons plus protons is the same both before and after the nuclear process,
- although the total number of protons and the total number of neutrons may be different before and after.
- The scale of energy changes in a nuclear process is much larger (hundreds of thousands or even millions of times larger) than the scale of energy changes in a chemical process
- Students develop a fusion model that illustrates a process in which two nuclei merge to form a single, larger nucleus with a larger number of protons than were in either of the two original nuclei.
- Students develop a fission model that illustrates a process in which a nucleus splits into two or more fragments that each have a smaller number of protons than were in the original nucleus.
- In both the fission and fusion models, students illustrate that these processes may release energy and may require initial energy for the reaction to take place.
- Students develop radioactive decay models that illustrate the differences in type of energy (e.g., kinetic energy, electromagnetic radiation) and type of particle (e.g., alpha particle, beta particle) released during alpha, beta, and gamma radioactive decay, and any change from one element to another that can occur due to the process.
- Students develop radioactive decay models that describe that alpha particle emission is a type of fission reaction, and that beta emission and gamma emission are not.
Does Missouri Award Credit for Passing the AP Chemistry Exam?
Missouri incentivizes students to take an AP Chemistry course with the hope they can achieve a score that is eligible for college credit on the exam.