California State Science Standards Grades 9-12 Chemistry Atomic and Molecular Structure 1. The periodic table displays the elements in increasing atomic number and shows how periodicity of the physical and chemical properties of the elements relates to atomic structure. As a basis for understanding this concept: S1(9-10)B3 a. Students know how to relate the position of an element in the periodic table to its atomic number and atomic mass. S1(9-10)B1.6 S1(9-10)B3.1 S1(9-10)B3.2 d. Students know how to use the periodic table to determine the number of electrons available for bonding. S1(9-10)B1.5 S1(9-10)B3.1 S1(9-10)B3.4 e. Students know the nucleus of the atom is much smaller than the atom yet contains most of its mass. S1(9-10)B1.1 S1(9-10)B1.4 3/22/2016 Bryan James Cowley M.A. 1 California State Science Standards Grades 9-12 Chemistry Chemical Bonds 2. Biological, chemical, and physical properties of matter result from the ability of atoms to form bonds from electrostatic forces between electrons and protons and between atoms and molecules. As a basis for understanding this concept: a. Students know atoms combine to form molecules by sharing electrons to form covalent or metallic bonds or by exchanging electrons to form ionic bonds. S1(9-10)B5.1 b. Students know chemical bonds between atoms in molecules such as H2 , CH4 , NH3 , H2CCH2, N2 , Cl2 , and many large biological molecules are covalent. S1(9-10)B5.1 S1(11-12)B3 S1(11-12)B4 Conservation of Matter and Stoichiometry 3. The conservation of atoms in chemical reactions leads to the principle of conservation of matter and the ability to calculate the mass of products and reactants. As a basis for understanding this concept: S1(9-10)B8 3/22/2016 Bryan James Cowley M.A. 2 California State Science Standards Grades 9-12 Chemistry Acids and Bases 5. Acids, bases, and salts are three classes of compounds that form ions in water solutions. As a basis for understanding this concept: S1(9-10)B5.6 d. Students know how to use the pH scale to characterize acid and base solutions. S1(9-10)B4.2 S6(9-10)B2.2 Solutions 6. Solutions are homogenous mixtures of two or more substances. As a basis for understanding this concept: S1(9-10)B4 a. Students know the definitions of solute and solvent. S1(9-10)B4 S1(9-10)B4.1 Chemical Thermodynamics 7. Energy is exchanged or transformed in all chemical reactions and physical changes of matter. As a basis for understanding this concept: b. Students know chemical processes can either release (exothermic) or absorb (endothermic) thermal energy. S1(9-10)B7.5 S1(9-10)B9.2 3/22/2016 Bryan James Cowley M.A. 3 California State Science Standards Grades 9-12 ChemistryReaction Rates 8. Chemical reaction rates depend on factors that influence the frequency of collision of reactant molecules. As a basis for understanding this concept: S1(9-10)B6.3 c. Students know the role a catalyst plays in increasing the reaction rate. S1(9-10)B6.6 Organic Chemistry and Biochemistry 10. The bonding characteristics of carbon allow the formation of many different organic molecules of varied sizes, shapes, and chemical properties and provide the biochemical basis of life. As a basis for understanding this concept: S1(9-10)B5.7 a. Students know large molecules (polymers), such as proteins, nucleic acids, and starch, are formed by repetitive combinations of simple subunits. S1(9-10)B5.7 S1(11-12)B3 b. Students know the bonding characteristics of carbon that result in the formation of a large variety of structures ranging from simple hydrocarbons to complex polymers and biological molecules. S1(9-10)B5.7 S1(11-12)B3 c. Students know amino acids are the building blocks of proteins. S1(9-10)B5.7 S1(11-12)B3 S2(9-10)B2.5 3/22/2016 Bryan James Cowley M.A. 4 SAN JOSE UNIFIED SCHOOL DISTRICT SCIENCE CONTENT