IV. CHEMISTRY TOPICS

 

  1. Inquiry, Reflection, and Social Implications
  2. Forms of Energy
  3. Energy Transfer and Conservation
  4. Properties of Matter
  5. Changes in Matter

 

Additional Sites for Chemistry

  1. Teaching Units / Lesson Plans
  2. Student Activities / Projects / Interactive Sites
  3. Information / Facts / Data / Reports
  4. Videos / Movies / Animations
  5. Photographs / Slides / Diagrams / Graphics
  6. Periodicals / Journals / Newspapers
  7. Searches / Explorations / Investigations
  8. Physical Science Topics for Teachers

 

C2. Forms of Energy

High School

P2.p1 Potential Energy (prerequisite)
Three forms of potential energy are gravitational, elastic, and chemical. Objects can have elastic potential energy due to their compression or chemical potential energy due to the arrangement of the atoms. (prerequisite)

  1. Bang! Boing! Pop! Energy
    This site covers how we can calculate kinetic and potential energy using formulas. This site is a great site about energy, and covers a variety of energy topics.
  2. Changes of Phase (or State)
    When a substance changes from one state, or phase, of matter to another we say that it has undergone a change of state, or we say that it has undergone a change of phase. This site does a nice job of explaining vaporization, evaporation, condensation, sublimation, freezing, and melting.
  3. Changes of State: Solids, Liquids, and Gases
    Any substance, called matter, can exist as a solid material, liquid, or gas. These three different forms are called states. Matter can change its state when heated.
  4. Energy Kid's Page
    Energy is found in different forms, such as light, heat, sound and motion. There are many forms of energy, but they can all be put into two categories: kinetic and potential.
  5. Chem 4 Kids
    Excellent site for beginning students and review of chemistry (reactions, states of matter, elements, units, etc...). There is a quiz and a few other student interactions.
  6. Energy
    Here your students can learn about the changes between potential, kinetic and heat energy through text, a series of hands on classroom activities and even an online "Monkey Swing" game.
  7. Heat and Temperature Discusses heat transfer with animations on the motion of gas molecules, relation to kinetic energy and more links.

C2.1x Chemical Potential Energy
Potential energy is stored whenever work must be done to change the distance between two objects. The attraction between the two objects may be gravitational, electrostatic, magnetic, or strong force. Chemical potential energy is the result of electrostatic attractions between atoms.

  1. Chemical Bonding Home Page
    This site contains a set of textbook-like tutorials covering this important subject, but doing so in a manner that will be both more understandable and more complete than you will find in most current General Chemistry textbooks.
  2. Chemical Energy
    The energy held in the covalent bonds between atoms in a molecule is called chemical energy. This site explains the nature of chemical energy.
  3. Chemistry Tutorial - Chemical bonds and attractive forces
    A molecule is two or more atoms linked by a chemical bond. Molecules can contain different types of bonds. If atoms are sharing electrons, then the bond between them is covalent. If an atom gives up an electron to another atom, then they have an ionic bond.
  4. Potential Energy During Bond Formation
    This site explains potential energy changes as two elements approach one another during bond formation.

C2.2 Molecules in Motion
Molecules that compose matter are in constant motion (translational, rotational, vibrational). Energy may be transferred from one object to another during collisions between molecules.

  1. Basic Terminology and Concepts
    There are many forms of kinetic energy - vibrational (the energy due to vibrational motion), rotational (the energy due to rotational motion), and translational (the energy due to motion from one location to another). This site demonstrates the nature of kinetic energy.
  2. Changes of Phase (or State)
    When a substance changes from one state, or phase, of matter to another we say that it has undergone a change of state, or we say that it has undergone a change of phase. This site does a nice job of explaining vaporization, evaporation, condensation, sublimation, freezing, and melting.
  3. Changes of State: Solids, Liquids, and Gases
    Any substance, called matter, can exist as a solid material, liquid, or gas. These three different forms are called states. Matter can change its state when heated.
  4. Molecular Motion in Solids, Liquids, and Gases
    This site contains an animation showing the different motions and spacings of particles in the three different states of matter.
  5. Molecular Motion of Metal Atoms
    This site provides the student with an animation showing the increase in molecular motion of metal atoms as temperature increases.
  6. Molecules in Motion Applet
    This interactive applet allows the students to modify the number, temperature, and mass of particles as they move. Resulting changes in speed can be investigated.

C2.2x Molecular Entropy
As temperature increases, the average kinetic energy and the entropy of the molecules in a sample increases.

  1. Bond Enthalpy
    The Bond Enthalpy is the energy required to break a chemical bond. The site gives a detailed explanation of bond breaking and bond formation.
  2. Chemical Thermodynamics
    Changes in energy -- however measured, whether it be heat, light, work, etc. -- are clearly physical events that also have a chemical nature to them. Five topics related to energy are discussed here.
  3. Example Questions for the Combined Gas Law
    The combined gas law states that for a closed system (constant moles of gas), the PV product divided by the absolute temperature is constant or P1V1/T1=P2V2/T2. This page provides problems utilizing this relationship. When you press "New Problem",a question will appear to the right of the table. Determine the value of the answer, enter it in the cell and press "Check Answer".
  4. Molecular Entropy
    This site has several animations that show different types of molecular entropy.
  5. Molecular Entropy Explanation
    This site give a comprehensive explanation of entropy, along with example reactions in which the entropy of the system is changing.

C2.3x Breaking Chemical Bonds
For molecules to react, they must collide with enough energy (activation energy) to break old chemical bonds before their atoms can be rearranged to form new substances.

