Chemistry Regents Review Notes
Safety, Scientific Method, and Graphing
Safety Precautions:
- Tie back long hair.
- Rinse arm if a liquid is spilled, then tell the teacher.
- Dispose of chemicals properly after an experiment.
Scientific Method:
- All variables must remain the same except the one being tested.
Graphing:
- Use an even scale of numbers and circle final points.
Unit 1: Atomic Structure
- Atoms contain subatomic particles (protons, neutrons, electrons).
- Protons:
- Have a +1 charge.
- Neutrons:
- Have a 0 charge.
- Mass of Neutron = 1 amu = Mass of Proton
- Electrons:
- Have a charge of -1 and a mass of 0.
- Charge Comparison:
- Electron charge is -1, proton charge is +1 (same magnitude, opposite charge).
- Table O:
- Shows symbols, mass, and charges of particles (electrons are represented as beta).
- Location of Protons and Neutrons:
- Located in the nucleus of an atom.
- Charge of Nucleus:
- Charge of an atom’s nucleus = (+) number of protons.
- Structure of Atoms:
- Atoms have a positively charged nucleus and negatively charged electrons located in “clouds” (orbitals) around the nucleus.
- Mass Number:
- Mass \ number = #protons + #neutrons
- Atomic Number:
- Atomic number = number of protons (All atoms of the same element have the same atomic number).
- Number of Neutrons:
- Isotopes:
- Atoms with the same number of protons, different number of neutrons (different mass number).
- Isotope Notation:
- Top number of isotope notation is Mass number and bottom number is atomic number.
- Other Notations:
- (C-14 or Carbon-14) Number after an element represents mass number.
- Atomic Mass:
- The weighted average of all the naturally occurring isotopes for that element.
- Average Atomic Mass Calculation:
- Abundance:
- Whatever whole number the atomic mass is closest to on the Periodic Table means that isotope is most abundant.
- Rutherford’s Gold Foil Experiment:
- Shows an atom is mostly empty space with a small, dense, positively charged nucleus.
- Thomson and Bohr’s Models:
- Showed electrons present in an atom.
- Wave-Mechanical Model (Electron Cloud Model):
- An orbital (cloud) is the most probable location of electrons.
- Neutral Atom:
- An Atom has the same number of protons and electrons as long as there is no charge (total charge of 0).
- Total (Net) Charge of an Atom:
- Total \ (Net) \ Charge \ of \ an \ atom = # \ protons - # \ electrons
- Ion:
- A charged element (it has lost or gained electrons): electron configuration will change if it is an ion (possible charges are found on PT).
Electron Configuration and Energy Levels
- Electron Configuration:
- Shows location of electron in their shells. Example: 2-8-2 (2 electrons in first energy level, 8 electrons in second energy level, 2 electrons in third energy level) CAN BE FOUND ON PERIODIC TABLE
- Energy Levels:
- First shell has less energy than 2nd shell.
- Electron Capacity:
- First shell can have a max of 2 electrons and Second shell can have a max of 8 electrons.
- Valence Electrons:
- Electrons found in the outer most shell (last number in electron configuration).
- Lewis Dot Diagram:
- For a single atom just shows the valence electrons (electrons represented by dots, drawn in pairs).
- Excited Electrons:
- When excited electron (at higher energy level) moves to ground state (lower energy level), a specific amount of energy is emitted (sometimes as light/bright line spectrum)
- Excited Electron Configuration:
- Is not the same as the configuration on the reference table (there will be one less electron in one energy level and one more electron in another energy level).
- Energy Emission:
- Energy emitted from excited electron can be used to determine identity of element
- Bright Line Spectrum:
- When viewing a Bright line spectrum- elements must line up exactly to be part of the mixture in the spectrum
Unit 2: Nuclear Chemistry
- Table O:
- Shows a positron and beta particles have same mass (0) & opposite charge (Beta negative, positron positive).
- Particle Penetration:
- Beta particle has less mass and greater penetrating power than a +alpha particle (Gamma radiation has the greatest penetrating power).