STANDARD, BENCHMARKS, AND KNOWLEDGE SKILLS S1 THE STUDENT UNDERSTANDS AND APPLIES THE CONCEPTS OF PHYSICAL SCIENCE. S1(9-10)B1 Knows the structure of an atom S1(9-10)B1.1 Understands that the nucleus contains most of an atom’s mass (e.g., consisting of protons and neutrons; electrons have little mass but fill most of the space; atomic mass, atomic mass units, mass of electrons) S1(9-10)B1.2 Understands that in a neutrally charged atom, positive charges (protons) equal negative charges (electrons); an electrically charged ion is formed when an atom gains or loses negative charge S1(9-10)B1.3 Understands how electrical forces between the nucleus and electrons hold the atom together S1(9-10)B1.5 Understands how the spatial arrangement and energy of electrons in an atom determines the chemical properties of the atom S1(9-10)B1.6 Understands how isotopes of an element vary S1(9-10)B2 Understands how the properties of solids, liquids and gases are determined by the forces between their particles and the amount of energy these particles possess S1(9-10)B2.1 Understands that due to their kinetic energy, particles (atoms, molecules, ions) of matter are in constant, random motion; the higher the temperature, the faster they move. S1(9-10)B2.2 Understands that inter-molecular forces between particles are weaker in liquids than in solids; there are no inter-molecular forces between particles of a gas S1(9-10)B2.4 Understands how the random motion of particles explains diffusion of particles from an area of higher concentration to an area of lower concentration 3/22/2016 Bryan James Cowley M.A. 5 SAN JOSE UNIFIED SCHOOL DISTRICT SCIENCE CONTENT STANDARD, BENCHMARKS, AND KNOWLEDGE SKILLS S1 THE STUDENT UNDERSTANDS AND APPLIES THE CONCEPTS OF PHYSICAL SCIENCE. S1(9-10)B3 Understands how elements are arranged in the periodic table with repeating patterns among elements with similar properties S1(9-10)B3.1 Understands how information about an element can be determined from the Periodic Table (e.g., atomic number, atomic mass, number of electrons or neutrons) S1(9-10)B3.2 Understands periodicity and how the position of an element in the Periodic Table relates to its atomic number and atomic mass. S1(9-10)B3.3 Understands how the Periodic Table can be used to identify the physical properties of elements (e.g., metal, non-metals, metalloids, solids, gases, halogens, alkali, alkaline earth metals) S1(9-10)B3.4 Understands how the Periodic Table can be used to identify the chemical properties of elements (e.g., acidforming, base-forming, number of electrons in outermost energy levels, reactivity with other elements in the table) S1(9-10)B4 Understands that solutions are homogeneous mixtures of two or more substances. S1(9-10)B4.1 Understands how the dissolving process results from the random motion of solute particles among particles of solvent (e.g., solid/liquid, liquid/liquid, gas/liquid) S1(9-10)B5 Understands that the chemical and physical properties of matter result from the ability of atoms to form bonds, creating many different kinds of compounds S1(9-10)B5.1 Understands how two or more atoms combine to form molecules by sharing electrons to form covalent or metallic bonds, or by exchanging electrons to form ionic bonds. S1(9-10)B5.2 Understands chemical symbols, simple formulas and nomenclature that represent atoms, molecules and compounds (e.g., Lewis dot, Na+, C6H12O6, NH4+, symbols for isotopes, sodium chloride) S1(9-10)B5.6 Understands that acids, bases and salts are three classes of compounds that form ions in water solution (e.g., hydrogen ion donating/accepting ions, strong/weak acids and bases, pH scale characterizes acid/base solutions) S1(9-10)B5.7 Understands that carbon compounds formulate the biochemical basis of life on earth (e.g., hydrocarbons, carbohydrates, fats, amino