StemScopes Chemistry (2021)

Average Atomic Mass

The atomic mass for each element listed in the periodic table is actually the weighted average mass of all of the different isotopes of the element. In the Average Atomic Mass Gizmo, use a mass spectrometer to separate an element into its isotopes. Then, calculate the average atomic mass by considering the mass and abundance of each isotope. 5 Minute Preview

Bohr Model of Hydrogen

Shoot a stream of photons through a container of hydrogen gas. Observe how photons of certain energies are absorbed, causing the electron to move to different orbits. Build the spectrum of hydrogen based on photons that are absorbed and emitted. 5 Minute Preview

Bohr Model: Introduction

Fire photons to determine the spectrum of a gas. Observe how an absorbed photon changes the orbit of an electron and how a photon is emitted from an excited electron. Calculate the energies of absorbed and emitted photons based on energy level diagrams. The light energy produced by the laser can be modulated, and a lamp can be used to view the entire absorption spectrum at once. 5 Minute Preview

Covalent Bonds

Choose a substance, and then move electrons between atoms to form covalent bonds and build molecules. Observe the orbits of shared electrons in single, double, and triple covalent bonds. Compare the completed molecules to the corresponding Lewis diagrams. 5 Minute Preview

Electron Configuration

Create the electron configuration of any element by filling electron orbitals. Determine the relationship between electron configuration and atomic radius. Discover trends in atomic radii across periods and down families/groups of the periodic table. 5 Minute Preview

Electrons and Chemical Reactions - High School

The Secret Service has arrested suspects accused of counterfeiting coins from 1915 valued at $50,000 each. The students act as a forensic scientist to investigate the crime scene and examine the evidence. Students learn about electrons and chemical reactions to recreate the methods used to make the coins and prepare evidence for the court case. Video Preview

Element Builder

Use protons, neutrons, and electrons to build elements. As the number of protons, neutrons, and electrons changes, information such as the name and symbol of the element, the Z, N, and A numbers, the electron dot diagram, and the group and period from the periodic table are shown. Each element is classified as a metal, metalloid, or nonmetal, and its state at room temperature is also given. 5 Minute Preview

Ionic Bonds

Simulate ionic bonds between a variety of metals and nonmetals. Select a metal and a nonmetal atom, and transfer electrons from one to the other. Observe the effect of gaining and losing electrons on charge, and rearrange the atoms to represent the molecular structure. Additional metal and nonmetal atoms can be added to the screen, and the resulting chemical formula can be displayed. 5 Minute Preview

Periodic Trends

Explore trends in atomic radius, ionization energy, and electron affinity in the periodic table. Measure atomic radius with a ruler and model ionization energy and electron affinity by exploring how easy it is to remove electrons and how strongly atoms attract additional electrons. View these properties on the whole periodic table to see how they vary across periods and down groups. 5 Minute Preview

Balancing Chemical Equations

Balance and classify five types of chemical reactions: synthesis, decomposition, single replacement, double replacement, and combustion. While balancing the reactions, the number of atoms on each side is presented as visual, histogram, and numerical data. 5 Minute Preview

Chemical Changes

Chemical changes result in the formation of new substances. But how can you tell if a chemical change has occurred? Explore this question by observing and measuring a variety of chemical reactions. Along the way you will learn about chemical equations, acids and bases, exothermic and endothermic reactions, and conservation of matter. 5 Minute Preview

Chemical Equations

Practice balancing chemical equations by changing the coefficients of reactants and products. As the equation is manipulated, the amount of each element is shown as individual atoms, histograms, or numerically. Molar masses of reactants and products can also be calculated and balanced to demonstrate conservation of mass. 5 Minute Preview

Covalent Bonds

Choose a substance, and then move electrons between atoms to form covalent bonds and build molecules. Observe the orbits of shared electrons in single, double, and triple covalent bonds. Compare the completed molecules to the corresponding Lewis diagrams. 5 Minute Preview

Electrons and Chemical Reactions - High School

The Secret Service has arrested suspects accused of counterfeiting coins from 1915 valued at $50,000 each. The students act as a forensic scientist to investigate the crime scene and examine the evidence. Students learn about electrons and chemical reactions to recreate the methods used to make the coins and prepare evidence for the court case. Video Preview

Ionic Bonds

Simulate ionic bonds between a variety of metals and nonmetals. Select a metal and a nonmetal atom, and transfer electrons from one to the other. Observe the effect of gaining and losing electrons on charge, and rearrange the atoms to represent the molecular structure. Additional metal and nonmetal atoms can be added to the screen, and the resulting chemical formula can be displayed. 5 Minute Preview

Moles

Understand the definition of a mole and determine the Avogadro constant by adding atoms or formula units to a balance until the mass in grams is equal to the atomic or formula mass. Manipulate a conceptual model to understand how the number of particles, the number of moles, and the mass are related. Then use dimensional analysis to convert between particles, moles, and mass. 5 Minute Preview

