Chemistry Pre-Requisite Standards
Standard 10

Domain

Chemistry Pro-Core Standard

Related Prior Grade Standards

All language for Ohio’s Learning Standards in Science. Only the relevant sections of the standard and Content Elaborations are referenced.

Structure and Properties of Matter

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Atomic structure

  • Evolution of atomic models/theory
  • Electrons
  • Electron configurations

6.PS.1: Matter is made of atoms, which are particles that are too small to be seen, even with a light microscope.

PS.M.2: Over time, technology was introduced that allowed the atom to be studied in more detail. The atom is composed of protons, neutrons and electrons that have measurable properties, including mass and, in the case of protons and electrons, a characteristic charge. An atom is empty space with a very small positively charged nucleus. The nucleus is composed of protons and neutrons. The electrons move about in the empty space that surrounds the nucleus. Although current understanding goes beyond the Bohr Model, it can still be used to represent the atom and develop the idea of valence electrons.

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Periodic Table

  • Properties
  • Trends

6.PS.1: An element is a chemical substance that cannot be broken down into simpler substances. There are approximately 90 different naturally occurring elements that have been identified. There are additional elements that were made in a laboratory, but these elements are not stable. All atoms of any one element are alike but are different from atoms of other elements.

7.PS.1: All substances are composed of one or more elements. Elements are organized into groups based on their properties (including melting and/or boiling points). Elements with similar properties are grouped together on the periodic table. These groups include metals, non-metals and metalloids. Most metals are malleable, have high melting points, are usually solid at room temperature and are good conductors of heat and electricity. Nonmetals are poor conductors of heat and electricity and tend to be dull and brittle in the solid state. Depending on the element, they may be solid, liquid or gas at room temperature. Metalloids demonstrate some properties of both metals and non-metals.

PS.M.3: The periodic table was arranged so that elements with similar chemical and physical properties are in the same group or family. When elements are listed in order of increasing atomic number, the same sequence of properties appears over and over again; this is the periodic law. Trends in simple observable properties, like density or melting point, can be examined within families or groups on the periodic table. These trends allow scientists to make predictions about new elements. Metalloids are elements that have some properties of metals and some properties of nonmetals. Metals, nonmetals, metalloids, periods and groups or families including the alkali metals, alkaline earth metals, halogens and noble gases can be identified by their position on the periodic table. Elements in Groups 1, 2 and 17 have characteristic ionic charges that will be used in this course to predict the formulas of compounds.

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Chemical bonding

  • Ionic
  • Polar/covalent

6.PS.1: Molecules are the combination of two or more atoms that are joined together chemically.

7.PS.2: Compounds are composed of two or more different elements joined together chemically. Each compound has its own unique composition of type and number of elements and atoms.

Molecules are the combination of two or more atoms that are joined together chemically. Molecules can be either elements or compounds (e.g., elemental hydrogen is a molecule containing two atoms of hydrogen; water is a molecule containing two atoms of hydrogen joined with one atom of oxygen).

All particles of a pure substance have nearly identical mass. Particles of different substances usually have different masses, depending on their composition. Each element and compound has properties, some of which are independent of the amount of the sample.

PS.M.4: Atoms may be bonded together by losing, gaining or sharing valence electrons to form molecules or three- dimensional lattices. An ionic bond involves the attraction of two oppositely charged ions, typically a metal cation and a nonmetal anion formed by transferring electrons between the atoms. An ion attracts oppositely charged ions from every direction, resulting in the formation of a three-dimensional lattice. Covalent bonds result from the sharing of electrons between two atoms, usually nonmetals. Covalent bonding can result in the formation of structures ranging from small individual molecules to three-dimensional lattices (e.g., diamond). The bonds in most compounds fall on a continuum between the two extreme models of bonding: ionic and covalent.

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Representing compounds

  • Formula writing
  • Nomenclature
  • Models and shapes (Lewis structures, ball and stick, molecular geometries)

6.PS.1: Molecules are the combination of two or more atoms that are joined together chemically.

7.PS.2: Molecules are the combination of two or more atoms that are joined together chemically. Molecules can be either elements or compounds (e.g., elemental hydrogen is a molecule containing two atoms of hydrogen; water is a molecule containing two atoms of hydrogen joined with one atom of oxygen).

PS.M.4: Using the periodic table to determine ionic charge, formulas of ionic compounds containing elements from groups 1, 2, 17, hydrogen and oxygen can be predicted. Given a chemical formula, a compound can be named using conventional systems that include Greek prefixes where appropriate. Prefixes will be limited to represent values from one to 10. Given the name of an ionic or covalent substance, formulas can be written. Naming organic molecules is beyond this grade level and is reserved for an advanced chemistry course. Prediction of bond types from electronegativity values, polar covalent bonds, and writing formulas/naming compounds that contain polyatomic ions or transition metals are reserved for Chemistry.

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Quantifying matter

6.PS.1: Matter has properties of mass and volume. Mass measures the amount of matter in an object (e.g., a wood block) or substance (e.g., water), and volume measures the three-dimensional space that matter occupies. Mass can be measured with a balance. The volume of solids can be determined by water displacement or calculated from the dimensions of a regular solid.

