HONORS CHEMISTRY 2 FINAL EXAM

Time to Suffer!!!!!!

6- Properties of Covalent Compounds

* sharing of e-
* occurs between elements that are similar
* ex) between two nonmetals or metalloids
* never conductive as a solid or as a solution in water
* do not dissolve in water
* exception: sugar
* shorter bond = higher force of attraction, higher bond E
* longer bond = lower force of attraction, lower bond E

6- Properties of Ionic Compounds

* transferring of e-
* nonmetal takes e- from metal
* forms crystal lattice
* brittle
* high melting/boiling point
* very strong bond
* when solid:
* ions in fixed position
* nonconductive
* when dissolved in water:
* ions move freely
* conductive

6- Properties of Metallic Bonding

* forms crystal lattice
* nucleus of a metal
* delocalized e- (sea of e-)
* free to move about the entire crystal lattice
* orbitals overlap
* malleable and ductile
* high melting/boiling point and heat of evaporation
* strong bonds
* conductive as solid
* insoluble
* luster

6- Lewis Structures

* ionic compound- composed of cations (metals) and anions (nonmetals)
* Lewis Structures must be electrically neutral

6- Polarity

* nonpolar molecules:
* dipoles cancel
* ends have same partial charges
* polar molecules:
* dipoles do not cancel
* ends have opposite partial charges

6- Shapes of Molecules (molecular geometry)

* linear
* bent
* trigonal planar
* trigonal pyramidal
* Tetrahedral

6- Intermolecular Forces

* London dispersion forces (LDF)
* all molecules have LDF
* weakest IMF
* dipole-dipole force
* any polar molecule that doesn’t have H bonding has this
* hydrogen bonding
* must be polar
* must have hydrogen bonded to high energy anion (N, O, or F)
* strongest IMF

7- Naming and Writing Chemical Formulas

* monatomic ions
* element symbol + charge
* ex) Na^+
* ex) O^2-
* ex) Zn(II)

7- Mass, Percent Composition, and Molar Mass Conversions

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* percent composition
* part/whole
* ex) percent of water in a hydrate:

molar mass H2O/molar mass of entire formula
* formula mass = molar mass
* Avogadro’s number = 6.022\*10^23


* molecules to moles uses Avogadro’s number
* 6.022\*10^23 molecules/1 mol
* formula units to moles uses Avogadro's number
* 6.022\*10^23 formula units/1 mol

7- Empirical and Molecular Formulas

* empirical formula is the smallest whole number ratio of the subscripts in a compound
* molecular formula is the actual formula of the compound
* x(empirical formula) = molecular formula
* x = molecular formula molar mass/empirical formula molar mass
* to find empirical formula:
* take grams of all elements in compound and convert to moles (if given percentages, just pretend they are grams, it doesn’t matter)
* divide all by the smallest amount of moles
* if there is a _.5, multiply all by 2
* use these numbers as subscripts for the formula (1s are implied)

8- Evidence of a chemical change

* color change
* gas production
* change in state of matter (formation of a precipitate)
* energy production/consumption

8- Chemical Equations

* reactants on left, products on right
* balanced when the amount of each element is equal on both sides
* must contain states of matter symbols
* coefficients- the only things that change
* balance atoms that appear only once on each side of the equation first
* balance polyatomic ions as single units
* balance H and O last
* if an atom can be balanced with a coefficient of 1/2, use it, then multiply all coefficients by 2 at the end

8- Predicting Products

* synthesis
* to or more substances combine to make a compound
* 1 product
* A + X → AX
* decomposition
* a single compound undergoes a reaction that produces two or more simpler substances
* 1 reactant
* AX → A + X
* single displacement
* one element replaces a similar element in a compound
* USES ACTIVITY SERIES
* one element can only replace a similar element if that similar element is lower on the activity series (back of periodic table)
* metal replacement
* A + BX → AX +B
* halogen replacement
* Y +BX → X + BY
* double displacement
* ions of two compounds trade places in an aqueous solution to form new compounds
* AX + BY → BX + AY
* combustion
* a substance combines with oxygen, releasing a large amount of energy in the form of heat or light
* CxHy (g) + O2 (g) → CO2 (g) + H2O (g) +Energy
* only contains elements hydrogen, oxygen, and carbon
* remember to balance!!!!!!!!

