Ohio Resource Center

Chemistry: Understanding the Interactions of Matter

Course Overview

This course (designed for grade 11 or 12) builds on the content learned in Introduction to Chemistry and further develops students’ understanding of the unifying concepts of chemistry that are essential to understanding the interactions of matter and the impact of human activity on the natural world.

Within the course, there are seven main quests from which to develop standards-based learning cycle lessons:

  • Quest 1: Matter and Energy
  • Quest 2: Atoms
  • Quest 3: Compounds
  • Quest 4: Measuring Matter
  • Quest 5: Chemical Reactions
  • Quest 6: Behavior of Gases
  • Quest 7: Nuclear Chemistry

Here is an overview of each quest, listing some of the key concepts that should be addressed.

Quest 1: Matter and Energy

  • Pure substances exists as atoms, elements, or compounds. A pure substance has the same composition throughout. These substances can be found in either the solid, liquid, or gas phase. The phases of matter appear and behave differently from each other. Conversion of a particular kind of matter from one phase to another involves an energy change.
  • The kinetic theory of matter can be used to explain the behavior of solids, liquids, and gases. The kinetic theory of matter states that all matter is made of particles, that these particles are in constant motion, and that the total kinetic energy of particles remains constant. The particle motion in solids is much less than that of gases, with liquids having an intermediate level of particle motion between the other two states.

Examples of an Essential Question for Investigation:

Why is brine used on roadways during the winter?

Quest 2: Atoms

  • Our modern theory of atomic structure has been formed over hundreds of years and is based on the contributions of many scientists. The basis of our modern view of atomic structure comes from quantum mechanics. It is widely accepted that and atom consists of a small, dense, positive nucleus surrounded by a relatively large and relatively empty negative electron cloud. The negative electrons are held around the positive nucleus by electrostatic attraction. Each electron has a predictable amount of energy that corresponds to the energy level (distance away from the nucleus) in which the electron is found. We can give a general relative placement of electrons in an atom by writing their electron configuration. The most stable electron configuration for an atom represents its ground state.
  • Each atom has a particular number of valence electrons, or outer-energy-level electrons. The periodic table is arranged so that the atoms of each family (vertical column) have the same number of valence electrons. They also have similar properties. Elements are arranged in order of atomic number. Many other patterns are present in the periodic table and can be used to predict the properties of atoms. For example, as you move down a group (family), atoms become larger and their respective ionization energies decrease. As you move across series (period), atoms become smaller and their ionization energies increase.

Quest 3: Compounds

  • Compounds are formed from atoms bonded together by either ionic or covalent bonds. Ionic bonds are formed by the transfer of electrons, and covalent bonds are formed by the sharing of electrons. Compounds formed by ionic bonds are usually found in the solid phase at room temperature. They are typically hard and brittle, with high melting points and poor electrical and thermal conductivity. Compounds formed from covalently bonded atoms are fairly soft, with poor electrical and thermal conductivity. The properties of covalently bonded compounds are often affected by intermolecular forces, or forces between the molecules. Intermolecular forces include London dispersion, dipole–dipole attractions, Hydrogen bonding, and ion–dipole attractions. These intermolecular forces impact the behavior of the compound.
  • Compounds are represented by chemical formulas. There are three different types of chemical formulas: the empirical formula (represents the types of atoms in a compound in their smallest whole-number ratio), the molecular formula (represents the exact kind and number of atoms in a compound), and the structural formula (represents the structure of molecules by showing which atoms are bonded to which).
  • Polyatomic ions are atoms that are joined by covalent bonds but that have a net positive or negative charge.
  • Organic compounds are compounds that contain carbon and hydrogen. Carbon compounds can be small or large; arranged in chains, branched, or rings; and have single, double, or triple bonds.
  • Polymers are molecular substances with a high molecular mass that are formed from many repeating units called monomers.

Example of an Essential Questions for Investigation:

What is the difference between regular gasoline and ethanol fuel?

Quest 4: Measuring Matter

  • The mole is a counting unit in chemistry. It is used to represent the amount of matter that contains Avogadro’s number (6.02 x 1023) of atoms, molecules, or ions. The mass of one mole of an element is represented on the periodic table. The mass of each atom in a compound can be added to find the mass of the compound. The mass of each individual element in a compound contributes to the total mass and then can be used to calculate the percent composition of a compound.
  • The coefficients in a balanced chemical equation represent how many moles of each substance are present in a reaction, and can be used to determine the ration of reactant to product. The study of the amounts of compounds in reactions is stoichiometry.
  • Molarity represents the concentration of a solution in units of moles of solute/liter of solution.
  • Acids contain hydrogen, but not all substances that contain hydrogen are acids. Acids donate protons (or H+ ions) in reactions. Therefore, when acids are dissolved in water, they increase the hydronium ion (H3O+) concentration of the formed solutions.
  • Bases produce hydroxide (OH-) ions when dissolved in water. They often have OH- groups in their chemical formula, but not always. They also are described as proton acceptors.

Example of an Essential Question for Investigation:

What's the difference between 14K and 24K gold?

Quest 5: Chemical Reactions

  • Chemical equations are used to represent chemical reactions. Reactants are listed on the left followed by an arrow (which means "yields"), and products are listed on the right. In accordance with the law of conservation of mass, chemical equations must be balanced so that the number of atoms for each element in the equation is the same in the reactants and the products.
  • There are many different types of chemical reactions. Some more common ones include combustion of hydrocarbons, combination, decomposition, metathesis, replacement, and acid–base and reduction–oxidation reactions.
  • A given reaction will occur in a specific amount of time, called the rate of the reaction. Reaction rates are affected by the concentration of reactants, the temperature, the presence of a catalyst, and the surface area of the reactants or catalysts.
  • Some reactions reach equilibrium, the point when forward and reverse reactions are occurring at equal rates.

Example of an Essential Question for Investigation:

What is acid rain? Where does it come from?

Quest 6: Behavior of Gases

  • Theoretically ideal or perfect gases are used to approximate the behavior of real gases. Many different laws and equations can be used to describe the behavior of ideal gases quantitatively. One of the most widely know equations is PV = nRT, or the ideal gas equation. Other gas laws include Boyle’s law, Charles’ law, Dalton’s law of partial pressures, and Graham’s law of effusion.

Example of an Essential Question for Investigation:

Why does my soda fizz when I take the cap off?

Quest 7: Nuclear Chemistry

  • When the nucleus of an atom is unstable and emits radiation, it is in the process of radioactive decay. That radiation may be in the form of an alpha particle, a beta particle, or a gamma ray.
  • Radioactive isotopes are used in medicine during testing, for treating cancer, and for many other purposes.
  • Foods are irradiated in order to kill pathogens, to make the food safe for consumption.
  • Nuclear energy is converted into electrical energy in nuclear reactors, where radioactive substances decay and give off energy in the process.

Example of an Essential Question for Investigation:

Why are foods treated with radiation? Why is this controversial?