acids, proteins, nucleic acids) 3/22/2016 Bryan James Cowley M.A. 6 SAN JOSE UNIFIED SCHOOL DISTRICT SCIENCE CONTENT STANDARD, BENCHMARKS, AND KNOWLEDGE SKILLS S1 THE STUDENT UNDERSTANDS AND APPLIES THE CONCEPTS OF PHYSICAL SCIENCE. S1(9-10)B6 Understands that chemical reactions can take place at different rates and depend on a variety of factors S1(9-10)B6.1 Understands chemical reactions (e.g., reactants, products, representation by chemical equation) S1(9-10)B6.4 Understands how adding heat or light (endothermic) to reactants increases their kinetic energy and rate at which reactant molecules collide. S1(9-10)B6.6 Understands the role of a catalyst/enzyme in increasing the rate of a chemical/biochemical reaction S1(9-10)B7 Understands different types of chemical reactions and their roles in physical and biological processes S1(9-10)B7.1 Understands that in a synthesis reaction, two or more substances combine to form a new compound (e.g., A+X-->AX; C+O2-->CO2 ; formation of acid rain; protein synthesis) S1(9-10)B7.2 Understands that in a decomposition reaction, a single compound produces two new compounds (e.g., AX--> A+X; 2H2O--> 2H2 + O2 ; decomposition of glucose during cellular respiration, biological decay; electrolysis of water) S1(9-10)B7.3 Understands that in a single replacement reaction, one element replaces another similar element from a compound (e.g., A+BX--> AX+B; Y+BX-->BY+X; Mg + 2HCl-->H2 + MgCl2 ; oxygen uptake by hemoglobin) S1(9-10)B7.5 Understands that endothermic reactions require energy; exothermic reactions release energy S1(9-10)B8 Understands that matter is conserved during a chemical reaction S1(9-10)B9 another Understands that energy can be neither created nor destroyed, but can be converted from one form to 3/22/2016 Bryan James Cowley M.A. 7 ATOMS AND MOLECULES In 1805 English chemist John Dalton presented evidence that matter is made of tiny particles called atoms In 1897 3 types of subatomic particle were discovered 3/22/2016 Bryan James Cowley M.A. 8 ATOMS AND MOLECULES The PROTON is positively charged • Comprises one half of the nucleus • Atoms of every element have at one least proton The NEUTRON has a neutral electrical charge • The other half of the atom’s nucleus The ELECTRON is a negatively charged • Particle that rapidly orbits an atom’s nucleus An atom’s charge (+ or -) is determined by whether it has more protons or electrons. When two or more atoms (from either the same or different elements) bond a MOLECULE is formed. 3/22/2016 Bryan James Cowley M.A. 9 ATOMS AND MOLECULES 2 Protons Nucleus 2 Neutrons 2 Electrons Helium atom 3/22/2016 Bryan James Cowley M.A. 10 MATTER Matter has mass and takes up space. Matter exists in 3 “states” on earth. SOLID has definite shape and volume. LIQUID definite volume, not definite shape. GAS has neither definite shape nor volume. PLASMA is a 4th state found only in the hottest stars. 3/22/2016 Bryan James Cowley M.A. 11 PROPERTIES OF MATTER PHYSICAL properties (e.g. color, boiling point, hardness) CHEMICAL properties (e.g. it’s ability to interact with other matter) Matter undergoes physical change when it changes state. A chemical change, or reaction, alters the matter composition. 3/22/2016 Bryan James Cowley M.A. 12 LAW OF CONSERVATION OF MATTER MATTER IS NEITHER CREATED NOR DESTROYED Even after a chemical reaction the amount of matter remains constant. 