- Nuclear Reactions:
- All Nuclear reactions are transmutations (examples: fission, fusion, decays)
- Unstable Elements:
- Any element after Po is naturally unstable and will spontaneously decay
- Stable Isotopes:
- Are not on table N (do not spontaneously emit particles)
- Decay Modes:
- Decay modes and half lives on table N (show alpha, beta, positron decay)
- Natural Transmutations:
- Show Spontaneous radioactive decay = 1 reactant ! 2 products (elements must change)
- Nuclear Decays:
- Release the decay particle
- Completing Nuclear Equations:
- Remember to add up mass number and atomic numbers on each side of the arrow (must be equal on both sides)
- Fusion:
- Light nuclei combine to form a heavy nucleus and a lot of energy (energy is sometimes in the form of a neutron)
- Fusion Energy:
- Fusion produces more energy than fission
- Energy Release:
- Nuclear reactions (such as fission or fusion) releases more energy than a chemical reaction (redox, substitution, neutralization)
- Mass Conversion:
- Nuclear reactions: mass is converted into energy
- Half Life:
- The length of time it takes for ½ mass of a sample to decay
- Half Life Sample:
- 1 half life = ½ sample remains, 2 half lives = ¼ sample remains, 3 half lives = 1/8 sample
- Half Life Question:
- Use table or timeline method
- Radioisotope Applications:
- Radioisotopes are used for dating of geological formations (C-14)
- I-131 used to diagnose thyroid disorders
- Radioisotopes can be used to detect diseases
- Radioisotopes can treat cancer but can also cause mutations in healthy cells (Co-60)
Unit 3: Matter
- Substance:
- Substance = compound or element
- Elements:
- Elements cannot be broken down by chemical means (it is an element if it is on the Periodic table/Table T)
- Compounds:
- Can be broken down by chemical means
- Same Compound:
- Same compound = same chemical property, different compound = different chemical properties
- Diatomics:
- 7 diatomics (two of the same atom bonded together) – BrINClHOF (Br2 ,I2 , N2 , Cl2 , H2 , O2 , F2)
- Table T:
- Melting Point (MP) and Boiling Point (BP) of elements on table T
- Liquid State:
- MP < Specific Temperature < BP
- Mixture:
- Can vary in proportion of its components (example: Salt water)
- Homogeneous Mixtures (Solutions):
- Even distribution of particles (aq-dissolved in water) substance has to be soluble to mix with water
- Heterogeneous Mixtures:
- Not even throughout. Contains a substance that will not be soluble in water.
- Substance Properties in Mixtures:
- When substances are mixed, they retain their properties
- Mixture Separation by Physical Means:
- Mixtures that contain substances with different density and particle size can be separated by physical means
- Separation Techniques:
- Mixture can be separated by chromatography, distillation and filtration
- Distillation:
- Separates liquids with different boiling points (water and alcohol)
- Chromatography:
- Method of separating particles by solubility and polarity
- Evaporation:
- Separates a salt dissolved in water
- Chemical Property:
- Is how substances react
- Chemical Change:
- Results in the formation of a difference substance (example: burning)
- Physical Change:
- Do not form new compounds, commonly phase changes (change in distance between molecules)
- States of Matter:
- Solids = atoms close together, liquid in the middle, gas = atoms far apart
- Solid Properties:
- Solids have a definite shape and definite volume
- Deposition:
- Gas to solid phase change
- Sublimation:
- Solid!Gas phase change (ex: CO2)
- Phase Change Diagram:
- In a phase change diagram, the flat parts represent the phase changes (Potential Energy [PE] changes and Kinetic Energy [KE] remains the same)
- In a phase change diagram, the sloped lines represent heating or cooling (PE remains the same and KE changes)
- Density:
- Density and Position:
- Higher density sinks to bottom of tank
- Element Density:
- Density never changes for each element (Found on Table S for elements)
Math and Significant Figures
- Significant Figures (Sig Figs):
- Atlantic/Pacific Rule:
- Decimal Absent: Count from the first nonzero number on the Atlantic side (right) and count all numbers to the left.
- Decimal Present: Count from the first nonzero number on the Pacific side (left) and count all numbers to the right.
