Chemical Reactions and Stoichiometry

The Concord Consortium (Dan Damelin, National Science Foundation grant 0628181)
Type Category
Instructional Materials
Interactive Simulation
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



This series of interactive simulations provide students with the ability to experiment with reaction concentration and temperature to observe the effects on a chemical reaction. This simulation is coupled with questions that lead students to develop a conceptual understanding about how these factors affect reaction rates. This review focuses only on the Day 1 activities within the site, accessed on pages 1-5. In this portion of the lesson,students are directed to explore investigations by accompanying text, questions, goals and specific challenges. The variables of temperature and concentration are addressed separately, and then the student is asked to manipulate both variables together with the size of the container in the end challenge. Simulations can be paused for closer investigation, reset, and replayed numerous times. Multiple choice and short response questions can be saved and sent in a report to the teacher. The simulations do not reference specific temperatures, but ranges qualitatively from low to high.

Intended Audience

Educational Level
  • High School
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

HS-PS1-5 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.

Assessment Boundary: Assessment is limited to simple reactions in which there are only two reactants; evidence from temperature, concentration, and rate data; and qualitative relationships between rate and temperature.

This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.

Comments about Including the Performance Expectation
Students have the opportunity to adjust the temperature and concentration of a group of particles within this simulation, using the pause and reset options to see how the molecules interact. The accompanying short response questions allow students the opportunity to construct explanations in writing, but the multiple choice questions act as stepping stones to understanding the relationship between the variables and reaction rates. This lesson should be supported with discussion of kinetic molecular theory, and additional hands-on activities to show these relationships with quantitative data.

Science and Engineering Practices

This resource was not designed to build towards this science and engineering practice, but can be used to build towards it using the suggestions provided below.

Comments about Including the Science and Engineering Practice
This simulation should be supported with students investigating temperature and concentration of a reaction in a lab activity, where they can collect quantitative data that can be used to mathematically prove the relationship between the variables. For example, groups of students can perform the same reaction at varying temperatures or varying molarities of solution. If designed as an inquiry lab, students would have the opportunity to design a solution using these principles as an extension of this Practice. For example, getting the iodine clock reaction to change at a specific time interval.

This resource appears to be designed to build towards this science and engineering practice, though the resource developer has not explicitly stated so.

Comments about Including the Science and Engineering Practice
Students are able to construct explanations to show how each variable individually impacts the collisions of molecules, which extends to be a reflection of reaction rate. Students are asked to solve a challenge using both variables together within the model.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
The simulation provides opportunities for students to observe collisions between reactants to form products of a chemical reaction. Through experimenting with quantities of reactants and temperature, students are lead to write claims about how these variables affect the rate of the reaction. However, changes in energy are not addressed other than temperature as a form of energy.

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
The simulation allows the student to investigate the relationships between each variable and the collision of particles, which is measured in empirical evidence as the rate of the reaction. There is a direct cause and effect relationship within the simulation interactivity, however, there is little prediction or extension to how this concept may translate to other variables. Teachers can extend this simulation to have students make claim predictions about in- class demonstrations and labs before performing the lab, using evidence from the simulation to support their reasoning.

Resource Quality

  • Alignment to the Dimensions of the NGSS: The disciplinary core idea is directly supported. The practice of constructing explanations and solutions and the crosscutting concept of showing the cause and effect relationship can be supported by student hands-on investigations of a reaction. A teacher could use a supplemental lab activity to provide students with more quantitative data to use to make specific predictions, and support their claims with evidence.

  • Instructional Supports: The simulation does not have many supports. The simulation is text-heavy with a high reading level. Teachers working with English Language Learners would need to provide key vocabulary beforehand, and may consider having students complete the simulation in teams of 2 or 3.

  • Monitoring Student Progress: The students can send reports to their teacher that include their written responses to the short answer questions. However, the multiple choice selections can be changed until correct, so those questions would not be a useful assessment tool.

  • Quality of Technological Interactivity: The simulations on each page run similarly, however, there is a small learning curve in understanding how to play, pause and reset each simulation. The teacher could support students by previewing how to use these features with the class. Simulation must be downloaded to each computer and runs on Java.