3/22/2016 Bryan James Cowley M.A. 13 LAW OF CONSERVATION OF ENERGY ENERGY IS NEITHER CREATED NOR DESTROYED 3/22/2016 Bryan James Cowley M.A. 14 ENERGY LEVELS (electron shells) Electrons orbit the atom nucleus at various ENERGY LEVELS Some atoms may have up to eight energy levels. The level closest to the nucleus has the least energy. The further the level is from the nucleus the more energy it has. 3/22/2016 Bryan James Cowley M.A. 15 ENERGY LEVELS (electron shells) When the maximum number of the electrons occupy the outer level that atom is said to be STABLE and unreactive The outermost energy level determines the chemical properties of an atom In most atoms, a full outer level holds eight electrons 3/22/2016 Bryan James Cowley M.A. 16 ENERGY LEVELS (electron shells) Outermost electron shell (can hold 8 electrons) Electron HYDROGEN (H) Atomic number = 1 3/22/2016 First electron shell (can hold 2 electrons) CARBON (C) Atomic number = 6 NITROGEN (N) Atomic number = 7 Bryan James Cowley M.A. OXYGEN (O) Atomic number = 8 17 ELEMENTS An ELEMENT is the matter comprised of only one type of atom element is a substance that cannot be broken down to other substances by ordinary chemical means There are 94 naturally occurring elements 3/22/2016 Bryan James Cowley M.A. 18 ELEMENTS Every element has one or two letter abbreviation based on the first one or two letters in it's name. For example, H stands for the English word Hydrogen, W stands for the German word Wolfram (Tungsten), Ag stands for the Latin word Argentum (Silver). 3/22/2016 Bryan James Cowley M.A. 19 ATOMIC MASS & NUMBER An element's ATOMIC NUMBER is the number of protons in it's nucleus. This number never varies An element's ATOMIC MASS is equal to the sum of protons and neutrons in it's nucleus. Since the number of neutrons in an element's nucleus does vary so does it's mass 3/22/2016 Bryan James Cowley M.A. 20 ISOTOPE An element with more or less than the standard number of neutrons is called an ISOTOPE. Isotopes names list the number of the neutrons after the element name (i.e. Carbon-14). 3/22/2016 Bryan James Cowley M.A. 21 COMPOUNDS An atom whose outer energy level is not filled may share or transfer electrons with another atom and form a CHEMICAL BOND When two or more atoms from different elements bond a COMPOUND is formed. 3/22/2016 Bryan James Cowley M.A. 22 CHEMICAL BONDS There are two types of chemical bonds. COVALENT BONDS result when two or more atoms share electrons. If only two atoms are bonded this way they form a diatomic molecule. IONIC BONDS result when an atom accepts or donates an electron to another atom. The atom that gains an electron becomes positively charged while the atom that looses an electron becomes negatively charged. These electrically charged atoms are called IONS. 3/22/2016 Bryan James Cowley M.A. 23 IONIC BOND + Na Cl Na Sodium atom Cl Chlorine atom Na Na+ Sodium ion – Cl Cl– Chloride ion Sodium chloride (NaCl) 3/22/2016 Bryan James Cowley M.A. 24 IONIC BOND •Sodium and chloride ions bond to form sodium chloride, common table salt Na+ Cl– 3/22/2016 Bryan James Cowley M.A. 25 BONDS IN H2O Hydrogen bond LIQUID WATER Hydrogen bonds constantly break and re-form ICE Hydrogen bonds are stable 3/22/2016 Bryan James Cowley M.A. 26 3/22/2016 Bryan James Cowley M.A. 27 UNDERSTANDING NOTATION Chemical formulas show the elements that make up a compound, 6H2O The number of atoms is expressed as subscript, 6H2O. The number of molecules is a coefficient that precedes the formula, 3/22/2016 6H2O. Bryan James Cowley M.A. 28 STRUCTURAL FORMULAS Show the number and kind of atoms in one molecule of a compound Shows how the atoms are attached to one another 3/22/2016 Bryan James Cowley M.A. 29 CARBON SKELETONS Ethane Propane Carbon skeletons vary in length. Butane Isobutane Skeletons may be unbranched or branched. 1-Butene 2-Butene Skeletons may have double bonds, which can vary in location. Cyclohexane Benzene Skeletons may be arranged in rings. 3/22/2016 Bryan James Cowley M.A. 30 MIXTURES Matter is either classified as a pure substance (one kind of element or compound) or a mixture (two or more pure substances). In a mixture each pure substance retains it's own chemical identity. Each pure substance in the mixture can be physically separated (i.e. filtration or evaporation). 