• Chemistry, Texas Essential Knowledge and Skills (adopted 2017)  

    In Chemistry, students conduct laboratory and field investigations, use scientific practices during investigations, and make informed decisions using critical thinking and scientific problem solving. Students study a variety of topics that include characteristics of matter, use of the Periodic Table, development of atomic theory and chemical bonding, chemical stoichiometry, gas laws, solution chemistry, thermochemistry, and nuclear chemistry. Students will investigate how chemistry is an integral part of our daily lives.

    Scientific Processes

    (A) The student, for at least 40% of instructional time, conducts laboratory and field investigations using safe, environmentally appropriate, and ethical practices. 

    (B) The student uses scientific practices during laboratory and field investigations.

    (C)The student uses critical thinking, scientific reasoning, and problem solving to make informed decisions. 

     

    Science Concepts

    The student knows the characteristics of matter and can analyze the relationships between chemical and physical changes and properties. 

    The student is expected to:

    (A) differentiate between physical and chemical changes and properties;

    (B) identify extensive properties such as mass and volume and intensive properties such as density and melting point;

    (C) compare solids, liquids, and gases in terms of compressibility, structure, shape, and volume; and

    (D) classify matter as pure substances or mixtures through investigation of their properties.

     

    The student understands the historical development of the Periodic Table and can apply its predictive power. 

    The student is expected to:

    (A) explain the use of chemical and physical properties in the historical development of the Periodic Table;

    (B) identify and explain the properties of chemical families, including alkali metals, alkaline earth metals, halogens, noble gases, and transition metals, using the Periodic Table; and

    (C) interpret periodic trends, including atomic radius, electronegativity, and ionization energy, using the Periodic Table. 

    The student knows and understands the historical development of atomic theory. 

    The student is expected to:

    (A) describe the experimental design and conclusions used in the development of modern atomic theory, including Dalton's Postulates, Thomson's discovery of electron properties, Rutherford's nuclear atom, and Bohr's nuclear atom;

    (B) describe the mathematical relationships between energy, frequency, and wavelength of light using the electromagnetic spectrum;

    (C) calculate average atomic mass of an element using isotopic composition; and

    (D) express the arrangement of electrons in atoms of representative elements using electron configurations and Lewis valence electron dot structures.
     

    The student knows how atoms form ionic, covalent, and metallic bonds. 

    The student is expected to:

    (A) name ionic compounds containing main group or transition metals, covalent compounds, acids, and bases using International Union of Pure and Applied Chemistry (IUPAC) nomenclature rules;

    (B) write the chemical formulas of ionic compounds containing representative elements, transition metals and common polyatomic ions, covalent compounds, and acids and bases;

    (C) construct electron dot formulas to illustrate ionic and covalent bonds;

    (D) describe metallic bonding and explain metallic properties such as thermal and electrical conductivity, malleability, and ductility; and

    (E) classify molecular structure for molecules with linear, trigonal planar, and tetrahedral electron pair geometries as explained by Valence Shell Electron Pair Repulsion (VSEPR) theory.

    The student can quantify the changes that occur during chemical reactions. 

    The student is expected to:

    (A) define and use the concept of a mole;

    (B) calculate the number of atoms or molecules in a sample of material using Avogadro's number;

    (C) calculate percent composition of compounds;

    (D) differentiate between empirical and molecular formulas;

    (E) write and balance chemical equations using the law of conservation of mass;

    (F) differentiate among double replacement reactions, including acid-base reactions and precipitation reactions, and oxidation-reduction reactions such as synthesis, decomposition, single replacement, and combustion reactions;

    (G) perform stoichiometric calculations, including determination of mass and gas volume relationships between reactants and products and percent yield; and

    (H) describe the concept of limiting reactants in a balanced chemical equation.

    The student understands the principles of ideal gas behavior, kinetic molecular theory, and the conditions that influence the behavior of gases. 

    The student is expected to:

    (A) describe and calculate the relations between volume, pressure, number of moles, and temperature for an ideal gas as described by Boyle's law, Charles' law, Avogadro's law, Dalton's law of partial pressure, and the ideal gas law; and

    (B) describe the postulates of kinetic molecular theory.

    The student understands and can apply the factors that influence the behavior of solutions. 

    The student is expected to:

    (A) describe the unique role of water in solutions in terms of polarity;

    (B) apply the general rules regarding solubility through investigations with aqueous solutions;

    (C) calculate the concentration of solutions in units of molarity;

    (D) calculate the dilutions of solutions using molarity;

    (E) distinguish among types of solutions such as electrolytes and nonelectrolytes; unsaturated, saturated, and supersaturated solutions; and strong and weak acids and bases;

    (F) investigate factors that influence solid and gas solubilities and rates of dissolution such as temperature, agitation, and surface area;

    (G) define acids and bases and distinguish between Arrhenius and Bronsted-Lowry definitions and predict products in acid-base reactions that form water; and

    (H) define pH and calculate the pH of a solution using the hydrogen ion concentration.


    The student understands the energy changes that occur in chemical reactions. 

    The student is expected to:

    (A) describe energy and its forms, including kinetic, potential, chemical, and thermal energies;

    (B) describe the law of conservation of energy and the processes of heat transfer in terms of calorimetry;

    (C) classify reactions as exothermic or endothermic and represent energy changes that occur in chemical reactions using thermochemical equations or graphical analysis; and

    (D) perform calculations involving heat, mass, temperature change, and specific heat.
     

    The student understands the basic processes of nuclear chemistry. 

    The student is expected to:

    (A) describe the characteristics of alpha, beta, and gamma radioactive decay processes in terms of balanced nuclear equations; and

    (B) compare fission and fusion reactions.