Transcript BASIC_CHEMISTRY_v.2013 - San Jose Unified School District

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
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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
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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
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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
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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
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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)
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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
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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
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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.
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ATOMS AND MOLECULES
2
Protons
Nucleus
2
Neutrons
2
Electrons
Helium atom
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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.
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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.
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LAW OF CONSERVATION OF
MATTER
MATTER IS NEITHER CREATED NOR
DESTROYED
Even after a chemical reaction the amount of
matter remains constant.
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LAW OF CONSERVATION OF
ENERGY
ENERGY IS NEITHER CREATED NOR
DESTROYED
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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.
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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
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ENERGY LEVELS
(electron shells)
Outermost electron shell (can hold 8 electrons)
Electron
HYDROGEN (H)
Atomic number = 1
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First electron shell (can hold 2 electrons)
CARBON (C)
Atomic number = 6
NITROGEN (N)
Atomic number = 7
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OXYGEN (O)
Atomic number = 8
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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
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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).
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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
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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).
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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.
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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.
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IONIC BOND
+
Na
Cl
Na
Sodium atom
Cl
Chlorine atom
Na
Na+
Sodium ion
–
Cl
Cl–
Chloride ion
Sodium chloride (NaCl)
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IONIC BOND
•Sodium and chloride ions bond to form sodium
chloride, common table salt
Na+
Cl–
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BONDS IN H2O
Hydrogen bond
LIQUID WATER
Hydrogen bonds constantly
break and re-form
ICE
Hydrogen bonds are stable
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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,
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6H2O.
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STRUCTURAL FORMULAS
Show the number and kind of atoms in one molecule
of a compound
Shows how the atoms are attached to one another
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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.
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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).
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MIXTURES
Mixtures may be either:
HOMOGENOUS, where all substances are
evenly mixed, or
HETEROGENOUS, where concentrations vary
through out the mixture.
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3 KINDS OF MIXTURES
The three kinds of mixture are:
SOLUTION
SUSPENSION
COLLOID
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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.
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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.
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SOLUTION
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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.
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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.
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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
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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
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WATER
•In a water
molecule, oxygen
exerts a stronger
pull on the shared
electrons than
hydrogen
(–)
(–)
O
H
H
(+)
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(+)
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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
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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
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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
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Salt
crystal
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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
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H+
OH–
Acidic solution
Increasingly ACIDIC
(Higher concentration of
H+)
pH Scale
Neutral solution
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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
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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
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