  1. Activation Energy
    This is a shockwave animation with examples of the activation energy necessary to break old chemical bonds inorder to form new substances.
  2. Energy Diagrams - Activation Energy
    Move the slider along to see the breaking and forming of bonds and the energy changes including activation energy along the reaction path. Click the button to change the reaction example.
  3. IIT New
    Laboratory guidelines and set up for comparing endothermic and exothermic reactions. It also describes demonstrations for these two types of reactions.
  4. Visionlearning
    Outstanding! Great site to get animations of the breaking and forming of bonds in the formation of water from oxygen and hydrogen. This is found under chemical equations. This also shows the reaction between sodium and chlorine to form an ionic compound, as well as the change in atomic and ionic size. This is found under chemical bonds.

C2.4x Electron Movement
For each element, the arrangement of electrons surrounding the nucleus is unique. These electrons are found in different energy levels and can only move from a lower energy level (closer to nucleus) to a higher energy level (farther from nucleus) by absorbing energy in discrete packets. The energy content of the packets is directly proportional to the frequency of the radiation. These electron transitions will produce unique absorption spectra for each element. When the electron returns from an excited (high energy state) to a lower energy state, energy is emitted in only certain wavelengths of light, producing an emission spectra.

  1. Absorption Spectra
    Different elements create a series of bright lines at certain wavelengths. heating the atoms gives them some extra energy, so some of their electrons can jump up to higher energy levels. Then, when one of these electrons drops back down to a lower level, it emits a photon --at one of that element's special frequencies, of course.
  2. Absorption Spectra
    Outstanding This site has examples of absorption spectra from different elements.
  3. Bohr Model of the Atom Applet
    This applet explains the basic concepts behind Bohr's model of the atom, along with animation of the electrons being excited to higher energy levels before emitting radiation and falling back down.
  4. Energy Levels
    Lively applets animate Bohr's atom and lead to the modern idea of the energy level atom.
  5. How do I read an electron configuration table?
    An electron configuration table is a type of code that describes how many electrons are in each energy level of an atom and how the electrons are arranged within each energy level.
  6. How many electrons fit in each shell around an atom?
    The maximum number of electrons that can occupy a specific energy level can be found using the following formula: Electron Capacity = 2n2
  7. Jumping and Falling Electrons
    This site allows the students to excite an electron on an atom to see the resulting jump in energy levels and emission of electromagnetic radiation.
  8. Light Emission and Absorption Tutorial
    This interactive tutorial investigates flame tests, electron excitement, light emission from these excited atoms, and the relationship between electron movement and the bright line spectrum. A short quiz follows the tutorial.
  9. The Photoelectric Effect New
    See how light knocks electrons off a metal target, and recreate the experiment that spawned the field of quantum mechanics.

C2.5x Nuclear Stability
Nuclear stability is related to a decrease in potential energy when the nucleus forms from protons and neutrons. If the neutron/proton ratio is unstable, the element will undergo radioactive decay. The rate of decay is characteristic of each isotope; the time for half the parent nuclei to decay is called the half-life. Comparison of the parent/daughter nuclei can be used to determine the age of a sample. Heavier elements are formed from the fusion of lighter elements in the stars.

  1. Balancing Alpha Decay Nuclear Equations
    This site contains an applet that allows the student to fill in the blanks of a nuclear decay equation.
  2. Balancing Beta Decay Nuclear Equations
    This site contains an applet that allows the student to fill in the blanks of a nuclear decay equation.
  3. Basic Nuclear Fission    
    This site describes nuclear fission, has some great animations of nuclear fission, and students can test their knowledge with a short quiz at the end.  You can also select nuclear fusion on the left side to learn about it as well.
  4. Build a Carbon Atom
    This site allows students to make protons and neutrons using quarks, upload these subatomic particles to an atom, and see if the resulting atom is stable. It shows the students that an unequal number of protons and neutrons will lead to radioactive atoms.
  5. Calculating Protons, Neutrons, and Electrons of Ions, Isotopes, and Neutral Atoms
    This site has a nice table that takes a number of common elements and shows how the number of protons, neutrons and electrons determine if an element is neutral atom, or an Ion or Isotope.
  6. Halflife
    The halflife is the amount of time it takes for half of the atoms in a sample to decay. The halflife for a given isotope is always the same.
  7. Half-Life Online Experiment
    This site challenges students to determine the half-life of a radioisotope using data points collected and graphed.
  8. Ions, Isotopes and Electron Shells
    Normally, atoms contain equal numbers of protons and electrons. Because the positive and negative charges cancel each other out, atoms are normally electrically neutral. When the number of electrons changes in an atom, the electrical charge changes. This site explains the nature of Ions, and Isotopes.
  9. Isotopes of Pennies
    This site provides lessons for understanding radioactivity and isotopes using pennies to represent subatomic particles.
  10. Nuclear Chemistry and the Community
    Here you can take your students through a quick tour or choose the "2 day class" tour. The expected outcome is that students can apply nuclear science to world events and begin to critically evaluate what they see, hear, and read.
  11. Nuclear Fusion
    This site goes into detail about nuclear fusion, and it explains it very well.
  12. Nuclear Reactions Tutorial
    This site contains a tutorial teaching the students how to balance different types of nuclear reactions. A short quiz follows the tutorial.
  13. Nuclear Stability of Isotopes
    This site has an applet that allows the students to click on different isotopes, view their number of sub-atomic particles, and see if these isotopes are stable or unstable. Unstable isotopes will decay and the applet shows what stable isotopes they will decay into.
  14. Radioactive Decay
    This site has an Applet that demonstrates rates of radioactive decay. Shown (red dots) is a large number of identical atomic nuclei, each obeying the same decay law. Now select the half life time of the nuclei with the slider, press the strat button, and watch them decay away as a function of time.

 

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