Chemistry (2020)

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

Colligative Properties

Determine how the physical properties of a solvent are dependent on the number of solute particles present. Measure the vapor pressure, boiling point, freezing point, and osmotic pressure of pure water and a variety of solutions. Compare the effects of four solutes (sucrose, sodium chloride, calcium chloride, and potassium chloride) on these physical properties. 5 Minute Preview

Density Laboratory

With a scale to measure mass, a graduated cylinder to measure volume, and a large beaker of liquid to observe flotation, the relationship between mass, volume, density, and flotation can be investigated. The density of the liquid in the beaker can be adjusted, and a variety of objects can be studied during the investigation. 5 Minute Preview

Freezing Point of Salt Water

Control the temperature of a beaker of water. As the temperature drops below the freezing point, a transformation of state will occur that can be viewed on a molecular level. Salt can be added to the water to see its effect on the freezing point of water. 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

Phase Changes

Explore the relationship between molecular motion, temperature, and phase changes. Compare the molecular structure of solids, liquids, and gases. Graph temperature changes as ice is melted and water is boiled. Find the effect of altitude on phase changes. The starting temperature, ice volume, altitude, and rate of heating or cooling can be adjusted. 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

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

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

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

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

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

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

Titration

Measure the quantity of a known solution needed to neutralize an acid or base of unknown concentration. Use this information to calculate the unknown concentration. A variety of indicators can be used to show the pH of the solution. 5 Minute Preview

pH Analysis

Test the acidity of common substances using pH paper. Materials including soap, lemon juice, milk, and oven cleaner can be tested by comparing the color of pH strips to a standard scale. 5 Minute Preview

pH Analysis: Quad Color Indicator

Test the acidity of many common everyday substances using pH paper (four color indicators). Materials including soap, lemon juice, milk, and oven cleaner can be tested by comparing the color of the pH strips to the calibrated scale. 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 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

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

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

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

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

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

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

Nuclear Decay

Observe the five main types of nuclear decay: alpha decay, beta decay, gamma decay, positron emission, and electron capture. Write nuclear equations by determining the mass numbers and atomic numbers of daughter products and emitted particles. 5 Minute Preview

Nuclear Reactions

Explore examples of nuclear fusion and fission reactions. Follow the steps of the proton-proton chain, CNO cycle, and fission of uranium-235. Write balanced nuclear equations for each step, and compare the energy produced in each process. 5 Minute Preview

Temperature and Particle Motion

Observe the movement of particles of an ideal gas at a variety of temperatures. A histogram showing the Maxwell-Boltzmann velocity distribution is shown, and the most probable velocity, mean velocity, and root mean square velocity can be calculated. Molecules of different gases can be compared. 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

Energy of a Pendulum

Perform experiments with a pendulum to gain an understanding of energy conservation in simple harmonic motion. The mass, length, and gravitational acceleration of the pendulum can be adjusted, as well as the initial angle. The potential energy, kinetic energy, and total energy of the oscillating pendulum can be displayed on a table, bar chart or graph. 5 Minute Preview

Inclined Plane - Sliding Objects

Investigate the energy and motion of a block sliding down an inclined plane, with or without friction. The ramp angle can be varied and a variety of materials for the block and ramp can be used. Potential and kinetic energy are reported as the block slides down the ramp. Two experiments can be run simultaneously to compare results as factors are varied. 5 Minute Preview

Boyle's Law and Charles's Law

Investigate the properties of an ideal gas by performing experiments in which the temperature is held constant (Boyle's Law), and others in which the pressure remains fixed (Charles's Law). The pressure is controlled through the placement of masses on the lid of the container, and temperature is controlled with an adjustable heat source. Gay-Lussac's law relating pressure to temperature can also be explored by keeping the volume constant. 5 Minute Preview

Ideal Gas Law

Explore relationships between amount, temperature, pressure, and volume for an ideal gas in a chamber with a moveable piston. Discover rules of proportionality contained in Boyle's law, Charles's law, Avogadro's law, and Gay-Lussac's law. Use these relationships to derive the ideal gas law and calculate the value of the ideal gas constant. 5 Minute Preview

Temperature and Particle Motion

Observe the movement of particles of an ideal gas at a variety of temperatures. A histogram showing the Maxwell-Boltzmann velocity distribution is shown, and the most probable velocity, mean velocity, and root mean square velocity can be calculated. Molecules of different gases can be compared. 5 Minute Preview

Phase Changes

Explore the relationship between molecular motion, temperature, and phase changes. Compare the molecular structure of solids, liquids, and gases. Graph temperature changes as ice is melted and water is boiled. Find the effect of altitude on phase changes. The starting temperature, ice volume, altitude, and rate of heating or cooling can be adjusted. 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

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