- Atlantic/Pacific Rule:
- Multiplying/Dividing:
- Answer should be the lowest number of sig figs.
- Percent Error Formula:
- On table T.
Unit 4: Energy
- Kelvin Conversion:
- (0°C = 273 K)
- Kilojoules to Joules:
- 1 kJ = 1000 J
- Forms of Energy:
- Chemical, thermal, electromagnetic, electrical, nuclear, mechanical
- Thermal Energy:
- (heat) is measured in joules (J) = random motion of atoms and molecules
- Average Kinetic Energy:
- Average kinetic energy = temperature
- Thermal Energy and Mass:
- When two substances have the same temperature, the substance with the greater mass has more thermal energy
- Heat of Vaporization:
- Amount of heat required to vaporize a substance (table B for water constants) = 2260 J or J
- Heat of Fusion:
- Heat it takes to melt a substance is less than heat of vaporization because it requires less heat to melt a substance than boil a substance.
- Heat Flow:
- Heat flows from hot to cold
- Heat Equation:
- q is heat, m is mass, C is specific heat capacity [found on table B for water], ΔT is change in temperature. All info on table T
- Exothermic:
- Energy exits (is released).
- Endothermic:
- Energy absorbed (heat is shown on left side of equation) (examples of endothermic phase changes: s!l, l!g, s!g)
Unit 5: Gas Laws
- Pressure Effects:
- Pressure only effects gases
- Pressure Measurement:
- Pressure is measured in pascals
- STP Conditions:
- Standard Temperature and Pressure (STP) on table A (273 K and 1 atm or 101.3 kPa and 0C)
- Pressure and Temperature Relationship:
- Pressure and temperature have direct relationship (as pressure increases, temperature increases)
- Ideal Gas Conditions: PLIGHT
- Pressure Low, Ideal gas, High Temperature
- Ideal Gas Motion:
- Ideal gases move in random, constant, straight line motion
- Ideal Gas Separation:
- Ideal gases are separated by great distances compared to their size
- Ideal Gas Forces:
- Ideal gases have no attractive forces
- Gas Collisions:
- Collisions of gas may result in a transfer of energy
- Table H:
- Dotted line is the normal boiling of the substance
- Intermolecular Forces (IMF):
- Gases have the weaker IMF than solids
Unit 6: Periodic Table
- Mendeleev's Table:
- Organized by atomic mass.
- Modern Periodic Table:
- Elements arranged in order of atomic number.
- Periods and Groups:
- Periods are horizontal rows.
- Groups are vertical rows.
- Liquids on the Periodic Table:
- Bromine and Mercury.
- Metals:
- (left of staircase) are good conductors of heat, malleable.
- Metal Properties:
- Malleable because of the nature of the bonds between the atoms.
- Metal Electrons:
- Have fewer valence electrons than nonmetals.
- Metal Reactivity:
- Commonly react with nonmetals.
- Nonmetals:
- To the right of the staircase.
- Metalloids:
- Are on the staircase.
- Transition Metals:
- Form colored solutions in aqueous ion form.
- Halogens:
- (Group 17) – forms halide ions in solution.