Stoichiometry

Solve problems in chemistry using dimensional analysis. Select appropriate tiles so that units in the question are converted into units of the answer. Tiles can be flipped, and answers can be calculated once the appropriate unit conversions have been applied. 5 Minute Preview

Melting Points

Every substance has unique transition points, or temperatures at which one phase (solid, liquid, or gas) transitions to another. Use a realistic melting point apparatus to measure the melting points, boiling points, and/or sublimation points of different substances and observe what these phase changes look like at the microscopic level. Based on the transition points, make inferences about the relative strengths of the forces holding these substances together. 5 Minute Preview

Polarity and Intermolecular Forces

Combine various metal and nonmetal atoms to observe how the electronegativity difference determines the polarity of chemical bonds. Place molecules into an electric field to experimentally determine if they are polar or nonpolar. Create different mixtures of polar and nonpolar molecules to explore the intermolecular forces that arise between them. 5 Minute Preview

Sticky Molecules

Learn about molecular polarity and how polarity gives rise to intermolecular forces. Measure four macroscopic properties of liquids (cohesion, adhesion, surface tension, and capillary rise). Compare these properties for different liquids and relate them to whether the substances are polar or nonpolar. 5 Minute Preview

Equilibrium and Concentration

Observe how reactants and products interact in reversible reactions. The initial amount of each substance can be manipulated, as well as the pressure on the chamber. The amounts, concentrations, and partial pressures of each reactant and product can be tracked over time as the reaction proceeds toward equilibrium. 5 Minute Preview

Equilibrium and Pressure

Observe how reactants and products interact in reversible reactions. The amounts of each substance can be manipulated, as well as the pressure on the chamber. This lesson focuses on partial pressures, Dalton's law, and Le Chatelier's principle. 5 Minute Preview

Ocean Carbon Equilibrium - High School

Mussel farmers in the Arctic Ocean have reported problems with their mussels. They have noticed that the mussel shells have eroded and become brittle. Students take on the role of a marine chemist to analyze the changes to ocean carbon chemistry and equilibrium to determine the cause of the mussel shell erosion. Video Preview

Chemical Changes

Chemical changes result in the formation of new substances. But how can you tell if a chemical change has occurred? Explore this question by observing and measuring a variety of chemical reactions. Along the way you will learn about chemical equations, acids and bases, exothermic and endothermic reactions, and conservation of matter. 5 Minute Preview

Collision Theory

Observe a chemical reaction with and without a catalyst. Determine the effects of concentration, temperature, surface area, and catalysts on reaction rates. Reactant and product concentrations through time are recorded, and the speed of the simulation can be adjusted by the user. 5 Minute Preview

Feel the Heat

Have you ever used a glove warmer to keep your hands warm? How about an instant cold pack to treat an injury? In the Feel the Heat Gizmo, create your own hot and cold packs using various salts dissolved in water and different bag materials. Learn about exothermic and endothermic processes and how energy is absorbed or released when bonds are broken and new bonds form. 5 Minute Preview

Reaction Energy

Exothermic chemical reactions release energy, while endothermic reactions absorb energy. But what causes some reactions to be exothermic, and others to be endothermic? In this simulation, compare the energy absorbed in breaking bonds to the energy released in forming bonds to determine if a reaction will be exothermic or endothermic. 5 Minute Preview

Dehydration Synthesis

Build a glucose molecule, atom-by-atom, to learn about chemical bonds and the structure of glucose. Explore the processes of dehydration synthesis and hydrolysis in carbohydrate molecules. 5 Minute Preview

Cell Energy Cycle

Explore the processes of photosynthesis and respiration that occur within plant and animal cells. The cyclical nature of the two processes can be constructed visually, and the simplified photosynthesis and respiration formulae can be balanced. 5 Minute Preview

Cell Respiration - High School

As a medical toxicologist, students learn about cell respiration to save the life of a CIA agent that has been poisoned. Video Preview

Photosynthesis - High School

As a marine biologist students learn about photosynthesis to help scientists in Australia determine why the coral in the Great Barrier Reef is bleaching. Video Preview

Plants and Snails

Study the production and use of gases by plants and animals. Measure the oxygen and carbon dioxide levels in a test tube containing snails and elodea (a type of plant) in both light and dark conditions. Learn about the interdependence of plants and animals. 5 Minute Preview

Calorimetry Lab

Investigate how calorimetry can be used to find relative specific heat values when different substances are mixed with water. Modify initial mass and temperature values to see effects on the system. One or any combination of the substances can be mixed with water. A dynamic graph (temperature vs. time) shows temperatures of the individual substances after mixing. 5 Minute Preview

Energy Conversion in a System

A falling cylinder is attached to a rotating propeller that stirs and heats the water in a beaker. The mass and height of the cylinder, as well as the quantity and initial temperature of water can be adjusted. The temperature of the water is measured as energy is converted from one form to another. 5 Minute Preview

Heat Transfer by Conduction

An insulated beaker of hot water is connected to a beaker of cold water with a conducting bar, and over time the temperatures of the beakers equalize as heat is transferred through the bar. Four materials (aluminum, copper, steel, and glass) are available for the bar. 5 Minute Preview