9- Yields

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* actual yield- the amount of product, affected by human/equipment error attained from a reaction in real-life experiment


* theoretical yield- the supposed amount of product attained from a reaction, based purely on its mol ratio with a known quantity of another reactant or product
* percent yield- way to exemplify the accuracy of an actual yield by comparing it to the theoretical yield
* percent yield= (actual/theoretical)\*100

9- Limiting Reactants

* coefficients indicate mol ratio
* limiting reactant- the reactant whose difference in a have/need table has a negative sign
* know how to apply have/need table
* excess reactant- the reactant whose difference in a have/need table has a negative sign
* know how to apply have/need table

10\.5, 12, and 13- Solute-Solvent Combinations

* solutions
* homogenous mixture
* smallest particle size
* 0.01-1 nm
* cannot be separated through filtration
* particles aren’t large enough to settle out
* colloids
* appears to be one phase, but is actually heterogenous on the particle level
* intermediate particle size
* 1-1000 nm
* cannot be filtered or settled
* some separation occurs if left to settle long enough
* exhibits tyndall effect
* particles large enough to scatter light (foam, fog, gel, etc.)
* suspensions
* visibly heterogenous
* ex) oil and water mixture
* can be filtered
* settles unless consistently agitated
* largest particle size
* 1000 nm or greater

10\.5, 12, and 13- Rate of Dissolving

* rate of dissolving- how much solute dissolves in solvent over time
* factors that effect ROD:
* ^temp. = ^ROD
* ^kinetic energy (particle velocity) = more particle collisions
* ^surface area = ^ROD
* ^contact = more particle collisions
* agitation = ^ROD
* ^contact = more particle collisions
* solubility curve- graph to model rate of dissolving
* y-axis: amount of solute
* x-axis: time

10\.5, 12, and 13- Solubility

* the amount of a substance, in grams, required to form a saturated solution with a specific amount of solvent
* dependent on:
* nature of solute and solvent
* temp. of solvent
* solubility equilibrium- solute is recrystallizing at the same rate that the crystal is dissolving

10\.5, 12, and 13- Electrolytes/Nonelectrolytes

* electrolytes- when dissolved in water, the resulting solution conducts electricity
* ionic compounds
* acids
* bases
* nonelectrolytes- when dissolved in water, the resulting solution is nonconductive
* molecular compounds

10\.5, 12, and 13- Common Solute-Solvent Combinations

* gas-gas
* gas-liquid
* liquid-liquid
* liquid-solid
* solid-liquid
* solid-solid

10\.5, 12, and 13- Miscibility

* like dissolves like
* polar dissolves in polar
* nonpolar dissolves in nonpolar
* ONLY APPLICABLE WITH LIQUIDS

10\.5, 12, and 13- The Dissolving Process

* 1) dissociation
* neg. end of water molecule attracted to cation, pos. end of water molecule attracted to anion
* pulls apart molecule
* 2) hydration
* water molecules surround anions and cations, oxygen faces cations and hydrogen faces anions

10\.5, 12, and 13- Enthalpy of Solution

* enthalpy of solution- the net amount of E absorbed when a specific amount of a solute dissolves
* exothermic
* neg. value
* the E of separation of solute and solvent particles is less than the E produced
* endothermic
* pos. value
* the E of separation of solute and solvent particles is greater than the E produced

10\.5, 12, and 13- Solubility of Gases

* Temperature
* inversely proportional with solubility
* Pressure
* directly proportional with solubility (Henry’s Law)

10\.5, 12, and 13- Density of Ice

* 0.92 g/ml

10\.5, 12, and 13- Net Ionic Equation

* total ionic equation, barring the spectator ions (ions that are identical on both sides of the equation)

10\.5, 12, and 13- Molarity

* unit of concentration
* derived unit- mol/liter
* expressed as “M”

17 and 18- Collision Theory

* things that must be obtained in order for 2 reactants to make a product:
* 1) sufficient energy (different for every reaction)
* 2) correct orientation

17 and 18- Reaction Mechanisms

* elementary steps- steps that make up a reaction mechanism
* to add elementary steps together, intermediates must be eliminated
* intermediates- substances that are produced in an early step and consumed in a later step
* slowest step- rate determining step
* even if a reaction is reversible, the reactants are on the left and the products are on the right
* reversible reaction- a reaction that can be executed both ways, denoted by double-headed arrow
* catalyst- consumed in early step and produced in later step