Equal volumes of different substances usually have different masses. Some materials, like lead or gold, have a lot of mass in a relatively small space. Other materials, like packing peanuts and air, have a small mass in a relatively large amount of space. This concept of comparing substances by the amount of mass the substance has in a given volume is known as density. While the mass and volume of a material can change depending upon how much of the material there is, the density generally remains constant, no matter how much of the material is present. Therefore, density can be used to identify a material.

7.PS.2: All particles of a pure substance have nearly identical mass. Particles of different substances usually have different masses, depending on their composition.

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Intermolecular forces of attraction

  • Types and strengths
  • Implications for properties of substances
    • Melting and boiling point
    • Solubility
    • Vapor pressure

6.PS.2: Temperature is a measure of the average motion of the particles in a substance.

Solids, liquids and gases vary in the motion, spacing and attractions between particles. Solid particles are close together and held more rigidly in a space by the attractions between the particles. However, solid particles can still vibrate back and forth within this space. Liquid particles may be slightly farther apart but move with more speed than solid particles. In liquids, particles can move from one side of the sample to another. Gas particles are much farther apart and move with greater speed than liquid or solid particles. Because of the large spaces between the particles, gases are easily compressed into smaller volumes by pushing the particles closer together. Most substances can exist as a solid, liquid or gas depending on temperature. Generally, for a specific temperature, materials that exist as solids have the greatest attraction between the particles. Substances that exist as gases generally have the weakest attraction between the particles.

7.ESS.1: … water transfers from the hydrosphere to the atmosphere when evaporation occurs.

7.PS.2. Mixtures are materials composed of two or more substances that retain their separate compositions, even when mixed (e.g., water and sugar can be mixed together thoroughly at the molecular level but the water particles and sugar particles remain separate). When a solid substance dissolves in water, the particles of the solid separate and move freely with the water particles.

PS.M.1: Solutions are homogeneous mixtures of a solute dissolved in a solvent. The amount of a solid solute that can dissolve in a solvent generally increases as the temperature increases since the particles have more kinetic energy to overcome the attractive forces between them.

When heating a substance, a phase change will occur when the kinetic energy of the particles is great enough to overcome the attractive forces between the particles; the substance then melts or boils. Conversely, when cooling a substance, a phase change will occur when the kinetic energy of the particles is no longer great enough to overcome the attractive forces between the particles; the substance then condenses or freezes.

Interactions of Matter

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Chemical reactions

  • Types of reactions
  • Kinetics
  • Energy
  • Equilibrium
  • Acids/bases

7.PS.2: Matter can be separated or changed, but in a closed system, the number and types of atoms remains constant. For any change in a closed system, the number and type of atoms stay the same, even if the atoms are rearranged. Therefore, the mass remains constant. Mass is always conserved in a closed system … The conservation of matter can be demonstrated using simple balanced equations with their chemical formulas or pictorial representations of the reactants and products. The equations for photosynthesis and cellular respiration can be used to demonstrate this concept.

Energy input is required to break a molecule apart. When the separated atoms form new molecules, the output energy can be greater than or less than the original input energy.

7.PS.4: Chemical potential energy is associated with the position and arrangement of the atoms within substances. Rearranging atoms into new positions to form new substances (chemical reaction) is evidence that the chemical potential energy has most likely changed. The energy transferred when a chemical system undergoes a reaction is often thermal energy.

PS.M.1: Aqueous solutions can be classified as acidic (below 7 on the pH scale), neutral (7 on the pH scale), or basic (above 7 on the pH scale) …

PS.M.5: … conservation of matter is expressed by writing balanced chemical equations … reactants and products can be identified from an equation and simple equations can be written and balanced given either the formulas of the reactants and products or a word description of the reaction. Stoichiometric relationships beyond the coefficients in a balanced equation … are reserved for Chemistry.

During chemical reactions, thermal energy is either transferred from the system to the surroundings (exothermic) or transferred from the surroundings to the system (endothermic). Since the environment surrounding the system can be large, temperature changes in the surroundings may not be detectable.

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Gas laws

  • Pressure, volume and temperature
  • Ideal gas law

6.PS.1: … volume measures the three-dimensional space that matter occupies.

6.PS.2: Temperature is a measure of the average motion of the particles in a substance.

Gas particles are much farther apart (than solid or liquid particles) … Because of the large spaces between the particles, gases are easily compressed into smaller volumes by pushing the particles closer together.

PS.M.1: Generally, solids have greater density than liquids, which have greater density than gases due to the spacing between the particles. The density of a substance can be calculated from the slope of a mass vs. volume graph. Differences in densities can be determined by interpreting mass vs. volume graphs of the substances. Students should be able to calculate mass, volume or density, given two of the three values.

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Stoichiometry

  • Molecular calculations
  • Solutions
  • Limiting reagents

7.PS.2: All particles of a pure substance have nearly identical mass. Particles of different substances usually have different masses, depending on their composition. For any change in a closed system, the number and type of atoms stay the same, even if the atoms are rearranged.

PS.M.5: Stoichiometric relationships beyond the coefficients in a balanced equation … are reserved for Chemistry.