3/22/2016 Bryan James Cowley M.A. 31 MIXTURES Mixtures may be either: HOMOGENOUS, where all substances are evenly mixed, or HETEROGENOUS, where concentrations vary through out the mixture. 3/22/2016 Bryan James Cowley M.A. 32 3 KINDS OF MIXTURES The three kinds of mixture are: SOLUTION SUSPENSION COLLOID 3/22/2016 Bryan James Cowley M.A. 33 SOLUTION SOLUTION is a homogenous mixture where one substance dissolves in another. SOLUTE is the substance that dissolves. SOLVENT is the substance that does the dissolving. 3/22/2016 Bryan James Cowley M.A. 34 SOLUTION Solutions are the "best mixed" mixture. A solution is SATURATED when no more solute will dissolve. DISSOCIATION is the process where ionic compounds separate into individual ions which enter the solution. 3/22/2016 Bryan James Cowley M.A. 35 SOLUTION 3/22/2016 Bryan James Cowley M.A. 36 SUSPENSION A SUSPENSION is a heterogeneous mixture whose substances do not mix completely. Most substances "settle out” of the mixture. Those that do not settle are suspended giving the mixture a cloudy appearance. 3/22/2016 Bryan James Cowley M.A. 37 COLLOID A homogenous mixture whose particles are larger than those in a solution but smaller than those in a suspension. Colloidal particles may be groups of atoms, ions, molecules or even a single giant molecule. Examples include, cytoplasm, gelatin and homogenized milk. 3/22/2016 Bryan James Cowley M.A. 38 WATER •Atoms in a covalently bonded molecule may share electrons equally, creating a nonpolar molecule •If electrons are shared unequally, a polar molecule is created •Water is polar 3/22/2016 Bryan James Cowley M.A. 39 WATER –This makes the oxygen end of the molecule slightly negatively charged –The hydrogen end of the molecule is slightly positively charged –Water is therefore a polar molecule 3/22/2016 Bryan James Cowley M.A. 40 WATER •In a water molecule, oxygen exerts a stronger pull on the shared electrons than hydrogen (–) (–) O H H (+) 3/22/2016 Bryan James Cowley M.A. (+) 41 Water’s polarity leads to hydrogen bonding and other unusual properties •The charged regions on water molecules are attracted to the oppositely charged regions on nearby molecules Hydrogen bond –This attraction forms weak bonds called hydrogen bonds 3/22/2016 Bryan James Cowley M.A. 42 Hydrogen bonds make liquid water cohesive •Due to hydrogen bonding, water molecules can move from a plant’s roots to its leaves •Insects can walk on water due to surface tension created by cohesive water molecules 3/22/2016 Bryan James Cowley M.A. 43 WATER IS A VERSATILE SOLVENT •Solutes whose charges or polarity allow them to stick to water molecules dissolve in water Na+ Na+ Cl– Cl– –They form aqueous solutions Ions in solution 3/22/2016 Bryan James Cowley M.A. Salt crystal 44 ACIDS AND BASES •A compound that releases H+ ions in solution is an acid, and one that accepts H+ ions in solution is a base •Acidity is measured on the pH scale: –0-7 is acidic –8-14 is basic –Pure water and solutions that are neither basic nor acidic are neutral, with a pH of 7 3/22/2016 Bryan James Cowley M.A. 45 H+ OH– Acidic solution Increasingly ACIDIC (Higher concentration of H+) pH Scale Neutral solution 3/22/2016 Increasingly BASIC (Lower concentration of H+) NEUTRAL [H+] = [OH–] Basic solution Bryan James Cowley M.A. Lemon juice; gastric juice Grapefruit juice Tomato juice Urine PURE WATER Human blood Seawater Milk of magnesia Household ammonia Household bleach Oven cleaner 46 pH and cells •Cells are kept close to pH 7 by buffers •Buffers are substances that resist pH change –They accept H+ ions when they are in excess and donate H+ ions when they are depleted –Buffers are not foolproof 3/22/2016 Bryan James Cowley M.A. 47