17 and 18- Energy Profile Diagrams

* y-axis: energy (usually in KJ)
* x-axis: course of reaction/reaction progress
* Ea: reactant energy to activated complex
* activated complex- sufficient energy, peak of graph
* activated complex lowered by catalyst
* Ea’: product energy to activated complex
* delta E forward = E of products - E of reactants
* when neg., reaction is exothermic (product E is less than reactant E)
* when pos., reaction is endothermic (product E is greater than reactant E)
* delta E reverse = same value as delta E forward, opposite sign

17 and 18- Equilibrium

* chemical equilibrium- when the rate of the forward reaction is = to the rate of the reverse reaction
* conc. of products and reactants is unchanged
* it doesn’t matter if the amount of reactants and products are equal, only that the rate of exchange between them is equal
* equilibrium constant:
* ratio of products and reactants at a given temp. (since there is no conc. change at equilibrium)
* this ratio is referred to as an equilibrium expression
* does not include pure solids/liquids
* uses molarity
* denoted by K (no units, no sig figs)
* small K values = reactants favored
* large K values = products favored
* K = 1 means reactants and products are equal

17 and 18- LeChatlier’s Principle

* LeChatlier’s principle- if a system at equilibrium is subjected to stress, the equilibrium is shifted in the direction that tends to relieve its stress
* stress: increase conc.-
* increase reactant- forward, no effect on K
* increase product- reverse, no effect on K
* stress: decrease conc.-
* decrease reactant- reverse, no effect on K
* decrease product- forward, no effect on K
* stress: change in temp.
* increase temp.- reverse, K gets smaller
* decrease temp.- forward, K gets bigger
* stress: pressure-
* increase pressure- forward, no effect on K
* decrease pressure- reverse, no effect on K

14 and 15- Classifying Acids and Bases

* arrhenius acid
* produces a hydrogen ion: H+
* OR
* produces a hydronium ion: H3O+
* these are the same thing but proving your claim with a dissociation equation will result in a H+ proof and an ionization equation will result in a H3O+ proof


* arrhenius base
* produces a OH- ion
* if ionic: prove with dissociation equation
* if molecular: prove with ionization equation
* bronsted-lowry
* acid: proton donor
* base: proton acceptor
* proton = H+ or H3O+ ion
* acids and bases are reactants, never products
* acids always have “H” as first listed element in formula
* lewis
* acid: electron pair acceptor; no unshared pairs on central atom
* base: electron pair donor; unshared pairs on central atom
* conjugate acid- the product that has received the proton
* conjugate base- the product that has lost the proton

14 and 15- More Acid/Base Definitions

* amphoteric- acts as an acid or a base, dictated by the substance it is reacting with
* ex) H2O, also written as HOH (has both H+ and OH-)
* nonmetal oxides will react with water to form an acid- can be shown through a simple synthesis equation
* this is the process for acid rain
* MEMORIZE: 3NO2 (g) + H2O (l) → 2HNO3 (aq) + NO (g)
* only nonmetal oxide + water equation that won’t just synthesize

14 and 15- Titration

* titration- the controlled addition and measurement of the amount of a solution of known conc. required to completely react with a measured amount of unknown conc.
* equivalence point- moles acid = moles base
* “end” of titration
* reached when indicator turns color

14 and 15- Strong vs. Weak Acids and Bases

* strong acids:
* completely dissociate
* strong electrolyte (lots of ions in solution)
* identified by:
* list of strong acids on periodic table (MEMORIZE!!!)
* equation has single headed arrow (this is your proof)
* weak acids:
* slightly dissociate
* weak electrolyte (few ions in solution)
* identified by:
* any acid not on strong acid list
* equation has double headed arrow (this is your proof)
* strong bases:
* completely dissociate
* strong electrolyte (lots of ions in solution)
* identified by:
* contains group 1/2 metal and OH- (this is your proof)
* weak bases:
* slightly dissociate
* weak electrolyte (few ions in solution)
* identified by:
* contains metal not from group 1/2 and OH- (this is your proof)

14 and 15- Equivalence Point

* strong acid and strong base-
* equivalence point = pH 7
* weak acid and strong base-
* equivalence point > pH 7
* strong acid and weak base-
* equivalence point < pH 7

14 and 15- Toolbox Square

14 and 15- Titration Stoichiometry Sig Fig Rules

* # of sig figs in conc. (molarity) = # of decimal places in pOH or PH

14 and 15- Weak Acid Stoichiometry

* since weak acids do not completely dissociate, you can’t use a mole ratio
* you must use a RICE table
* remember: no pure liquids or solids in RICE tables!!!!!!

14 and 15- Endpoint

* the pH indicator is the color that indicates complete titration