- Noble Gases:
- (Group 18) are stable because of their stable electron configuration (8 valence electrons), they are not reactive
- Gaining/Losing Electrons:
- Elements will gain or lose electrons to be like noble gases
- Ions Formed by Metals:
- MELPS- Metals Electrons Lost form Positive Smaller ions
- Oxidation Numbers:
- Some groups will form the same oxidation numbers when gaining or losing electrons
- Group Properties:
- Same group/family = similar chemical properties because they have the same number of valence electrons
- Electronegativity:
- Attraction for electrons in a chemical bond = electronegativity (found on table T)
- Ionization Energy and Electronegativity Trends:
- First Ionization energy and electronegativity increases left to right (across a period) and decreases top to bottom (down a group)
- Atomic Radius Trends:
- Atomic radius (on table T) decreases left to right (across a period) and increases top to bottom (down a group)
- Atomic Radius and Energy Shells:
- Atomic radius increases down a group because more energy shells are added
Unit 7: Naming, Formulas, and Equations
- Ionic Formulas:
- Metal comes first, nonmetal second. Criss cross charges to get formula. Example: Calcium phosphate
- Naming Ionics with Table E:
- Say metal and then ion from table E. Ammonium examples shown
- Roman Numerals:
- Represent the charge of the metal
- Polyatomic Ions:
- Names on table E
- Balancing Equations:
- Number of each atom needs to be the same on both sides of the equation (use tallies). Use coefficients to balance
- Conservation:
- Mass, charge and energy are conserved in a chemical reaction
- Types of Chemical Reactions:
- Decomposition, single replacement, double replacement, synthesis
- Synthesis:
- Two or ore reactants combine to form one product
- Decomposition:
- One compound is broken down into two
- Single Replacement:
- One element switches partners
- Double Replacement:
- Think Do Si Do
Unit 8: Bonding
- BARF:
- Bond BROKEN energy ABSORBED (endothermic), energy RELEASED bond FORMED (exothermic)
- Compound Types:
- Ionic compound (metal and nonmetals or table E ions) and molecular compounds are all nonmetals with no table E ions
- Ionic Bonds and Table E:
- Ionic compounds with a table E ion have covalent and ionic bonds
- Ionic Compound Properties:
- Hard brittle solids with a high melting point, poor conductors as solids and good conductors in aq (higher concentration = better conductor)
- Metallic Bonding:
- Metals only!
- Ionic Bonds:
- Bond between metal and nonmetal or ion from table E
- Ionic Bond Electron Transfer:
- Transfer electrons from the valence shell of one atom to the valence shell of another atom
- Lewis Dot Diagrams:
- Have brackets for ionics. Molecular compounds: make sure all elements have eight electrons (except H) and the total number of electrons in diagram = total number of valence electrons
- Covalent Bond:
- Nonmetals (molecular compound)
- Nonpolar Covalent Bond:
- Bond between two of the same elements
- Multiple Covalent Bonds:
- Double (four electrons shared/ 2 pairs), triple (six electrons shared/ 3 pairs)
- Diatomic Molecules:
- Diatomic Oxygen molecule has double bond, diatomic nitrogen has triple
- Polarity of Bond:
- Electronegativity difference = polarity of bond (higher the difference, the more polar the bond)
- Molecule Polarity: SNAP
- Symmetrical Nonpolar, Asymmetrical Polar
- Intermolecular Forces (IMF):
- Stronger Intermolecular forces (IMF) = High boiling point
- Hydrogen Bonding:
- Example of IMF: hydrogen bonding (between H and F,O or N)
- Water Molecule Charges:
- (Oxygen is partially negative and hydrogen is partially positive)
- Charge Attraction:
- Positive and negative charges attract, like charges repel
Unit 9: Stoichiometry
- Atomic Mass:
- Atomic mass on the Periodic Table is in grams/ 1 mole
- GFM:
- (gram formula mass, formula mass or molar mass) is found by getting the mass of each element (multiplied by their subscript if they have one) and add all masses together
- Percent Composition by Mass:
- (Table T)
- Calculating Percent Composition:
- Can be calculated given a periodic table and chemical formula
- Mole Calculation:
- (Table T)
- Mole Ratio:
- Mole : mole ratio = coefficient : coefficient ratio
- Empirical Formula:
- Simplified formula, molecular is normal not simplified formula
- Conservation of Mass:
- Mass of products = mass of the reactants
Unit 10: Solutions
- Solubility Dependence:
- Solubility is dependent on temperature for solids (upward curve on table G)
- Table G:
- Use when given a temperature and asking about a salt dissolved in water (on the line is saturated, below = unsaturated, above = super)
- Solubility Rule:
- Likes dissolve likes (example: polar mixes with polar substances)
- Table F:
- (insoluble compounds will not fully dissolve in water and will be in solid phase, soluble compounds will dissolve in water and be in aq phase)
- Ion Effect:
- More ions more change in BP/FP
- Freezing Point Change:
- Add something to water (such as a salt) = freezing point decreases (more salt = lower the freezing point)
- Boiling Point Change:
- Add something to water (such as a salt) = BP increases (more salt = higher BP)
- Concentration Units:
- m/L or PPM
- Parts Per Million (PPM):
- [formula on table T]
- Molarity Calculation:
- formula on Table T
Unit 11: Kinetics
- Reaction Conditions:
- For a chemical reaction to occur you need sufficient energy and proper orientation for new bonds to form
- Effective Collisions:
- Chemical reactions need effective collisions
- Temperature Effect:
- Increase temperature, increases reaction rate (more collisions)
- Pressure Effect:
- Increase pressure: increases reaction rate (more collisions)
- Concentration Effect:
- Lower concentration slow reaction rate because of less collisions
- Surface Area Effect:
- Greater surface area = higher rate of reaction
- Potential Energy Diagrams:
- Show energy of reaction and when a catalyst is add the energy of the reactants and products do not change
- Activation Energy:
- Goes from the reactants to top of curve
- Reverse Activation Energy:
- Goes from the products to top of curve
- Exothermic Reaction Energy Diagram:
- Potential energy diagram starts high and ends low for an exothermic reaction
- Heat of Reaction:
- Heat of reaction = potential energy of products – potential energy of the reactants
- Heat of Reaction Location:
- Heat of reaction (ΔH) is in the middle of a potential energy diagram
- Table I:
- Show heat of reaction (energy absorbed + ΔH energy released – ΔH
- Catalyst Action:
- Speeds up a reaction by providing a different reaction pathway that lowers the activation energy
- Entropy (Disorder):
- Gases have the highest entropy, then liquid/aq and solids have the lowest
- Nature's Trend:
- Nature undergoes changes towards higher entropy and lower energy
Equilibrium
- Equilibrium Definition:
- Forward reaction ! Reverse reaction " Equilibrium "
- Equilibrium State:
- At equilibrium the concentration of reactants and products remain constant because reaction rates of the forward and reverse reaction are equal
- Reaction Rates:
- Rate of forward reaction = rate of reverse reaction
- Closed System:
- Need a closed system to maintain equilibrium
- Equilibrium Shift:
- Shift to right make more products, shift to left make more reactants
- Equilibrium Principles:
- UP and AWAY, DOWN and TOWARDS
- Pressure Shift:
- Decrease pressure shift to the side with most number of moles
- Temperature Shift:
- Increase temperature shift away from heat
- Catalyst Effect:
- Adding catalyst= no shift
- Solution Equilibrium:
- Rate of dissolving equals rate of crystallization
- Dynamic Phase Equilibrium:
- Two phase changes going on in a sealed flask
Unit 12: Acids and Bases
- Electrolytes:
- Acids, bases, salts
- Electrolyte Conductivity:
- Conduct in aqueous solutions not in solid phase
- Arrhenius Theory:
- Describes the behavior of acids and bases
- Arrhenius Definitions:
- Acids yield H+ ion and bases have an OH-
- Acids & Bases on Tables K & L:
- Know CH3COOH is an acid, all other CH compounds are not electrolytes
- Alternate Acid/Base Theory:
- BAAD: BASES ACCEPT H+ ACIDS DONATE H+
- Acidity and pH:
- Most acidic compounds = lowest pH
- pH and Hydronium Ions:
- Lower the pH (more acid) = more hydronium ions
- pH Scale Changes:
- Concentration of hydronium ions increases by a factor of 10 when the pH goes down by 1 pH unit
- Neutral Solutions:
- Moles of OH- and H+ are equal in a neutral solution
- Neutralization Reactions:
- Acid + base ! salt + water
- Metal and Acid Reactions:
- Any metals above H2 on table J will react spontaneously with an acid
- Titration Equation:
- remember M is called molarity or concentration
- Titration Purpose:
- Determines the concentration of unknown acids or bases
- Indicators:
- Range on the reference table (table M) is when the color is in-between two primary colors
Unit 13: Redox Reactions
- Oxidation Number:
- Single atom = 0, look on reference table or use algebra for atoms with multiple charges (can also use reverse criss cross if all else fails)
- Electron Transfer:
- Redox reactions electrons are transferred (charge changes)
- Oxidation and Reduction:
- Oxidation: electrons are lost (electrons on right), Reduction: electrons are gained (electron on left) LEO the lion says GER
- Half Reactions:
- Show charges and electrons lost
- Balanced Redox:
- Balanced redox reaction has same number of electrons lost and gained (atoms and charges balanced)
- Table J Reactivity:
- Lower on table J is less reactive
- Active Metals:
- More active metals are higher on table J
- Oxidation/Reduction on Table J:
- Higher on table J more likely to be oxidized for metal side, lower more easily reduced
- Spontaneous Reactions on Table J:
- If the oxidized element is higher on table j then the reaction will be spontaneous
- Electrochemical Cell:
- AN OX RED CAT (anode oxidation, reduction cathode)
- Electron Flow:
- Electrons flow from anode to cathode
- Anode Mass:
- Anode mass will decrease because solid metal is going into aqueous
- Voltaic Cell:
- Chemical energy is converted to electrical energy spontaneously
- Electron Movement:
- Electrons flow through a wire for voltaic cells
- Ion Movement:
- Ions move through the salt bridge for a voltaic cell
- Electrolytic Cell:
- Electrical energy to chemical energy
- Power Source:
- Battery (power source) is needed for an electrolytic cell to provide electrical energy (electrolysis or electroplating)
- Electroplating:
- Cathode in an electrolytic cell is what is electroplated (key or spoon)
Unit 14: Organic Chemistry
- Organic Compounds:
- Must contain at least one carbon and one hydrogen
- Hydrocarbons:
- Contain only carbon and hydrogen
- Saturated Hydrocarbons:
- Have all single bonds (2 electrons shared)
- Unsaturated Compounds:
- Have double or triple bonds between carbons
- Organic Formulas:
- Empirical, structural, molecular
- Structural Formula:
- Shows bonds
- Carbon Bonding:
- Carbon (atomic number 6) can form chains, rings and networks
- Table P:
- Tells number of carbons (remember carbon always makes 4 bonds!)
- Homologous Series:
- On table Q (alkanes, alkenes, alkynes)
- Naming Alkenes:
- (use table Q), start from side with double bond and count number of carbons, put number to represent location of double bond
- Carbon Counting:
- Count carbons from side closest to double bond or functional group
- Isomers:
- Have same number of C’s and H’s but are in a different structural arrangement (same molecular formula)
- Isomer Properties:
- Different structure = different physical/chemical properties
- Functional Groups:
- Table R
- Functional Group Properties:
- Different Functional groups have different chemical properties
- Alcohols:
- Drawing structure of alcohol includes putting an OH
- Halides:
- Contains group 17 elements
- Organic Acids:
- Structure has C with a double bonded O and OH
- Amines:
- Contain N
- Organic Reactions:
- Esterification, addition, saponification, polymerization, fermentation, etc.
- Addition Reaction:
- Binary compound (two atoms bonded together) gets added to double/triple bonded compound to reduce the number of bonds
- Saponification:
- Organic reaction used to make soap
- Polymerization:
- Adding same compound together to make a chain
- Fermentation:
- Sugar + enzyme ! ethanol (alcohol) + carbon dioxide
Test Taking Skills
- Use the Reference Tables!
- Read Paragraphs Completely:
- Information you need MIGHT be in there
- Answer Every Question.
- Best Guess Approach:
- If you don’t know the answer take the best guess you can make
- Referring to the Reference Table:
- Refer to the reference table for any question you may have trouble on
- Using the Test to Take the Test:
- The answer or a hint may be in another question
- First Choice:
- Your first choice is usually your best choice (unless you read the question incorrectly the first time around)
- Double Check Reference Table:
- Even if you think you know a chemical symbol, formula or charge….look it up an the reference table anyway (Table S and Periodic Table help a lot with this)
- Skipping Questions:
- Skip a question if you are having a hard time and go back to it later
- Time Management:
- You have plenty of time to take the regents (3 hours). Take a 5 minute break after you are done with the test and then look over your answers.
- Healthy Habits:
- Eat a healthy meal the night before and for breakfast as well.
- Get a good night’s sleep. A tired mind is not as sharp and clear as a well-rested one.
- Relax!
- You have seen all this stuff before…it is somewhere in your brain!